Public | |
Traded as | NYSE: DLB (Class A) Russell 1000 Component |
---|---|
Industry | Audio encoding/compression Audio noise reduction |
Founded | May 18, 1965; 54 years ago in London, England, United Kingdom |
Founder | Ray Dolby |
Headquarters | , |
30+ (2014) | |
Area served | Worldwide |
Peter Gotcher (Executive chairman) Kevin Yeaman (President and CEO) | |
Products | Dolby ScreenTalk Dolby Media Producer Dolby Lake Processor |
Revenue | US$1.082 billion (2017)[1] |
US$248.64 million (2017)[1] | |
US$201.80 million (2017)[1] | |
Total assets | US$2.534 billion (2017)[1] |
Total equity | US$2.137 billion (2017)[1] |
Number of employees | 1,867 (2015)[2] |
Subsidiaries | Audistry[3] Via Licensing[4] |
Website | www.dolby.com |
Dolby Laboratories, Inc. (often shortened to Dolby Labs and known simply as Dolby) is an American company specializing in audio noise reduction and audio encoding/compression. Dolby licenses its technologies to consumer electronics manufacturers.
- 2Technologies
History[edit]
Dolby Labs was founded by American Ray Dolby (1933–2013) in London, United Kingdom, in 1965. In that same year, he invented the Dolby Noise Reduction System, a form of audio signal processing for reducing the background hissing sound on audio tape recordings. His first U.S. patent on the technology was filed in 1969, four years later. The method was first used by Decca Records in the UK.[5]
He moved the company headquarters to the United States (San Francisco, California) in 1976.[6] The first product Dolby Labs produced was the Dolby 301 unit which incorporated Type A Dolby Noise Reduction, a compander based noise reduction system. These units were intended for use in professional recording studios.
Dolby was persuaded by Henry Kloss of KLH to manufacture a consumer version of his noise reduction. Dolby worked more on companding systems and introduced Type B in 1968.
Dolby also sought to improve film sound. As the corporation's history explains:[citation needed]
- Upon investigation, Dolby found that many of the limitations in optical sound stemmed directly from its significantly high background noise. To filter this noise, the high-frequency response of theatre playback systems was deliberately curtailed… To make matters worse, to increase dialogue intelligibility over such systems, sound mixers were recording soundtracks with so much high-frequency pre-emphasis that high distortion resulted.
The first film with Dolby sound was A Clockwork Orange (1971), which used Dolby noise reduction on all pre-mixes and masters, but a conventional optical sound track on release prints. Callan (1974) was the first film with a Dolby-encoded optical soundtrack.[7] In 1975, Dolby released Dolby Stereo, which included a noise reduction system in addition to more audio channels (Dolby Stereo could actually contain additional center and surround channels matrixed from the left and right). The first film with a Dolby-encoded stereo optical soundtrack was Lisztomania (1975), although this only used an LCR (Left-Center-Right) encoding technique. The first true LCRS (Left-Center-Right-Surround) soundtrack was encoded on the movie A Star Is Born in 1976. In less than ten years, 6,000 cinemas worldwide were equipped to use Dolby Stereo sound. Dolby reworked the system slightly for home use and introduced Dolby Surround, which only extracted a surround channel, and the more impressive Dolby Pro Logic, which was the domestic equivalent of the theatrical Dolby Stereo.[8]
Dolby developed a digital surround soundcompression scheme for the cinema. Dolby Stereo Digital (now simply called Dolby Digital) was first featured on the 1992 film Batman Returns. Introduced to the home theater market as Dolby AC-3 with the 1995 laserdisc release of Clear and Present Danger, the format did not become widespread in the consumer market, partly because of extra hardware that was necessary to make use of it, until it was adopted as part of the DVD specification. Dolby Digital is now found in the HDTV (ATSC) standard of the United States, DVD players, and many satellite-TV and cable-TV receivers.Dolby developed a digital surround soundcompression scheme for TV series The Simpsons.[citation needed]
On February 17, 2005, the company became public, offering its shares on the New York Stock Exchange, under the symbol DLB. On March 15, 2005, Dolby celebrated its fortieth anniversary at the ShoWest 2005 Festival in San Francisco.[citation needed]
On January 8, 2007, Dolby announced the arrival of Dolby Volume at the International Consumer Electronics Show. It enables users to maintain a steady volume while switching through channels or program elements (i.e., loud TV commercials).[citation needed]
On June 18, 2010, Dolby introduced Dolby Surround 7.1, and set up theaters worldwide with 7.1 surround speaker setups to deliver theatrical 7.1 surround sound. The first film to be released with this format was Pixar's Toy Story 3 which was later followed by 50 releases using the format. As of April 2012, there are 3,600 Dolby Surround 7.1 movie theaters.
In April 2012, Dolby introduced its Dolby Atmos, a new cinematic technology adding overhead sound, first applied in Pixar's motion picture Brave.[9] In July 2014, Dolby Laboratories announced plans to bring Atmos to home theater. The first television show to use the technology on disc was Game of Thrones.
On February 24, 2014, Dolby acquired Doremi Labs for $92.5 million in cash plus an additional $20 million in contingent consideration that may be earned over a four-year period.[10]
In May 2019, Dolby decided to add Dolby Atmos to hundreds of newer songs in the music industry.
Technologies[edit]
Analog audio noise reduction[edit]
- Dolby A: professional noise reduction systems for tapes and analog cassettes.
- Dolby NR/B/C/S: consumer noise reduction systems for tapes and analog cassettes.
- Dolby SR (Spectral Recording): professional four-channel noise reduction system in use since 1986, which improves the dynamic range of analog recordings and transmissions by as much as 25 dB. Dolby SR is utilized by recording and post-production engineers, broadcasters, and other audio professionals. It is also the benchmark in analog film sound, being included today on nearly all 35 mm film prints. On films with digital soundtracks, the SR track is used in cinemas not equipped for digital playback, and it serves as a backup in case of problems with the digital track.
- Dolby FM: noise reduction system for FM broadcast radio. Dolby FM was tried by a few radio stations starting with WFMT in 1971. It used Dolby B, combined with 25 microsecond pre-emphasis. A small number of models of tuners and receivers were offered with the necessary decoder built in. In addition, a few cassette deck models appeared that allowed the deck's internal Dolby B decoder to be put in the line in to line out 'pass-through' path, permitting its use with Dolby FM broadcasts. The system was not successful and was on the decline by 1974.
- Dolby HX Pro: single-ended system used on high-end tape recorders to increase headroom. The recording bias is lowered as the high frequency component of the signal being recorded increases, and vice versa. It does nothing to the actual audio that is being recorded, and it does not require a special decoder. Any HX Pro recorded tape will have, in theory, better sound on any deck.
- Dolby Advanced Audio: Dolby surround sound, locking preferred volume level, optimizes audio performance for specific PC model and lets turning up the volume to the built-in speakers without distorting the sound.[11]
Audio encoding/compression[edit]
- Dolby Digital (also known as AC-3) is a lossy audio compression format. It supports channel configurations from mono up to six discrete channels (referred to as '5.1'). This format first allowed and popularized surround sound. It was first developed for movie theater sound and spread to Laserdisc and DVD. It has been adopted in many broadcast formats including all North American digital television (ATSC), DVB-T, direct broadcast satellite, cable television, DTMB, IPTV, and surround sound radio services. It is also part of both the Blu-ray and the now defunct HD DVD standards. Dolby Digital is used to enable surround sound output by most video game consoles. Several personal computers support converting all audio to Dolby Digital for output.
- Dolby Digital EX: introduces a matrix-encoded center rear surround channel to Dolby Digital for 6.1 channel output.[12] This center rear channel is often split to two rear back speakers for 7.1 channel output.
- Dolby Digital Plus (also known as E-AC-3) is a lossy audio codec based on Dolby Digital that is backward compatible, but more advanced. The DVD Forum has selected Dolby Digital Plus as a standard audio format for HD DVD video. It supports datarates up to 6 Mbit/s, an increase from Dolby Digital's 640 kbit/s maximum. On Blu-ray, Dolby Digital Plus is implemented differently, as a legacy 640 kbit/s Dolby Digital stream plus an additional stream to expand the surround sound, with a total bandwidth of approximately 1.7 Mbit/s. Dolby Digital Plus is also optimized for limited datarate environments such as Digital broadcasting.
- Dolby Digital Live is a real-time hardware encoding technology for interactive media such as video games. It converts any audio signals on a PC or game console into the 5.1-channel Dolby Digital format and transports it via a single S/PDIF cable.[13] A similar technology known as DTS Connect is available from competitor DTS.
- Dolby E selected hardware.Dolby E: professional coding system optimized for the distribution of surround and multichannel audio through digital two-channel post-production and broadcasting infrastructures, or for recording surround audio on two audio tracks of conventional digital video tapes, video servers, communication links, switchers, and routers. The Dolby E signal does not reach viewers at home. It is transcoded to Dolby Digital at lower datarate for final DTV transmission.
- Dolby Stereo (also known as Stereo A): original analog optical technology developed for 35 mm prints and is encoded with four sound channels: Left/Center/Right (which are located behind the screen) and Surround (which is heard over speakers on the sides and rear of the theatre) for ambient sound and special effects. This technology also employs A-type or SR-type noise reduction, listed above with regards to analog cassette tapes. See also Dolby Surround
- Dolby TrueHD: Offers bit-for-bit sound reproduction identical to the studio master. Over seven full-range 24-bit/96 kHz discrete channels are supported (plus a LFE channel, making it 7.1 surround) along with the HDMI interface. Theoretically, Dolby TrueHD can support more channels, but this number has been limited to 8 for HD DVD and Blu-ray Disc.
- Dolby Pulse: released in 2009, it is identical to the HE-AAC v2 codec except for the addition of Dolby metadata, which is common to Dolby's other digital audio codecs. This metadata 'ensures consistency of broadcast quality.'[14]
- Dolby AC-4 is a lossy audio compression format which can contain audio channels and/or audio objects.
- Dolby Atmos: Star Wars Battlefront (2015 video game) was the first game encoded in Dolby Atmos. Has encoding support for up to 12 channels for theatres, and encodes up to a maximum of 8 channels for games and 4K movies. Each channel is encoded at 24-bit/128KHz and only supports for HDMI, DisplayPort. Digital optical is also supported with limitations, as you'll only get a full 5.1 channels, instead of the full 8.1 channels with HDMI, or DisplayPort.
Audio processing[edit]
Dolby system A-type decoder
- Dolby Headphone: an implementation of virtual surround, simulating 5.1 surround sound in a standard pair of stereo headphones.[15]
- Dolby Virtual Speaker: simulates 5.1 surround sound in a setup of two standard stereo speakers.[15]
- Dolby Surround, Dolby Pro Logic, Dolby Pro Logic II, Dolby Pro Logic IIx, and Dolby Pro Logic IIz: these decoders expand sound to a greater number of channels. All can decode surround sound that has been matrixed into two channels; some can expand surround sound to a greater number of speakers than the original source material. See the referenced articles for more details on each decoder.
- Audistry: sound enhancement technologies[16]
- Dolby Volume: reduces volume level changes[17]
- Dolby Mobile: A version of Dolby's surround sound technology specifically designed for mobile phones, notably the HTC Desire HD, LG Arena and LG Renoir
- Dolby Audio Plug-in for Android: An API packaged as a Java Library that allows Android Developers to take advantage of Dolby Digital Plus Technology embedded into mobile and tablet devices, notably the Fire HD, Fire HDX, and Samsung Galaxy Tab 3 series.
Video processing[edit]
- Dolby Contrast provides enhanced image contrast to LCD screens with LED backlight units by means of local dimming.[18]
- Perceptual Quantizer (PQ), published by SMPTE as SMPTE ST 2084, is a transfer function that allows for the display of high dynamic range (HDR) video with a luminance level of up to 10,000 cd/m2 and can be used with the Rec. 2020 color space.[19][20][21][22] On August 27, 2015, the Consumer Electronics Association announced the HDR10 Media Profile which uses the Rec. 2020 color space, SMPTE ST 2084, and a bit depth of 10-bits.[23] On August 2, 2016, Microsoft released the Windows 10 Anniversary Update, which supports the HDR10 format with PQ (ST 2084) transfer function and Rec.2020 color space.[24]
- Dolby Vision is content mastering and delivery format similar to HDR10 media profile. It supports both high dynamic range (HDR) and wide color gamut (ITU-R Rec. 2020 and 2100) at all stages from content creation and production to transmission and playback. Dolby Vision includes the Perceptual Quantizier (SMPTE ST-2084) electro-optical transfer function and supports displays with up to 10,000-nit maximum brightness (4,000-nit in practice). It also provides up to 4K resolution and color depth of up to 12-bits (backward compatible with current 8-bit and 10-bit displays).[25] Dolby Vision can encode mastering display colorimetry information using static metadata (SMPTE ST 2086) and dynamic metadata (SMPTE ST 2094-10, Dolby format) for each scene.[26] Examples of Ultra HD (UHD) Dolby Vision is available in TV, monitor, mobile device and theater. Dolby Vision content can be delivered on Ultra HD Blu-ray discs,[27][28] over conventional broadcasting, OTT, and online streaming media services.[29] Dolby Vision metadata can be carried via HDMI interface versions 1.4b and above.[30]
- ICtCp provides an improved color representation that is designed for high dynamic range (HDR) and wide color gamut (WCG).[31] An improved constant luminance is an advantage for color processing operations such as chroma subsampling and gamut mapping where only color information is changed.[31] ICtCp is based on a modification of IPT called ICaCb.[32]
Digital cinema[edit]
- Dolby Digital Cinema[33]
- Dolby 3D[34]
- Dolby Atmos[35]
- Dolby Cinema, a premium cinema concept developed by Dolby Laboratories as a direct competitor to IMAX[36]
Live sound[edit]
- Dolby Lake Processor[37] - as of 2009, all Lake products are owned by Lab Gruppen[38]
Dolby Surround systems at a glance[edit]
Over the years Dolby has introduced several surround sound systems. Their differences are explained below.
Decoder | Encoder | Year | Description | Channels |
---|---|---|---|---|
Dolby Stereo | 1975 | Cinema use with optical technology. Uses Dolby A for noise reduction. Upmix stereo to Surround 4.0 | FL FR with C and MonoSurround matrixed | |
Dolby Surround | Dolby Surround | 1982 | First Home use. Analog. Upmix stereo to Surround 3.0 | FL FR and MonoSurround matrixed |
Dolby Stereo SR | 1986 | Cinema use. Uses Dolby SR for noise reduction. | FL FR with C and MonoSurround matrixed | |
Dolby Pro Logic | 1986-1987 | Improved Dolby Surround. Upmix Stereo to Surround 4.0. | FL FR with C and MonoSurround matrixed | |
Dolby Digital | Dolby Stereo AC3 | 1986 Modern 1992 Film 1995 Laser Disc | Discrete channel encoder/decoder. Pro Logic Decoder can be used for downmixed stereo inputs. | FL FR C SL SR SUB |
Dolby Digital EX/Dolby Digital Surround EX | 1999 | non-discrete 6.1 or 7.1 (5.1 with Center Rear matrixed onto SL & SR) | FL FR C SL SR (with matrixed RearMono) SUB [non-discrete 7.1: BackLeft and BackRight] | |
Dolby Pro Logic II | 2000 | Improved Dolby Pro Logic. Upmix Stereo to Surround 5.1 in either Movie, Music, or Game mode. | FL FR C SL SR SUB | |
Dolby Pro Logic IIx | 2002 | Upmix Stereo or Surround 5.1 to 6.1 or 7.1 in either Movie, Music, or Game mode. | FL FR C SL SR SUB Left Back and Right Back | |
Dolby Digital Plus | Dolby Media Encoder | 2005 | Lossy compression codec; 48 kHz sampling frequency, 20-bit word length; supports data rates of 32 kbit/s – 6 Mbit/s, scalable, including 768 kbit/s – 1.5 Mbit/s on high-definition optical discs, typically, and 256 kbit/s for broadcast and online. 1.0- to 7.1-channel support for current media applications; extensible to 16 channels; discrete. Backward compatible with Dolby Digital through S/PDIF connection up to 640 kbit/s. Supports Dolby Metadata. | FL FR C SL SR SUB Left Back and Right Back |
Dolby TrueHD | Dolby Media Encoder | 2005 | Lossless compression codec; supports 44.1 kHz to 192 kHz sampling frequency up to 24-bit word length; supports variable data rate up to 18 Mbit/s; maximum channel support is 16 channels as presently deployed. Higher bitrate than Dolby Digital Plus. Blu-ray Disc channel support up to eight channels of 96 kHz/24-bit audio; six channels (5.1) up to 192 kHz/24-bit; and two- to six-channel support up to 192 kHz/24-bit maximum bit rate up to the maximum of 18 Mbit/s. | |
Dolby Pro Logic IIz | Dolby Laboratories | 2009 | Upmix Stereo or Surround 5.1/7.1 to 7.1 Height or 9.1 with the addition of front height channels. (Based on Dolby Pro Logic IIx.) | L, C, R, Ls, Rs, Lrs (Left Back), Rrs (Right Back), LFE, Lvh and Rvh |
See also[edit]
- CX (analog noise reduction competitor)
- dbx (analog noise reduction competitor)
- High Com (analog noise reduction competitor)
- DTS (digital soundspace competitor)
- Meridian Lossless Packing (lossless coding for DVD-Audio)
- SRS Labs (surround sound competitor)
- Sony Dynamic Digital Sound (digital soundspace competitor)
References[edit]
- ^ abcde'DLB Company Financials'. NASDAQ.
- ^'FAQ - Dolby Laboratories, Inc'. Dolby Laboratories. Archived from the original on February 17, 2015. Retrieved January 8, 2015.
- ^'Dolby Laboratories - Sound Technology, Imaging Technology, Voice Technology'. Audistry.com. Retrieved 2012-04-26.
- ^'ViaLicensing'. ViaLicensing. Retrieved 2012-04-26.
- ^Williamson, Marcus (13 September 2013). 'Ray Dolby obituary: Inventor whose noise-reduction technology transformed sound reproduction'. The Independent.
- ^'50 Years of Innovation – Dolby History'. Dolby Laboratories. Retrieved September 14, 2017.
- ^Sergi, Gianluca (2004). The Dolby Era: Film Sound in Contemporary Hollywood. Manchester University Press. p. 46. ISBN0719070678.
- ^'Star Wars and the Explosion of Dolby Stereo - Tested.com'. Tested.
- ^'Pixar's Brave to debut new Dolby Atmos sound system'. BBC News. BBC. 25 April 2012. Retrieved 2012-04-26.
- ^'Dolby Signs Agreement to Acquire Doremi Labs'. Dolby.com. 2014-02-24. Retrieved 2014-02-24.
- ^'Dolby Advanced Audio v2'. www.dolby.com.
- ^'Dolby Digital EX'. Dolby.com. Retrieved 2012-04-26.
- ^'Dolby Digital Live'. Dolby.com. Retrieved 2012-04-26.
- ^'Dolby Pulse - combining the merits of Dolby Digital and HE-AAC'(PDF). Retrieved 2008-12-10.
- ^ ab'Dolby Headphone with 5.1 Surround Sound Stereo'. Dolby.com. Retrieved 2012-04-26.
- ^'Dolby Laboratories - Sound Technology, Imaging Technology, Voice Technology'(PDF). Audistry.com. Retrieved 2012-04-26.
- ^'Dolby Volume'. Dolby.com. Retrieved 2012-04-26.
- ^'Dolby Debuts New Video Technologies at International CES 2008'. Dolby press release. Archived from the original on 2008-04-17. Retrieved 2008-03-28.
- ^Adam Wilt (2014-02-20). 'HPA Tech Retreat 2014 – Day 4'. DV Info Net. Retrieved 2014-11-05.
- ^'ST 2084:2014'. Society of Motion Picture and Television Engineers. Retrieved 2015-09-21.
- ^Chris Tribbey (2015-07-10). 'HDR Special Report: SMPTE Standards Director: No HDR Format War, Yet'. MESA. Archived from the original on 2015-09-13. Retrieved 2015-09-21.
- ^Bryant Frazer (2015-06-09). 'Colorist Stephen Nakamura on Grading Tomorrowland in HDR'. studiodaily. Retrieved 2015-09-21.
- ^Rachel Cericola (2015-08-27). 'What Makes a TV HDR-Compatible? The CEA Sets Guidelines'. Big Picture Big Sound. Retrieved 2015-09-21.
- ^'High Dynamic Range and Wide Color Gamut (Windows)'. msdn.microsoft.com.
- ^Dolby Laboratories. 'Dolby Vision'(PDF). Retrieved 2016-08-24.
- ^'SMPTE ST 2094 and Dynamic Metadata'(PDF). Society of Motion Picture and Television Engineers. Retrieved 2017-01-25.
- ^Caleb Denison (2016-01-28). 'Ultra HD Blu-ray arrives March 2016; here's everything we know'. Digital Trends. Retrieved 2016-07-27.
- ^Michael S. Palmer (2016-02-10). 'Hands On First Look: Samsung UBD-K8500 Ultra HD Blu-ray Player'. High-Def Digest. Retrieved 2016-07-27.
- ^'Dolby Vision'. Dolby.com. Retrieved 2012-04-26.
- ^'Dolby Vision FAQ'. yoeri.geutskens.com.
- ^ ab'ICtCp Dolby White Paper'(PDF). Dolby. Retrieved 2016-04-20.
- ^Jan Froehlich; Timo Kunkel; Robin Atkins; Jaclyn Pytlarz; Scott Daly; Andreas Schilling; Bernd Eberhardt (2015-10-18). 'Encoding Color Difference Signals for High Dynamic Range and Wide Gamut Imagery'(PDF). Society for Imaging Sciences and Technology. Retrieved 2016-08-26.
- ^'Dolby Digital Cinema'. Dolby.com. Retrieved 2012-04-26.
- ^Dolby 3D Movie TechnologyArchived July 8, 2009, at the Wayback Machine. Dolby.com. Retrieved on 2013-12-09.
- ^Content Creators, Distributors, Exhibitors: Introducing Dolby Atmos™. Dolby.com. Retrieved on 2013-12-09.
- ^Dolby Cinema the Total Cinema Experience. Dolby.com Retrieved on 2014-12-17.
- ^'Dolby Lake Processor'(PDF). Retrieved 2012-04-26.
- ^'About Lake'.
External links[edit]
- Dolby Laboratories companies grouped at OpenCorporates
Retrieved from 'https://en.wikipedia.org/w/index.php?title=Dolby_Laboratories&oldid=899050861'
Windows 10’s Creators Update added support for Dolby Atmos positional sound. This includes two things: Support for Dolby Atmos hardware and virtual Dolby Atmos sound that works in any pair of headphones.
The Dolby Atmos for headphones feature is a bit weird. It appears in the standard Windows control panel as an option, but it requires a free trial or $14.99 purchase via the Windows Store before you can actually use it.
What Is Dolby Atmos?
Traditional 5.1 or 7.1 surround sound uses 5 or 7 speaker channels, plus a subwoofer. When you watch a movie or play a game with surround sound, that movie or game is actually sending 6 or 8 separate channels of sound to your speakers.
Dolby Atmos is an improved type of surround sound. It isn’t mixed into several separate channels; instead, sounds are mapped to virtual locations in 3D space, and that spatial data is sent to your speaker system. A Dolby Atmos-enabled receiver then uses specially calibrated speakers to position these sounds. Dolby Atmos systems may include ceiling-mounted speakers above you or speakers on the floor that bounce their sound off the ceiling, for example.
This feature requires Dolby Atmos-enabled hardware, notably a Dolby Atmos-enabled receiver. Microsoft also just added Dolby Atmos support to the Xbox One, and many Blu-ray discs include Dolby Atmos audio.
RELATED:What’s the Difference Between Virtual and “True” Surround Sound Gaming Headsets?
Windows 10’s Creators Update also added a separate feature named “Dolby Atmos for headphones”. This feature promises improved positional audio in any pair of headphones or earbuds. You don’t need special Dolby Atmos headphones. It’s a type of virtual surround sound built into Windows.
Really, this is a completely different feature that’s only linked by Dolby’s branding. True Dolby Atmos requires a hardware receiver and special speaker setup, while Dolby Atmos for headphones is a digital signal processor (DSP) that takes surround sound from your PC and mixes it to offer an improved positional sound experience in headphones.
Some games have already added support for Dolby Atmos for headphones. For example, Blizzard’s Overwatch includes built-in Dolby Atmos support, and it works even if you’re not running Windows 10’s Creators Update. You can enable this feature from Options > Sound > Dolby Atmos for Headphones in Overwatch. Blizzard argues that Atmos offers an improved experience that allows you to more easily pinpoint where sounds are coming from in the game.
How to Enable Dolby Atmos on Windows 10
To start using this feature, download the Dolby Access app from the Windows Store and launch it.
The app will guide you through setting this up. If you have Dolby Atmos receiver you want to use with your PC, select “With my home theater”. If you want to use any pair of headphones, select “With my headphones”.
If you select a home theater PC, you’ll be given a link to enable the “Dolby Atmos for home theater” option in the Windows Sound settings control panel. After you do, the app will prompt you to calibrate your system. There’s no additional purchase necessary for the home theater option—you just need the hardware.
If you select headphones, you’ll be prompted to confirm your PC’s sound hardware supports the Windows 10 spatial audio platform for headphones. Modern PCs should have sound drivers that support this feature, but you may be out of luck if you have a much older PC you’ve upgraded to Windows 10.
The Dolby Atmos for headphones feature isn’t free. While Microsoft integrated it into Windows, Microsoft clearly didn’t pay the licensing fees to allow any Windows user to use it.
You can still try Dolby Atmos for headphones for free, however. Click the “30-day trial” button to enable it.
Once you’ve enabled the free trial, you’ll be prompted to enable Dolby Atmos for headphones. Click the “Configure PC settings” button and then select “Dolby Atmos for headphones” in the Spatial sound format box.
This option actually appears in the properties window for your audio device even if you don’t have the Dolby app installed. However, if you try to enable this feature without installing the app first, Windows will prompt you to install the Dolby Access app from the Windows Store first.
How to Test Dolby Atmos
The Dolby Access app will allow you to test Dolby Atmos by playing a variety of videos that support Dolby Atmos audio.
While the videos are impressive enough, you’ll want to actually test Dolby Atmos by playing some PC games or watching some surround sound-enabled videos before paying for it and see if you can notice an appreciable difference. Some people say they notice an improvement, while others don’t notice much of a difference. It likely depends on the games you’re playing videos you’re watching, too.
When testing Dolby Atmos, be sure to enable 5.1 or 7.1 surround sound in whatever game or application you use. The application will then produce surround sound, and Dolby Atmos will mix it to stereo sound for your headset.
You’re free to test Dolby Atmos for 30 days, after which it will cost $14.99 to buy Dolby Atmos for headphones support from the Windows Store.
How to Try Microsoft’s Free Alternative, Windows Sonic for Headphones
Windows 10’s Creators Update also offers a free “Windows Sonic for Headphones” option you can enable instead of Dolby Atmos. Just right-click the speaker icon in your system tray, select “Playback Devices”, click your playback device, and click “Properties”. On the Spatial sound tab, select “Windows Sonic for Headphones”.
You may want to test this feature to see how it compares to Dolby Atmos for Headphones in your games and videos. We’ve seen some people say it doesn’t work quite as well as the Dolby Atmos option in their experience, but we’ve also seen some people say they don’t notice much of a difference.
When it comes to sound, everyone often has their own opinion. Audio quality can be very subjective.
Surround sound is an integral part of the home theater experience, and with that, there are lots of surround sound formats in use, depending on your audio system's capabilities, speaker layout, and content.
Probably the most used are formats that are part of the Dolby Digital family. In this article, we discuss three: Dolby Digital, Dolby Digital EX, and Dolby Digital Plus. These formats are commonly used on DVDs and streaming content and are also present as a supplemental selection in Blu-ray and Ultra HD Disc content.
What Dolby Digital Is
Dolby Digital is a digital audio encoding system designed for use on DVDs, Blu-ray, and Ultra HD Blu-ray Discs, and, in some cases, for TV broadcast and streaming content. This system provides efficient transfer for audio signals that may be composed of one, or more channels, that can be decoded by a home theater receiver or AV Preamp/Processor with a Dolby Digital decoder and distributed to one or more speakers.
Almost all home theater receivers in use have a built-in Dolby Digital decoder and all DVD, Blu-ray Disc, and Ultra HD Blu-ray Disc players are equipped with the ability to pass Dolby Digital signals via a technique referred to as bitstream to properly equipped receivers for decoding.
Dolby Digital is often referred to as a 5.1 channel surround system. However, the term 'Dolby Digital' refers to the digital encoding of the audio signal, not how many channels it has. Dolby Digital may also be referred to asDD, DD 5.1, AC3
- Monophonic: Represented by one or two speakers. However, with two speakers, both reproduce the same sound so the sound will appear to come from the space between the speakers.
- 2-Channels: Represented by two speakers - one on the left and on the right front of the listening position.
- 4-Channels: Represented by four speakers - Two placed on the left and right front of the listening position, and two on the left and right, and slightly behind the listening position.
- 5.1 Channels: Represented by five speakers (left, center, right, left surround, right surround), and a subwoofer (.1)
Dolby Digital EX
The Dolby Digital EX format adds a third surround channel that is placed directly behind the listener. The means that it is a 6.1 Channel system.
The six channels are represented by six speakers (left, center, right, left surround, center back, right surround), and a subwoofer (.1.).
This means that the listener has both a front center channel and, with Dolby Digital EX, a rear center channel. If you are losing count, the channels are labeled: left front, center front, right front, left surround, right surround, subwoofer, with a surround back center. A home theater receiver with a Dolby Digital EX decoder is required to access the full 6.1 channel experience.
However, if you have a DVD, or other source content, that contains 6.1 channel EX encoding and your receiver does not have an EX decoder, the receiver will default to Dolby Digital 5.1. What it does is sort out the extra EX information and distribute/mix it within a 5.1 channel sound field.
Usually, this means that the 6th (center back) channel is placed into both the left and right surround channels as a mono signal, which in turn creates a 'phantom' rear center back channel without having to have a physical rear center speaker.
This is not as accurate as a setup that includes a dedicated rear center channel speaker as the output level can't be adjusted independently of the left and right surround channels, but you are still able to hear the sound that was originally encoded for the center back channel.
Dolby Digital Plus
Dolby Digital Plus is a high definition digital-based surround sound format that supports up to 8-channels (7.1) of surround decoding. The channel distribution is as follows: front left, front center, front right, left surround, right surround, left surround back, right surround back, and subwoofer.
In addition, Dolby Digital Plus contains a standard Dolby Digital 5.1 bitstream that is compatible with standard Dolby Digital-equipped receivers. This means on a 5.1 channel receiver you will hear a 5.1 channel mix of the soundtrack, rather than a 7.1 channel mix. The surround back left and right channels are folded into the left and right surround channels.
Dolby Digital Plus is one of the several audio formats employed by Blu-ray Disc format. Dolby Digital Plus is compatible with the audio portion of the HDMI interface, as well as being applied in streaming and mobile audio applications. Dolby Digital Plus is also built into the Dolby Audio platform for Windows 10 and the Microsoft Edge browser.
Although Dolby Digital Plus has its own specific label designation, in many applications, Dolby Digital 5.1 and 6.1 (EX) are often referred to as just Dolby Digital.
No matter which format in the Dolby Digital family discussed above you have access to, the goal is to provide a room-filling surround sound listening experience that enhances the home theater viewing experience or a fuller audio experience from a compatible home theater receiver, PC, or portable device.
However, depending on your content and components, there are additional Dolby home theater audio formats to be aware of including Dolby TrueHD and Dolby Atmos.
Dolby Digital is the next step forward in sonic realism and listener involvement. It has already changed the way you experience your favorite films in movie theaters, and is now doing the same for video programming at home.
1. What is Dolby Digital?
Dolby Digital is an advanced form of digital audio coding that makes it possible to store and transmit high-quality digital sound far more efficiently than was previously possible. First used in movie theaters in 1992, it is the result of decades spent by Dolby Laboratories developing signal-processing systems that exploit the characteristics of human hearing.
2. What program sources deliver Dolby Digital audio?
Dolby Digital audio is available via laser discs, DVD-Video discs, DVD-ROM discs for computers, digital cable systems, direct broadcast satellite (DBS) systems, and digital broadcast TV (DTV). They are usually identified with the Dolby Digital logo.
3. Can I hear Dolby Digital programs over a regular stereo or Dolby Surround Pro Logic system?
Yes, you can use most of the new Dolby Digital program sources with your current playback system, because they incorporate Dolby Digital decoders and provide conventional analog stereo outputs. However, with many DVD-Video players, digital cable set-top boxes, and other sources, you need a separate multichannel Dolby Digital decoder to experience the thrilling 5.1-channel surround sound used on many Dolby Digital programs.
4. What is '5.1-channel' Dolby Digital?
At the option of their producers, Dolby Digital programs can deliver surround sound with five discrete full-range channels (left, center, right, left surround, and right surround) plus a sixth channel for those powerful low-frequency effects (LFE) that are felt more than heard in movie theaters. As it needs only about one-tenth the bandwidth of the others, the LFE channel is referred to as a '.1' channel (and sometimes erroneously as the 'subwoofer' channel). See question 14 for further information on speakers, including subwoofers.
5. How does 5.1-channel Dolby Digital differ from Dolby Surround?
5.1-channel Dolby Digital provides two surround channels to Dolby Surround's one for more precise localization of sounds and a more convincing, realistic ambiance. Also, the surround channels cover the entire audible range (20 Hz ® 20,000 Hz), whereas the range of Dolby Surround's single surround channel is limited (100 Hz ® 7,000 Hz). This further heightens realism and gives sound mixers more creative freedom.
In addition, Dolby Digital's multiple discrete channels enable more sharply-delineated spatial effects, and its '.1' LFE track makes it possible to reproduce low bass effects with stunning impact (twice as loud as the other channels).
6. Does 5.1-channel Dolby Digital make Dolby Surround obsolete?
No, Dolby Surround will be with us for as long as stereo is with us. This is why all Dolby Digital decoder units also incorporate a digitally-implemented Dolby Surround Pro Logic decoder.
Dolby Surround encodes four sound channels (left, center, right, surround) onto the two tracks of any conventional stereo program source. Dolby Digital soundtracks, on the other hand, can be carried only by Laserdiscs and new formats such as DVD and DTV.
Dolby Surround-encoded programs can be played back in mono, stereo, or with a Dolby Surround Pro Logic decoder that recovers the four original channels. Dolby Surround sources include regularly-scheduled TV programs (over a hundred in the U.S.), plus sports and special events; a growing number of video games, CD-ROMs, and music CDs; and broadcasts, tapes, and discs of thousands of movies.
7. Can I hear 5.1-channel Dolby Digital programs over a regular stereo or Dolby Surround Pro Logic system?
Yes. All Dolby Digital decoders, whether 5.1-channel or two-channel, have a unique feature called 'downmixing' that assures full compatibility with any playback system. At your option, the decoder will create 'on the fly' from 5.1-channel programs a two-channel, Dolby Surround-encoded mix for playback over a home theater system with Dolby Surround Pro Logic decoding; a two-channel stereo mix for regular stereo and headphone playback; or a mono mix for playback over a mono TV set.
This makes it possible for producers of 5.1-channel programs to provide only the one 5.1-channel mix on the disc or other source. The decoder in the playback system does the rest, automatically conforming the signal to the particular playback circumstances. Note: downmixing is not used for laser discs because they contain three different soundtracks: stereo PCM for a conventional stereo or Dolby Surround mix; one FM track for a mono mix; and one FM track for a 5.1-channel Dolby Digital mix. Frequently these mixes are prepared at different times, even by different mixers, so can sound quite different from each other.
8. Do all Dolby Digital programs provide 5.1 channels?
No, Dolby Digital soundtracks can provide anything from mono to full 5.1-channel surround sound. DVD- Video discs of movies can even carry multiple versions of the soundtrack that differ in the number of channels. A disc might contain a 5.1-channel sound mix with the dialogue in one language, a Dolby Surround-encoded two-channel mix in another language, and a mono track with the directors' comments or other supplementary information. The default soundtrack will vary from disc to disc, so always check the DVD disc's Language menu for the choices offered.
9. Do all DVD-Video discs have Dolby Digital soundtracks?
Discs in countries such as the U.S. that use the NTSC broadcast TV standard must provide at least one soundtrack in either of two formats: Dolby Digital or PCM (the format used on CDs). In countries using the PAL TV standard, including much of Europe, the discs must include at least one soundtrack in any one of three formats: Dolby Digital, PCM, or MPEG. As a result of these requirements and the options they permit, not all discs have Dolby Digital soundtracks.
Dolby Digital, however, is the only universal multichannel standard, and every DVD player sold worldwide incorporates Dolby Digital decoding. Therefore the vast majority of discs do include at least one Dolby Digital soundtrack.
10. How can I determine the soundtrack's format?
The Dolby Digital logo on a DVD-Video Disc or other program source indicates that it has one or more Dolby Digital-encoded soundtracks, but it does not indicate the number of channels. To help identify the latter, Dolby Laboratories is encouraging the use on program packaging of the channel-format symbols shown in Figure 10-1.
In addition, to prevent confusion at playback, data identifying the original production format of a program's soundtrack is incorporated right into the Dolby Digital signal. Some Dolby Digital decoder units use this data to display on the control panel the type of soundtrack you're listening to.
11. Do all program sources with Dolby Digital decoding provide 5.1-channel sound?
As with Dolby Digital program material, 'Dolby Digital' on a component such as a DVD player indicates that it incorporates Dolby Digital decoding, but not the number of channels.
Many program sources, including all DVD players and digital cable set-top boxes, provide a built-in, two -channel Dolby Digital decoder with analog stereo outputs (see question 7). For 5.1-channel playback, most units have a separate digital output that provides the undecoded Dolby Digital signal (data stream) for connection to an external unit, such as an A/V receiver, that has its own 5.1-channel Dolby Digital decoder.
Some DVD players do provide a built-in Dolby Digital 5.1-channel decoder with multiple analog outputs that can be connected directly to a 'Dolby Digital-ready' receiver, as described in question 12, for 5.1-channel sound. However, you will not be able to use the internal Dolby Digital decoder for other program sources, and these players don't offer the full range of options provided by external Dolby Digital decoder units. On the other hand, they are an inexpensive way to upgrade to 5.1-channel Dolby Digital initially, and provide a digital output so that you can later bypass the built-in decoder and use an external one.
12. How do I convert my current Dolby Surround Pro Logic system to 5.1-channel playback?
If your current system consists of separate audio components, you will need a 5.1-channel Dolby Digital decoder and a six-channel preamplifier (available separately or combined in one convenient unit). The preamplifier's outputs will plug into your existing power amplifiers.
If you have an older, integrated A/V receiver with Dolby Surround Pro Logic that does not provide external inputs to its built-in amplifiers, you have two choices. You can replace it with a new receiver incorporating a 5.1-channel Dolby Digital decoder, or add an external Dolby Digital decoder unit that includes center, left surround, and right surround amplifiers to use in place of those in your receiver (which will continue to power the left and right front speakers).
If you have a newer 'Dolby Digital-ready' A/V receiver with multichannel connectors for an external Dolby Digital decoder, you can add a decoder anytime, using the receiver's built-in Dolby Surround Pro Logic decoder in the meantime for satisfying home-theater sound. You can also connect the multichannel outputs of a DVD-Video player that has built-in 5.1-channel Dolby Digital decoding to this kind of receiver. An external decoder is still needed, however, for other Dolby Digital program sources (see question 11).
Note: be sure that the new decoder unit has a sufficient number of digital inputs to accommodate all the Dolby Digital program sources you expect to use (DVD-Video player, digital cable set-top box, digital TV receiver, etc.) Also, if you plan to play Dolby Digital laser discs, be sure that the unit also includes the necessary RF demodulator (only Laserdiscs require this feature; see question 24).
13. Will I still be able to play Dolby Surround program material?
Yes, all Dolby Digital decoders include Dolby Surround Pro Logic decoding, so you can continue to enjoy Dolby Surround-encoded programs after converting your system.
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14. Can I use my current speakers?
Yes, you can use your current speakers, because the configuration for Dolby Digital's five main channels is essentially the same as that for Dolby Surround Pro Logic.
A unique feature called Bass Management lets you route low bass sounds to those speakers in your system that are best able to reproduce them. For example, you might wish to route the LFE signals to the front left and right speakers, if they have full bass capabilities, or to a separate subwoofer. You can also redirect the surround channels' low bass, and so continue to use the limited-bandwidth surround speakers you got for Dolby Surround Pro Logic playback. Or you could use small satellite speakers for the five main channels and route all bass to a subwoofer. You could even go so far as to add a subwoofer to each main channel.
For information on speaker placement, click here . This information can also be found on page 6 of the booklet 'Dolby Surround: The Sound of Home Theater' published by Dolby Laboratories.
15. What kind of speakers should I get for an all-new Dolby Digital system?
The ideal Dolby Digital playback system uses identical full-range speakers for the left, center, right, and each surround channel. If this is impossible, be sure that the overall tonal characteristic, or timbre, of all the speakers is similar. This is equally important for both Dolby Surround Pro Logic and Dolby Digital playback.
Most speaker manufacturers offer timbre-matched home theater speakers. Many also offer systems combining matched compact speakers for the five main channels with one or more separate subwoofers for the non-directional bass; such a 'satellite' system can prove an effective, space-saving solution.
16. Should I use bipolar, dipolar, or tripolar surround speakers?
Surround speaker placement, room acoustics, and personal preference are as important as the speakers' radiating characteristic. These factors vary greatly, so Dolby Laboratories cannot recommend a particular speaker for home theater use.
Bipolar, dipolar, and tripolar surround speakers use speaker drivers aimed towards the front and back of the room to achieve a diffuse soundfield like that created by the multiple surround speakers used in movie theaters. Your room's acoustics will effect these designs more than conventional direct-radiating speakers, which, when placed properly, can also make effective surround speakers.
17. My new Dolby Digital decoder has a multi-pin 'DB-25' connector, but my audio components only have phono connectors. What do I do?
The DB-25 interface was developed by Lucasfilm THX to save space on the rear panels of home theater products. If your components use a mix of connectors, cables with a DB-25 (25-pin) connector on one end and multiple phono connectors on the other are available from home theater equipment retailers.
18. My DVD player has two digital outputs, one optical and one coaxial, and my Dolby Digital decoder has both kinds of inputs. Which should I use?
Under most conditions, optical and coaxial digital connections work equally well. Under some rare circumstances, however, coaxial cables, particularly very long ones, can pick up radio frequency (RF) interference generated by household appliances, or nearby high-tension power lines or broadcast towers.
If cost is a consideration, start with coaxial, which is less expensive. If you then hear RF interference, you can try relocating the cables, moving your components closer together so you can use shorter cables, or, if all else fails, changing to costlier optical cable. If cost is no object, using high-quality optical cables from the outset is probably your best long-term choice.
Note: some DVD players and Dolby Digital decoders have either a coaxial or an optical connector. Be sure that the units you purchase both use the same type.
19. Why does my Dolby Digital decoder provide time delays?
Because the surround speakers in a home theater system are usually closer to viewers than the front speakers, both Dolby Digital and Dolby Surround Pro Logic playback require a split-second electronic delay of the surround channels.
In the case of Dolby Digital, the delay ensures that the viewer hears sound from the surround and front speakers simultaneously. For Dolby Surround Pro Logic, which has less inherent channel separation than Dolby Digital, a slightly longer (by 15 milliseconds) delay ensures that sound from the surrounds arrives just after sound from the front. This delay reduces the audibility of sound leakage from the front to the surround speakers.
Some Dolby Digital decoder units also provide an adjustable center-channel delay to ensure that the viewer hears sound from all three front speakers simultaneously.
20. How to I set the surround time delays?
The time delays in your Dolby Digital decoder are preset to provide good results in most home theater installations. If you wish to fine-tune the adjustments, consult the decoder's instruction manual.
Most units allow you to adjust the surround delay in either the Dolby Digital or Dolby Surround Pro Logic mode. Because the relationship between the two delays is fixed, you only need to set the delay in one mode. The decoder will automatically provide the appropriate delay whenever you switch to the other mode.
To establish the proper surround delays for your system, you need to know the distances between your viewing position and a front speaker (A) and a surround speaker (B) as shown in Figure 20-1. Then find the distance to the surround speaker on the graph's vertical axis, and the distance to the front speaker on the horizontal axis. Lines drawn from these points will intersect on the graph at the recommended delay setting.
21. How do I set the center channel time delay?
You need no center delay (set it at '0') if your seating area is small with a few viewers at any time, and if you can place the three front speakers equidistant from it. If the center speaker must be placed more in line with the left and right speakers, thereby bringing it closer to the viewers than the left and right speakers, add 1 ms of delay for each foot it is closer. For example, if the distance to the Center channel speaker is one foot less than L or R, set the time delay to 1 ms.
If your seating area is wide, with several viewers in a row as in a movie theater, it's best to place the left, right, and center speakers all in line and use no center time delay.
Finally, if it is necessary to place the center speaker further back than the left and right speakers (not illustrated), select '1 ms' (for a one foot difference) delay or '2 ms' (two feet) delay, if these options are provided. If they are not provided, use '0' delay.
22. What is the 'Midnight Mode' on my new Dolby Digital A/V receiver?
Dolby Digital soundtracks can have a very wide dynamic range between soft and loud sounds. At a full playback level, this can be thrilling, providing a truly theatrical experience, particularly for movies.
Late at night, however, the loud sound effects on movie soundtracks might not be appreciated by your family or neighbors. But if you turn down the volume to 'keep the peace,' the dialogue will be hard to hear, and subtle low-level effects may get lost altogether.
What you'd really like to do is turn down the volume on just the loud effects, turn up the volume on quiet sounds, and keep the dialogue at the same level. This is what a Dolby Digital feature called Dynamic Range Control does. For lower-level listening, it applies dynamic range compression that preserves low-level sounds, prevents dramatic passages from getting too loud, and keeps dialogue intelligible. To help explain its function, manufacturers of Dolby Digital decoders have come up with names like 'Midnight Mode' for this feature.
The amount of compression is not arbitrary, but is decided in advance by the soundtrack's producers, and coded right onto the soundtrack. For example, if there's a loud sound coming from the left surround that's meant to startle the audience, the soundtrack mixers might indicate less compression for that sound than other loud sounds when the Midnight Mode is switched on.
Some Dolby Digital decoders let you select various amounts of the available compression (e.g., 50%, 75%, 100%), while others provide only 100% when the compression mode is selected.
23. I'm tired of having to adjust the volume every time the program changes or I switch sources or TV channels. Can Dolby Digital help?
Yes. Conventional program sources often force you to readjust the volume when you change channels or play a different video. With Dolby Digital program sources, on the other hand, a feature called Dialogue Normalization lets you set playback volume and forget it.
Dialogue Normalization automatically adjusts the volume when you change Dolby Digital programs so that the level of the dialogue remains constant. It does not alter the dynamic range, only the overall playback level, based on data about the dialogue that is coded into the program signal.
With Dialog Normalization, you can 'channel surf' when watching digital TV without having to adjust the volume each time you change channels. Those extra-loud commercials will be tamed. And you can play an evening's worth of DVD-Video discs without ever touching the volume control.
24. What equipment do I need to play Dolby Digital Laserdiscs?
Dolby Digital Laserdisc players do not have a built-in Dolby Digital decoder; they output the Dolby Digital data stream from Laserdiscs on a radio-frequency (RF) carrier that requires demodulation prior to Dolby Digital decoding. If you wish to play the Dolby Digital soundtrack, therefore, be sure that the disc player has a 'Dolby AC-3 RF' output and your Dolby Digital decoder unit includes an RF demodulator specifically for laser disc use. Not all decoder units provide the demodulator, because no other Dolby Digital program source, including DVD, requires it.
If you have an older laser disc player and don't want to decode the Dolby Digital tracks on newer discs, they will play perfectly well on your older player. On laser discs, the Dolby Digital track is encoded on what used to be the right FM analog track, leaving the standard PCM digital stereo tracks intact for conventional stereo and Dolby Surround Pro Logic playback. The left FM analog track may contain a mono version of the soundtrack, commentary, or other material.
One final note: laser discs with 5.1-channel Dolby Digital soundtracks were originally identified as Dolby Surround AC-3, 'AC-3' being the technical term for the digital audio coding upon which Dolby Digital is based. Today the simpler term 'Dolby Digital' is used instead to identify laser discs, like other formats, that have Dolby Digital soundtracks.
25. What equipment do I need to receive satellite broadcasts with 5.1-channel Dolby Digital sound?
To receive the 5.1-channel soundtrack on programs such as the Dolby Digital-encoded theatrical films broadcast by DIRECTV on its pay-per-view channels, you need a new satellite receiver that provides a Dolby Digital output (the 'Digital' output on conventional satellite receivers does not handle Dolby Digital signals). As with other Dolby Digital components, you connect the Dolby Digital coaxial or optical output to a digital input on your Dolby Digital decoder unit.
Standard stereo audio, usually Dolby Surround-encoded, is broadcast simultaneously, so you need a new satellite receiver only if you wish to receive the Dolby Digital soundtrack.
26. How can I receive high-definition (HD) satellite TV transmissions with Dolby Digital sound?
To receive high-definition programming transmitted via satellite, you will need an HD satellite receiver, and a new, larger dish. Most receivers are equipped like most DVD-Video players, that is, with a built-in, two-channel Dolby Digital decoder with analog stereo out puts, and a Dolby Digital output for 5.1-channel sound with an external 5.1-channel Dolby Digital decoder unit.
27. Can I use my Dolby Digital home theater system for the new digital TV broadcasts?
Yes, you can: whether high-definition (HDTV) or standard-definition (SDTV), all digital television (DTV) broadcasts use Dolby Digital audio in the U.S., Canada, and other countries that have adopted the ATSC television standard ( www.atsc.org ). Dolby Digital audio is also used in some countries like Australia in conjunction with other transmission standards.
Like other Dolby Digital program material, the audio format of DTV broadcasts varies from mono to full 5.1-channel surround sound. Because most TV facilities have to gear up for multichannel audio production and distribution, many DTV programs are being broadcast initially in two-channel Dolby Digital (some-times Dolby Surround-encoded for four-channel playback with Dolby Surround Pro Logic decoding). Movies prepared with 5.1-channel Dolby Digital soundtracks for theatrical release are the primary source of multichannel Dolby Digital DTV programming initially.
DTV sets and tuners also vary with respect to the number of audio channels they provide. Some have built-in two-channel Dolby Digital decoders, while others have 5.1-channel Dolby Digital decoders for connection to a Dolby Digital-ready A/V receiver (see question 12). Others include not only Dolby Digital decoding but also amplifiers and speakers.
Most DTV receivers have a separate digital output that provides the undecoded Dolby Digital signal for connection to your A/V receiver or other unit with 5.1-channel Dolby Digital decoding. As a result, you can add a DTV receiver to your Dolby Digital home theater system at any time, without fear of obsolescence or costly equipment duplication.
28. How can I receive digital cable programs with Dolby Digital sound?
Digital cable television systems can provide you with another source of programming for Dolby Digital playback. The number of channels with Dolby Digital cable transmissions varies as with DTV broadcasts and other Dolby Digital program sources. All digital cable set-top boxes incorporate a two-channel Dolby Digital decoder with stereo analog outputs for compatibility with conventional stereo and home theater systems, and fully-compliant units also provide a digital output for connection to your A/V receiver or other unit for 5.1-channel playback with an external multichannel Dolby Digital decoder.
29. Can I purchase DVD-Video discs with Dolby Digital soundtracks in Europe?
Yes, Dolby Digital audio is used on DVD-Video discs throughout the world (see question 9). A word of caution, though: while the audio and video technical standards are the same for DVD-Video worldwide, discs purchased in one part of the world may not play at all in another part of the world due to 'regional coding.'
Regional coding was developed at the behest of the film industry, which often releases videos of movies in North America before they've even reached movie theaters in other parts of the world. Discs released in a market like North America (Region 1) can be coded to play only on players manufactured for that market. Take a Region 1-coded disc to another part of the world, and it won't work in the players manufactured for that market. Some discs, on the other hand, are coded as Region 0, meaning they will play on all DVD players in all regions. Check the packaging to find out if the disc has any regional limitations.
30. I'm thinking about getting a PC with a DVD-ROM drive. Will it give me 5.1-channel Dolby Digital?
That depends on the computer's configuration and its DVD/audio card, so check the specifications carefully to be sure you get the audio capability you want.
Most PCs can be connected to external playback equipment ranging from amplified stereo speakers to a full 5.1-channel playback system. The latter include not only full home theater systems, but compact, multichannel PC speaker systems incorporating amplifiers and Dolby Digital and/or Dolby Surround Pro Logic decoding. PCs bundled with stereo amplifiers and speakers may have a built-in two-channel Dolby Digital decoder for the DVD-ROM player that will downmix 5.1-channel soundtracks.
Audio outputs possible on PCs include analog power amplifier outputs, line level outputs for external amplifiers, headphone jacks, and RF carriers. They may also provide conventional PCM digital audio outputs, and/or outputs that provide the undecoded Dolby Digital data stream via S/PDIF (IEC 1937), USB, IEEE 1394, LAN, wireless link, or other format connections.
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31. I've heard about surround-sound systems that use only two speakers. Do they really work?
Thanks to the increasing power and dropping cost of signal-processing chips, sound that appears to come from around the listener is now possible with just two speakers.
These audio processing systems, often referred to as 'virtual surround,' require that the listener be positioned in a specific 'sweet spot' in front of the two speakers. As a result, they cannot substitute for multiple speakers in home theater applications. But for PCs, where a single user is seated directly in front of the monitor, they can provide a cost-effective alternative to a full, multi-speaker surround setup.
There are two fundamental approaches to 'virtual surround.' Some systems take any stereo program source and create what might be called a 'pseudo-surround' effect. The results are inconsistent, however, and can create effects not at all intended by the program producers. The other approach has been developed by Dolby Laboratories to reproduce the actual surround information recorded on multichannel Dolby Surround and Dolby Digital program material, for a more accurate and consistent listening experience.
Called Virtual Dolby Surround and Virtual Dolby Digital, these processes start by decoding, respectively, the original four or 5.1 channels of the program material. The center channel is then divided equally between the left and right speakers to create a phantom center image, while the surround signals are processed by a 'virtualizer' circuit and mixed in with the main left and right channel signals. The virtualizer processor adds cues to the surround signals based on how we identify a sound's directionality, thereby creating virtual surround images from just two speakers. Unlike a multi-speaker home theater system, the center and surround effects are affected only by the listener's position relative to the two speakers, and not by room acoustics.
Dolby offers its own virtualizer technique, and also tests and approves other virtualizers for use in combination with Dolby Surround Pro Logic and Dolby Digital decoding to create Virtual Dolby Surround and Virtual Dolby Digital. Approved technologies include 3D Phonic, Virtual Sonic, VMAx, A3D, Qsurround, N-2-2 DVS, TruSurround, Sensaura, RSX, and Incredible 3D Surround.
Products with Virtual Dolby Surround and/or Virtual Dolby Digital include DVD players, PC/DVD packages, television sets, and multimedia speaker systems.
32. Does Dolby plan to introduce higher and not on proper listening tests.
To understand what's going on with respect to Dolby Digital and competing systems, you first need to know something about 'perceptual' digital audio coding.
Conventional pulse-code modulation (PCM) digital audio, like that on CDs, takes up a lot of storage and transmission space³so much so that multiple channels of PCM for surround sound are usually impractical, particularly if the medium has to carry coding systems). A complex scheme or algorithm based upon psychoacoustics, the science of how we perceive sound, selects which data is to be transmitted and which is to be discarded.
With Dolby Digital, a 5.1-channel program requires less than one-tenth the data of just one channel of the PCM audio used for CDs. Some competing systems such as DTS operate at higher, less efficient data rates, and their proponents imply that by definition they must sound better than Dolby Digital.
The data rate of a digital coding system, however, does not in itself define its sound quality; the coding algorithm is equally, if not more, important. Dolby Digital's algorithm, technically known as Dolby AC-3, is based upon Dolby Laboratories' decades of research into how we perceive sound. As a result, Dolby Digital achieves very high sound quality at the low data rates necessary for uncompromised picture quality on such formats as DVD-Video discs.
Before selecting Dolby Digital as the audio standard for new formats such as DTV, panels of critical listeners compared various perceptual coding systems not to each other, but to original master recordings. Differences between the masters and their Dolby Digital counterparts were judged insignificant enough to choose Dolby Digital as the standard. Dolby Laboratories has conducted similar comparisons for audio professionals, with much the same result.
34. Don't some products now incorporate DTS decoding?
Yes, a number of A/V receivers and decoder components now incorporate DTS as well as Dolby Digital decoding. However, the total population of DTS decoders is comparatively small, given that Dolby Digital is also included in many millions of DVD- Video players, set-top boxes, and other products.
Most importantly, program material with DTS-encoded soundtracks is rare, and likely to remain so. Programming with Dolby Digital-encoded soundtracks, on the other hand, is plentiful, and more is becoming available all the time.
One reason for the abundance of Dolby Digital programming is that Dolby Digital is the audio standard for media such as DTV. Also, for DVD-Video, Dolby Digital is what's called a 'mandatory' audio coding format, meaning that a Dolby Digital soundtrack can be the only one on a disc. DTS, by comparison, is an 'optional' coding format, meaning that the disc must have a mandatory-format soundtrack as well. Because providing both soundtracks on a disc would make it impossible to provide such features as multiple-language versions of the soundtrack, or necessitate lower picture quality, few DVD producers are likely to take the DTS route.
Another advantage of Dolby Digital is its wide-spread adoption by the movie industry. More than three times as many films have been released in Dolby Digital than in any other digital format, providing a vast library of titles readily available for release in Dolby Digital consumer formats.
A final advantage that keeps the list of Dolby Digital programs growing is that hundreds of facilities throughout the world have been equipped to produce them. Dolby Laboratories manufactures a range of professional encoding and decoding equipment for this purpose, licenses providers of DVD disc-authoring systems, and regularly conducts seminars in multichannel audio production, distribution, and broadcasting for audio professionals.
35. Will Dolby provide 5.1-channel music CDs?
Nobody is more enthusiastic about multichannel sound than Dolby Laboratories. However, we also recognize the importance of standardization, compatibility, and the reluctance of producers to release, and retailers to stock, more than one version of a given program. As a result we will not release CDs with Dolby Digital soundtracks, or encourage others to do so.
5.1-channel music CDs, such as those released by DTS, are non-standard; they don't provide the PCM audio specified by the CD 'Red Book.' They are also incompatible in that they cannot be heard at all without a special external decoder, and in many cases require a specially-equipped CD player as well.
Newer formats like DVD-Video discs, on the other hand, have been developed from the outset to support multichannel digital audio. For compatibility, these new formats can, if necessary, carry more than one kind of soundtrack. In addition, as explained in question 7, sources with Dolby Digital soundtracks are inherently compatible with mono, stereo, and Dolby Surround Pro Logic playback systems.
For older stereo formats, including CD, there's tried-and-true Dolby Surround, a fully compatible format enabling two-channel soundtracks to be encoded with four-channel surround sound (see question 6). Among the program sources encoded with Dolby Surround are more than 700 CD titles.
When it comes to music-only recordings with multichannel digital audio, a new kind of DVD disc called DVD-Audio has been developed (see question 36).
36. Can I play the new DVD-Audio discs on my DVD-Video player or my computer's DVD-ROM drive?
Like DVD-Video discs, the new DVD-Audio discs can carry a variety of soundtracks, with mono, stereo, or multichannel sound, using different forms of audio coding. Dolby Digital is an optional coding format for DVD-Audio, and those discs that use it will play on any DVD-Video player and on any DVD-ROM drive with Dolby Digital decoding.
Otherwise, you'll need a new player to enjoy the multichannel sound from DVD-Audio discs recorded in very high-resolution PCM audio, or a new kind of coding called MLP (Meridian Lossless Packing) that saves disc space not by eliminating data, but by storing it more efficiently. These formats require new kinds of digital decoding that is included in DVD-Audio players and 'combi' DVD players designed to play both audio and video DVD discs.
Dolby and the double-D symbol are registered trademarks of Dolby Laboratories Licensing Corporation. Any other trademarks used are the property of their respective owners
When it matters
5.1 passthrough is only useful when you have the following:
- A 5.1 speaker system with an HDMI ARC or digital optical input.
- At least one source device capable of outputting a 5.1 audio signal.
Note that some TVs can only pass 5.1 through over a certain connection (either digital optical or HDMI ARC), and some can only pass through certain signal types (DTS or Dolby Digital), so make sure you pick a TV that supports both the connection and signal type you wish to use.
If you use the TV’s speakers, or just use a 2.0 (two speakers) or 2.1 (two speakers + one subwoofer) sound system, you don’t need to worry about 5.1 passthrough.
And keep in mind that 5.1 passthrough isn’t a necessity. This image is an example of a 5.1 surround sound setup with a TV that doesn’t support passthrough.
In short, 5.1 passthrough is just an option that allows you to get surround sound for multiple source devices, with few cables.
Here are a couple of examples of home entertainment setups that take advantage of a TV's 5.1 audio output and passthrough.
Our tests
DTS 5.1 passthrough via digital optical
DTS 5.1 passthrough via digital optical capability means a TV can accept a DTS 5.1 signal from a source device, and then pass that along to the receiver over a digital optical cable. DTS is pretty much only found on DVDs and Blu-rays, so it’s only useful for those media. This is only really an important test if you want to do this exact connection and transfer in your setup.
To test for DTS passthrough via optical, we connect a Blu-ray player to our TV via HDMI and play the 5.1 audio test found on the Spears & Munsil HD Benchmark and Calibration Disc (2nd Edition), outputted via DTS 5.1. We then output the TV’s audio to our 5.1 receiver via digital optical and see whether the receiver receives a 5.1 signal, or if it is downgraded to 2.1.
DTS 5.1 passthrough via HDMI ARC
DTS 5.1 passthrough via HDMI ARC capability means a TV can accept a DTS 5.1 signal from a source device, and then pass that along to the receiver via an HDMI ARC connection. This is only really an important test if you want to do this exact connection and transfer in your setup.
To test for DTS 5.1 passthrough via HDMI ARC, we connect a Blu-ray player to our TV via HDMI and play the 5.1 audio test found on the Spears & Munsil Calibration Disc, outputted via DTS 5.1. We then output the TV’s audio to our 5.1 receiver via HDMI ARC and see whether the receiver receives a 5.1 signal, or if it is downgraded to 2.1.
Dolby Digital 5.1 passthrough via digital optical
Dolby Digital 5.1 passthrough via digital optical capability means a TV can accept a Dolby Digital 5.1 signal from a source device, and then pass that along to the receiver over a digital optical cable. Dolby Digital is found on DVDs, Blu-rays, most streaming media, and even some TV channels, so it’s useful for a variety of sources. This is only really an important test if you want to do this exact connection and transfer in your setup.
To test for Dolby Digital 5.1 passthrough via digital optical, we connect a Blu-ray player to our TV via HDMI and play the 5.1 audio test found on the Spears & Munsil Calibration Disc, outputted via Dolby Digital 5.1. We then output the TV’s audio to our 5.1 receiver via digital optical and see whether the receiver receives a 5.1 signal, or if it is downgraded to 2.1.
Dolby Digital 5.1 passthrough via HDMI ARC
Dolby Digital 5.1 passthrough via HDMI ARC capability means a TV can accept a Dolby Digital 5.1 signal from a source device, and then pass that along to the receiver over an HDMI ARC connection. This is only really an important test if you want to do this exact connection and transfer in your setup.
To test for Dolby Digital 5.1 passthrough via HDMI ARC, we connect a Blu-ray player to our TV via HDMI and play the 5.1 audio test found on the Spears & Munsil Calibration Disc, outputted via Dolby Digital 5.1. We then output the TV’s audio to our 5.1 receiver via HDMI ARC and see whether the receiver receives a 5.1 signal, or if it is downgraded to 2.1.
Dolby Atmos via Dolby TrueHD passthrough via HDMI eARC
Dolby Atmos via Dolby TrueHD passthrough via HDMI eARC capability means a TV can accept a Dolby Atmos signal from a source device, when Dolby TrueHD is used as the carrier signal, and then pass that along to the receiver over an HDMI eARC (Enhanced ARC) connection. This is only really an important test if you want to do this exact connection and transfer in your setup.
To test for Dolby Atmos via TrueHD passthrough via eARC, we connect a PC to the TV via HDMI and play a Dolby Atmos via TrueHD test file (mkv video) using the MPC-HC media player software, set to bitstream audio. We then output the TV’s audio to our 5.1.2 receiver via HDMI eARC and see whether the receiver receives a Dolby Atmos via TrueHD signal, or if it is downgraded to normal Dolby Digital.
DTS:X via DTS-HD MA passthrough via HDMI eARC
DTS:X via DTS-HD MA passthrough via HDMI eARC capability means a TV can accept a DTS:X signal from a source device, when DTS-HD MA is used as the carrier signal, and then pass that along to the receiver over an HDMI eARC (Enhanced ARC) connection. This is only really an important test if you want to do this exact connection and transfer in your setup.
To test for DTS:X via MA passthrough via eARC, we connect a PC to the TV via HDMI and play a DTS:X via MA test file (mkv video) using the MPC-HC media player software, set to bitstream audio. We then output the TV’s audio to our 5.1.2 receiver via HDMI eARC and see whether the receiver receives a DTS:X via DTS-HD MA signal, or if it is downgraded to normal DTS.
Additional information
5.1 surround sound setup
‘5.1’ is the typical surround sound setup, and involves five (5) ‘regular’ speakers, and one subwoofer (which is the ‘.1’ in '5.1').
The speakers are ideally positioned as follows.
In front: One speaker to the left of the TV, one in the center (either just above or just below the screen), one to the right. For the most part, these handle dialogue and the sound of onscreen action.
To the sides: One speaker each to the left and right of the seating area. These are mostly for playing sound from action occurring to the side and rear of the camera’s point of view.
Subwoofer: Should be placed on the floor to the side of the TV. Plays deep bass.
All six speakers receive and play their own unique audio channel, and having five speakers in different places, each playing different sounds, adds a sense of space and direction to the audio that you would not get with stereo setup (2.0).
![Dolby Digital Sound Dolby Digital Sound](https://www.pcper.com/images/reviews/200/XtremSoundDDL_lrg.gif)
You also benefit from having a dedicated subwoofer, as that provides deeper bass than you would get from regular speakers.
How 5.1 surround sound passthrough works
In a typical setup, multiple source devices will be connected to the TV via HDMI, a cable which can transmit both video and audio. With 5.1 passthrough, instead of needing to connect a separate wire from each source to the AV receiver in order for the audio signal to make it to the receiver, a single audio connection is established between the TV and the receiver. The 5.1 audio signal is transmitted via the existing HDMI connection from the sources and into the TV and then sent by the TV down the audio output and to the receiver.
Depending on the number of sources you have, and whether they all support the 5.1 signal types you want to use, this kind of setup can eliminate several extra cables, and without noticeable impact on sound quality.
5.1 surround sound signal types
There are several different kinds of audio encoding used to deliver surround sound in a video. The three most common are Bitstream formats called Dolby Digital and DTS, which are both compressed, and then PCM, which is uncompressed.
Bitstream
Bitstream audio is compressed, meaning information that is deemed less important to the sound is removed from the signal. This does reduce the quality somewhat, but it’s important to note that compressed audio still sounds very good – good enough that the average person is not going to hear much difference between it and uncompressed audio.
With Bitstream, the audio signal (basically instructions telling the speakers what to do) is encoded (packaged) by the source device, and then sent to be decoded (unpacked) by the receiver, with the resulting information then telling the speakers what they are meant to play. This delivery method makes for a smaller signal size, and so it is easier to send multiple channels of audio. It also means that a receiver needs to have the ability to decode a particular Bitstream audio format in order to play it. Without that ability to decode the signal, a receiver will not be able to unpack and play a given Bitstream audio signal.
At present, you must use a Bitstream signal if you wish to pass 5.1 audio through a TV. You can do this both via HDMI ARC and digital optical.
There are two main kinds of Bitstream signals. There is Dolby Digital 5.1, which is a very common audio format, found on DVDs, Blu-rays, and most streaming media, and is a bit more heavily compressed. The other is DTS, which is also a common audio format and is also found on most DVDs and Blu-rays. It is very uncommon with streaming media, though. It isn’t quite as compressed as Dolby Digital.
When to use DTS & Dolby Digital
You need to use either DTS or Dolby digital in order to pass a 5.1 signal through a TV. While DTS is somewhat preferable in terms of audio quality, Dolby Digital is more widely available.
- Use DTS in your setup if you only watch Blu-rays or DVDs.
- Pick Dolby Digital if you also watch streaming videos. Output audio directly from each source device and to the receiver. Output this audio via HDMI, and not optical.
PCM
PCM is an uncompressed audio format, which means it will theoretically have the best overall sound quality, as no information has been removed to facilitate transmitting the signal. PCM is sent unencoded by the source, meaning the full, unpacked ‘instructions’ for what sounds to play are sent directly from the source to receiver, and then on to the speakers.
Unfortunately, this makes for a signal that is more difficult to transmit. No TV seems to be able to pass a 5.1 PCM signal through to a sound system, so sending a PCM signal to or from a TV will downgrade the signal to 2.1 (two speakers + one subwoofer), thus eliminating the extra channels necessary for surround sound.
PCM 5.1 can work with a receiver that supports the format, so if you want uncompressed sound, you’ll need to forego passing the audio through your TV, and instead output the sound directly from the source (one that outputs PCM 5.1) to the receiver. Note that only HDMI can transmit a 5.1 PCM signal. Digital optical is only capable of transmitting a 2.1 or 2.0 PCM signal.
When to use PCM
For 5.1 audio, use PCM sound only if you
- Output audio directly from each source device and to the receiver.
- Output this audio via HDMI, and not optical.
How to get the best results
Here are the steps you need to complete to enable 5.1 passthrough on compatible TVs.
- Samsung:
- Go to Menu > Sound > Speaker List and select ‘Receiver (HDMI)’ for HDMI ARC, or ‘Audio Out/Optical’ for digital optical.
- Go to Menu > Sound > Additional Settings and set ‘HDMI Audio Format’ to ‘Bitstream.’
- Go to Menu > Sound > Additional Settings and set ‘Audio Format’ to either ‘Dolby Digital’ or ‘DTS.’
- For HDMI ARC, go to Menu > General and enable ‘AnyNet+.’
- Sony:
- Go to Settings > Sound > Speakers and select ‘Audio System.’
- Go to Settings > Sound > Digital Audio Out and select ‘Auto 1’
- For HDMI ARC, enabled ‘Bravia Sync Control.’
Dolby Digital Sound System For Home
- Vizio:
- Go to Menu > Audio > and set ‘TV Speakers’ to ‘Off.’
- Go to Menu > Audio > Digital Audio Out and select ‘Bitstream.’
- For HDMI ARC, go to Menu> System and set CEC to ‘Enabled.’
- LG (For most TVs with 5.1 passthrough):
- Go to Settings > Advanced > Sound > Sound Out and select ‘Audio Out (Optical/HDMI ARC).’
- For HDMI ARC, go to Settings > General > Simplink and set it to ‘On.’
Related settings
- CEC: To enable HDMI ARC, you typically also need to enable a feature called ‘CEC.’ This makes it so that some commands sent to the TV, receiver, or source device can result in instructions being relayed to one of the other devices. For example, with CEC, powering the TV on might also power on the receiver, or pressing the volume up/down buttons on the remote will adjust the receiver’s volume output. Just be aware that this sort of thing may start happening with your setup.
Other notes
- For HDMI ARC: Make sure the TV and the receiver/soundbar are both connected by their respective HDMI ARC ports.
- For Digital Optical: Make sure the cable is firmly connected to each device. It should make a clicking noise when it gets plugged in.
Conclusion
5.1 surround sound passthrough allows a TV to accept a 5.1 signal and then pass it along to a speaker system. It’s not the most important feature, but in some situations, it can help cut down on the number of cables required for a surround sound setup. We test whether each TV is able to receive and pass both Dolby Digital 5.1 and DTS 5.1 signals to a 5.1 receiver. We also test passthrough over HDMI eARC of the Dolby Atmos and DTS:X object-based formats.
Different TVs require different settings in order to enable 5.1 audio, and the requirements differ slightly for HDMI ARC and digital optical. If you want 5.1 passthrough, be sure to get a TV that supports the feature for the signal type you use, and then make sure your TV’s settings are such that they will allow the process to happen. Above, we list some of the steps required for the more common brands.