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post #1 of 5 Old 11-17-2015, 12:29 PM - Thread Starter
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The Official Dolby Surround & DTS Neural:X FAQ & Discussion Thread

What is Dolby Surround?

Dolby Surround is a spatial audio algorithm that creates a channel-based, three-dimensional sound scene from two or more input channels. The algorithm was designed to decode matrix encoded programs (Lt/Rt) but is also a stereo upmixer.

Why do most people refer to it as DSU?

The process of creating a higher channel count program from non-encoded content is commonly referred to as upmixing. With the implementation of Atmos for home use in receivers and pre/pro units, Dolby Surround has also become referred to as "Dolby Surround Upmixing" or DSU for short. The term "Dolby Surround" refers to both the encoding and decoding in the home environment, while in the theater it is known "Dolby Stereo", "Dolby Motion Picture matrix" or "Dolby MP".

Hasn't Dolby Surround been around for decades?

The new algorithm began being used in “Dolby Surround” products in 2014. The current technology has an entirely different set of features and processing from the 4-2-4 surround system (also called Dolby Surround) that was introduced in 1982. The original "Dolby Surround" home implementation omitted the center channel, and only up-mixed stereo to Surround 3.0 (Left, Right, Surround).

How does Dolby Surround work?

Input channel configurations with more than two channels are decomposed into channel pairs which are then processed independently. The term "decomposed" doesn't mean or should be inferred to mean degradation or diminution. Instead, it refers to a mathematical factorization of a matrix into a product of matrices.

How is Dolby Surround different than existing surround decoders?

First, Dolby Surround offers multi-band processing which allows for improved selectivity and separation of sounds. Second, there are independent processing for direct and diffuse (spread out) signal components and user adjustable decorrelation that allows for greater listener envelopment. Key to Dolby Surround is the separation of steered (direct) signals from diffuse signals in both time and frequency. The steered signal components can be accurately placed in a listening environment regardless of the listener's speaker configuration ("arbitrary output channel count and location"). While the diffuse signal content is spread to improve the sense of envelopment. Third, it supports any number of speakers including height and top configurations.

What is matrix-encoded versus stereo material?

Matrixing refers to the encoding of separate sound signals within a stereo source whereas stereo is the reproduction of sound using two or more independent audio channels. Of course, Dolby found a way to pack additional information in two channels in "Dolby Stereo". With Dolby Stereo, Left (L), Center (C), Right (R), and Surround (S) channels are matrixed into what Dolby calls Left-total (LT) and Right-total (RT). A traditional matrix encoder was supplied with a number of input channels, each corresponding to a specific speaker. The two channel (LtRt) output was formed by a linear matrix operation.

How is Dolby Surround encoding different from Pro-Logic?

One of the primary limitations of legacy matrix decoding systems such as Dolby Pro Logic and Pro Logic 2 is that they can only identify and pan a single sound source at any given time. Dolby Surround, on the other hand, operates in the frequency domain (the analysis of mathematical functions or signals with respect to frequency rather than time) allowing for improved signal separation as each analysis band can separate and spread a signal in a sound field or pan a sound source independently.

How does Dolby Surround independently separate and pan a sound source?

The answer is a bit complicated but basically Dolby Surround first transforms the incoming signal into the frequency domain before grouping it into 20 bands (multi-band processing). It then assigns 3 values, or statistical estimations, to the signal in each of those bands before converting them back to the time domain where they are separated into left and right steered and left and right diffuse signals. Using signal modelling, the steered signals are then sent to an appropriate speaker while diffuse ones, a left and right signal, are spread to all of them including top surround channels. Also, so that the diffuse sound isn't exactly the same in each of the speakers, three additional signals are created all with frequency dependent delays so that lows are delayed more than highs.

How does Dolby Surround work with multi-channel sources?

Side and rear surround channels can be created from a 5.1 mix by simply specifying the correct output configuration that mimics the positions of the side surround and rear surround channels. For top speakers, Dolby Surround can be used to extract ambient or diffuse information from the input signals and steer it toward the top surround channels. Where two top speaker configurations, the diffuse signal from both the left and right channels as well as the diffuse signal from left and right surround channels can be combined. Where there are four top speakers, the diffuse signals can be combined or kept separate. If kept separate, then the top front receive only left and right ambience and the top rear only receive the left and right surround ambience.

Does Dolby Surround sound better than Pro Logic II?

Dolby conducted subjective testing using matrix encoded 5.0 surround sound sources in a 5 speaker configuration using the original multi-channel program as the reference signal. A variety of source material was demonstrated including from the show "24", Lord of the Rings, the San Francisco Symphony, Time Skipper (this title is unclear but perhaps is in reference to "Time" from Show Banga feat. Kool John & Skipper or "Time Goes By" by Carrie Skipper), Titanic, Sweet Emotion, applause, and from a Superbowl. LFE signals, if present in the original program, were deleted. The results were that listeners preferred (there was statistical difference in favor of) Dolby Surround with nearly all the material except the applause. There was little difference measured with the upmixing of Sweet Emotion though it appears to be slightly higher in favor of Dolby Surround.

* Please PM me with any needed corrections along with a link to or description of your source.

What is DTS Neural:X?

A spatial remapping algorithm included in DTS:X to adapt 5.1 and 7.1 content to any immersive speaker layout. The renderer uses knowledge of the object position and knowledge of each speaker location to create a rendering representing a near-ideal experience for the given speakers.

How does the DTS:X "spatial reformatter" work for existing 5.1 and 7.1 source material and how is it different than the Dolby Surround?

The Neural:X spatial reformatting engine is a completely new though is said to be based on Neo:X and Neural Surround.

Will implemention of Neural:X be limited to pre-predetermined layouts?

Some early models that support DTS:X will be firmware updates to units already in the field. These will no doubt subscribe to the predetermined layouts that are currently in the market. In the future as manufactures architect AVR systems around this new flexibility we will see support for unbound speaker layouts.

A DTS:X track is made of the DTS core element, DTS-HD MA residuals and DTS:X residuals. What are "DTS:X residuals"?

They include discrete objects, beds and metadata.

More FAQ Coming soon (for now, here is the DTS:X press release)

CALABASAS, Calif., April 9, 2015 /PRNewswire/ -- DTS, Inc. (Nasdaq: DTSI), a global leader in audio technology solutions, has unveiled further details about DTS:X, its open, next-generation, object-based, multi-dimensional audio technology. DTS:X replicates a real-world sound environment that transports the audience into a new dimension of sound immersion by delivering truly captivating entertainment experiences in the cinema and at home. The technology also provides numerous customization options for cinema and home theater owners.

Unlike existing surround sound systems, DTS:X is not tied to prescribed speaker configurations or a specific number of audio channels. DTS:X adapts to the viewing environment, allowing for a flexible speaker configuration that best fits the viewing space. DTS:X more accurately conveys the fluid movement of sound to create a richer entertainment soundscape than has previously been possible by moving sound objects to and through specific locations within - in front of, behind, above and beside the audience, precisely where the mixer placed them.

"DTS:X is built on the foundation of providing an open, adaptable solution for content creators, cinemas and homes to fulfill our goal of bringing immersive audio to as many people around the world as possible," said Jon Kirchner, chairman and CEO of DTS, Inc. "Until recently, sound in movie theaters and in our homes has been dictated by a standardized speaker layout. Through the use of object-based audio, DTS:X is able to scale immersive soundtrack presentations across a wide range of playback systems, from efficient to extravagant, while staying true to the content creator's vision. This approach delivers the most authentic three-dimensional audio experience ever, making the audience feel as if they are in the center of the action."

In 1993, DTS revolutionized cinema sound, delivering "Jurassic Park's" award-winning 5.1-channel soundtrack on CD-ROM, which was synchronized to the picture using a time code printed on the film. Twenty-two years later, DTS:X, the industry's newest audio solution, is no longer limited to channels or tied to a speaker layout and is now delivered as part of the Digital Cinema Package.

The foundation of DTS:X is MDA, DTS' license fee-free, open platform for creation of object-based immersive audio. MDA gives movie studios unprecedented control over the specific placement, movement and volume of sound objects. The platform also enables sound engineers to "mix once" for both immersive and conventional cinemas in a combined object- and channel-based audio format, allowing content to be easily distributed beyond the theater for streaming, broadcast, optical media and more.

"MDA is DTS' license fee-free contribution to the professional audio community for mixing and storage of immersive audio content," said Kirchner. "MDA fits perfectly within today's production workflow, and a combination of MDA and DTS:X provides a complete end-to-end workflow, from creation to exhibition."

The DTS:X licensing program in cinema will offer theater owners the opportunity to provide their audience the most compelling, immersive sound experience possible. This can be achieved for almost any room configuration by installing DTS:X-approved equipment and working with the recommended speaker installation guidelines.

To ensure quality and provide flexibility within the DTS:X program, DTS has partnered with industry-leading server, sound rendering and processing companies. GDC Technology, QSC and USL, have developed and made available DTS:X-ready components that process and render MDA files.
•GDC Technology - develops, manufactures and sells digital cinema servers and provides a comprehensive suite of digital cinema products, services and solutions for exhibitors and distributors
•QSC - designs and manufactures professional audio systems and solutions for professional installed, portable, production and cinema sound customers worldwide
•USL - is engaged in the design, manufacture, and sale of motion picture audio equipment and sound processors

GDC Technology is an initial partner integrating DTS:X into theaters.
•GDC Technology - boasts the largest installed base of digital cinema servers in the Asia-Pacific region, and the second largest, globally •GDC is the worldwide DTS:X certification agent with an exclusive in Asia
•GDC will make MDA firmware updates available to theater owners over to its existing installed server base of more than 40,000 servers starting in May 2015
•GDC will provide DTS:X installation and certification for approximately 350 screens throughout Asia beginning in May 2015

"GDC is committed to offering state-of-the-art technology to its customers. We chose DTS:X because we believe it will transform the movie theater experience for audiences around the world," said Dr. Man-Nang Chong, founder and CEO of GDC Technology. "Theater owners will appreciate the easy integration and flexible solutions that DTS:X offers as they upgrade their screens to this superior sound experience. Audiences win too. Because of the flexibility in speaker layout that DTS:X offers, immersive audio is now available to a larger number of theaters of all sizes than ever before."

DTS is presently working with several major studios and mixing stages in Los Angeles, Northern California and Canada that are evaluating DTS:X. DTS:X content announcements will be made by the studios when ready, in alignment with DTS.

Manufacturers representing nearly 90 percent of the home AVR and surround processor market will launch DTS:X-enabled products beginning in early Summer 2015, with additional manufacturer and model announcements to follow in the coming months. Confirmed AVR partners include:
•Denon - AVR-X7200W available now / DTS:X firmware upgrade later in 2015
•Integra - launching several models by Fall 2015
•Marantz - AV8802 available now / DTS:X firmware upgrade later in 2015
•Onkyo - launching several models by Fall 2015
•Pioneer - details to follow
•Steinway Lyngdorf - P200 Surround Sound Processor available Summer 2015 / DTS:X firmware upgrade in Fall 2015
•Theta Digital - Casablanca IVa available Summer 2015
•Trinnov Audio - Altitude32 available now / DTS:X firmware upgrade Summer 2015
•Yamaha - launching DTS:X ready models in Fall 2015

DTS:X solutions are also available for 2015 AV receiver silicon platforms representing the majority of the DSP platform market share, including Cirrus Logic, Analog Devices and Texas Instruments.

For home theater system owners, DTS:X provides personalization, flexibility and control for the most optimized listening experience possible. Key features include:

Backward Compatibility - DTS:X builds upon existing DTS-HD Master Audio to provide backward compatibility with existing DTS bitstreams and speaker layouts. In short, all features of DTS-HD Master Audio are supported and enable an immersive audio experience for older content.
•The DTS:X content is backward compatible with the DTS-HD decoder
•The DTS:X decoder supports DVD, Blu-ray Disc (BD) and streaming media file formats
•DTS:X can spatially reformat stereo, 5.1 or 7.1 content to take full advantage of all speakers in a surround system ◦Objects are never lost; if the object is embedded, it can be extracted and used in the rendered experience

Dialog Control - AVR owners will be able to control the volume of specific audio elements at home, such as increasing dialog volume to match their listening preferences.
•Dialog, as an object, can be lifted out from the background sounds when clarity and intelligibility are desired
•Content creators have the choice to implement this feature in their content mix

Flexible Speaker Layout - With flexible speaker layouts and remapping technology, DTS:X allows the placement of home theater speakers virtually anywhere. The freedom of object-based audio enables optimized playback on a multitude of speaker layouts, with any number of speakers. The DTS speaker remapping engine supports any speaker configuration within a hemispherical layout based around the listening position in the room.
•2015 DTS:X AVRs can support up to 11.2 speaker output channels
•Content created for a specific speaker layout can be remapped for playout through a different layout
•Enables remapping of outputs to custom or OEM-defined speaker layouts, and remapping legacy content to new output configurations
•Support for 32 speaker locations (subject to each manufacturer's product capabilities)
•Metadata-based spatial mapping renders the ideal 3D sound image to actual speaker layouts

Lossless - DTS is known for lossless, master audio quality with no compromise, delivering dynamic bit allocation. DTS:X supports lossless encoding for the highest audio quality possible. In situations where bitrate is of high concern, DTS:X can also operate in a high-quality lossy mode.
•Supports up to 96k for object mixes
•Still supports up to 192k for stereo and multi-channel mixes
•DTS:X is true to the audio master, delivers in the highest quality and preserves its fidelity

DTS Headphone:X
As part of DTS' strategy to support the entire ecosystem of sound, from cinema to home to mobile, consumers can also access an engaging audio experience over their mobile devices with DTS Headphone:X, which enhances any ordinary pair of headphones with fully immersive surround sound. With DTS technology, even the smallest screens will sound huge. Immerse yourself at and
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Last edited by marcuslaw; 11-19-2015 at 12:39 PM.
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post #2 of 5 Old 10-11-2016, 04:32 AM
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Originally Posted by marcuslaw View Post

How does Dolby Surround work with multi-channel sources?

Side and rear surround channels can be created from a 5.1 mix by simply specifying the correct output configuration that mimics the positions of the side surround and rear surround channels. For top speakers, Dolby Surround can be used to extract ambient or diffuse information from the input signals and steer it toward the top surround channels. Where two top speaker configurations, the diffuse signal from both the left and right channels as well as the diffuse signal from left and right surround channels can be combined. Where there are four top speakers, the diffuse signals can be combined or kept separate. If kept separate, then the top front receive only left and right ambience and the top rear only receive the left and right surround ambience.
Has Dolby published any information confirming that the commercial implementation of Dolby Surround combines the diffuse signals derived from each L/R pair (fronts, sides, rears), instead of keeping them separate? Because that is what seems to be happening on my Altitude32, and I cannot imagine that this is a limitation brought upon by Trinnov:

Originally Posted by maikeldepotter View Post
DSU upmixing of a legacy 7.1 track on a full Atmos lay-out creates two additional height channels that are matrixed accross the overhead arrays. So all the overhead speakers at one side get the exact same information. Same goes for the side and rear surrounds: all speakers at one side get the same signal. This basically means that while DSU addresses 17.1.10 speaker locations, it does not take advantage of the possibility to create discrete information for more than 9 main channels and a sub (see picture).

Attachment 1707697

By comparison: The Neural:X and AuroMatic up mixers generate respectively 11 and 13 discrete main channels plus sub, out of the same legacy 7.1 track.

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post #3 of 5 Old 10-11-2016, 06:13 AM
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Does Neural :X sound about the same as DSU?

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post #4 of 5 Old 05-26-2019, 06:00 PM
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I have a window 10 pc desktop. I have Dolby access app. After the last update my AVR X4100W Denon shows as a device, but I can no longer get it to show on the sound settings to set it as the default audio device
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post #5 of 5 Old 05-26-2019, 06:26 PM
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Originally Posted by asere View Post
Does Neural :X sound about the same as DSU?
That's a highly subjective question. YMMV.

IMHO, in some cases, yes, but in many cases, no.

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