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Topic: Dolby Virtual Speaker Technology (Read 4335 times) previous topic - next topic
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Dolby Virtual Speaker Technology

Read this white paper and THEN comment..  please, read it all (well you can skip some things if you want ) then write what you think, it would save lots of needless arguments.
The white paper can be downloaded as a PDF file.


At first, i was really pissed off reading all sorts of comments and news from news sites that copy from each other . Because none provided ANY "technical" info, so i automatically thought it's BS, got angry and ignored it for some time, and then i thought "DAMN IT i need some REAL info about this!" so i went to Dolby's site and found the REAL info. And i must say it seems good to me. I still have mixed thoughts about this, as i always do with things i can't test. Can't wait to listen to it.

(edited "technocal" , heh)

Dolby Virtual Speaker Technology

Reply #1 –
i just wonder: is this the newer stuff than 'dolby headphones', or is it the same thingy? (i listened to the 'dolby headphones' via powerdvd, but all i can say is -> DSP  )
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Dolby Virtual Speaker Technology

Reply #2 –
It's Virtual *Speaker* technology . Yes, it's the newer stuff.. Reading recommended.

Dolby Virtual Speaker Technology

Reply #3 –
it should be incompatible with headphones. i would think that everything short of the crosstalk stuff was developed for headphones, and then they made crosstalk cancellation so that they could use the same stuff in loud speakers.

the papers mention how most "virtual speaker" implementations don't consider the reflections off of the walls and what-not ("99% of the sound"!), but they don't mention how dolby does it. i don't get how the speakers or the chip could possibly know anything about the room you happen to stick the speakers in. isn't that what accounting for the reflections amounts to? do they assume a "normal room" as an approximation? also, i was under the impression that a lot of how you tell where a sound is coming from is due to phase differences (from dealing with earlobes, different sides of the head, etc.). i mean, i can tell when something is behind me pretty easily even if i'm in an empty field. i guess don't really see (1) why the reflections are so important and (2) how it's even possible to correct for (produce?)them in any accurate way.

Dolby Virtual Speaker Technology

Reply #4 –
Some are questions i was thinking about too..
Well i guess it's not about producing an accurate sound like it's supposed to be produced. It's -virtual- after all..
So many questions, so little nerves. (gotta listen to it)

Dolby Virtual Speaker Technology

Reply #5 –
The outer-ear reflections have a strong effect on how we can tell where a sound originates from. The 'spectral shape' is affected by how the ear attenuates or amplifies different frequencies, depending on how the sound travels around and through the ear. At least, that is how I understand it to be.

That said, we also rely on the volume, density, and duration of sound reflected off walls to tell us where we are in a room in relation to the source of the sound. Waves TrueVerb is a DirectX plugin that models this mathematically. Sonic Foundry's Acoustic Mirror does this by recording the sound an impulse when played in a room via a speaker (it records the original sound with the added reverb of the room). When you listen to music on speakers, you hear the size and characteristics of your listening room because of the reflected sound from the speakers, but you can also hear the size of the recording room from the recorded reflections.

We also locate sounds by the difference in time it takes the 'direct' sound to reach one ear compared to the other ear. This is what headphone crossfeed plugins model, although this doesn't need to be done with speakers unless you want to make the speaker appear to be somewhere where it isn't.

It sounds like this Dolby Virtual Speaker technology tries to turn speakers into a headphone-like environment by cancelling out the crossfeed (the effect I was talking about in the third paragraph in this post). Apparently it then does what the Dolby Virtual Headphone application does; it adds delayed and spectrally altered copies of the original sound, perhaps also spectrally altered the way Acoustic Mirror models certain environments using an impulse response.

I could be totally wrong about all of this. But it sounds like it would work somewhat better than the current surround emulators because it uses impulse responses to model the surround speakers, which will give a more natural and believable surround sound.

But the biggest problem is the one shimage mentioned. How does this technology take into account the listener's room reflections? The crossfeed cancellation helps initially, but if the listener has a 'live' room (lots of reflections due to windows and hard surfaces), I would imagine that all those special processing effects get mashed up in the listener's room reverb.

Does anyone feel like correcting any mistakes I may have made in this post?

Dolby Virtual Speaker Technology

Reply #6 –
Quote
It's Virtual *Speaker* technology . Yes, it's the newer stuff.. Reading recommended.

I feel to agree with SW, don't think it's new technology
this sounds me...

Aureal

Vortex2 chip does ~ same thing, I think.
Years ago Aureal has started its activity by researching and dev. 3D audio manipulation for NASA simulators, further they have entered in sound cards market with great success (initially).
Now Aureal guys (the company itself closed and was bought by Creative ) are working in Nvidia corp., they have built also Nforce and Xbox audio.

Sensaura standard as old Aureal3D uses the same concept, but also with rear speakers.
"Taking a jazz approach and concentrating on live playing, I wanted to use several different rhythm sections and vintage instruments and amps to create a timeless sound that's geared more around musicality and vibe than sonic perfection. The key was to write with specific rhythm sections in mind, yet leave open spaces for soloing." Lee Ritenour

Dolby Virtual Speaker Technology

Reply #7 –
from http://dolby.com/press/ce_pr_0210_VirtualSpkr.html

Quote
The algorithm at the heart of Dolby Virtual Speaker is based on advanced psychoacoustic parameters that include an understanding of sound from both a technical and a human, experiential perspective. In a typical listening environment, the sound from a speaker is reflected within the room before reaching a listener's ears, arriving at different times at each ear, and at different amplitudes and equalization from the direct sound. The brain's interpretation of these separate audio elements supplied to the right and left ears allows the person to identify the direction and distance of the sound's source.

Dolby Virtual Speaker technology joins several other significant Dolby technologies that have improved people's everyday entertainment lives, notably Dolby Digital-the world's most popular digital surround sound format, experienced in movie theatres, DVDs, digital television, and games-and Dolby Headphone technology, a value-added solution for providing dramatic surround sound effects from any conventional set of headphones.


and its my 100th post...
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