Hi David...
As you are a knowledgeable expert on this stuff :-) , I would like to
take the discussion of this article/interview to a higher level...
The interesting part of the interview is on the 2nd page:
http://www.hometheater.com/content/tech-spotlight-page-2
But with the full evolution to MDA, the creator can tell us, say, we
want objects panned not just around a twodimensional plane, around the
edges like you can do with traditional surround, but also around
interior points, immersive points. Even with 7.1 today, the sound is
still in a two-dimensional plane, and it still clings to the speakers
and to the walls—you don’t get the feeling that you’re immersed in the
soundfield.
So why not use what we know about the hearing system to create this
perception of three-dimensional space and emergence without a lot of
boxes hanging around the room? That defines the whole theory of
psychoacoustics: Let’s use the hearing system directly, rather than
indirectly with speakers all over the place.
Now, it turns out that one of the techniques for projecting sound into
space based on the auditory system is something called HRTF, or
head-related transfer functions, where the frequency or spectral
characteristics of a broadband audio signal, like speech or music,
will vary depending on the angle relative to the ear canal. And that’s
because of the structure of the head and the outer ear, and the
shoulders—everything. And by understanding how that changes, we can
take advantage of HRTF to create sounds in three-dimensional space,
from a perception standpoint, that aren’t actually coming from speakers.
Which means that they are probably using HRTF techniques. Because HRTF
is an individual parameter, they would have to use some form of
"standard" HRTF, as long as they don't perform individual measurements.
For me, the interviewer didn't ask the right questions. To be fair, the
interviewer can't have sufficient scientific/technical background if he
did not read every single contribution on the sursound list during many
laborious years... :-D
The next thing that you heard with CC3D was another psychoacoustic
phenomenon that we kind of discovered last year about what sounds do
when they come closer versus moving farther away. And we found that we
were able to simulate something that normally can’t be done with
traditional surround sound, which is proximity.
And again, that’s not just amplitude. So we’re taking advantage of
what we learned there to create this feeling that things are being
projected into space in the D axis, the depth axis.
This < might > be something new, and indeed difficult to obtain with 5.1
or (classical) Ambisonics. (If at all.)
So, when you have this two-speaker concept, this
minimal-number-of-speakers concept, you can create a much more
immersive soundfield because it’s matching playback to the human
ear-brain system, to the perception system, in a much better way than
you can when you’re just simulating surround by putting speakers
around the room.
But as 2 speakers are too limited if you want to hear anything real (or
at least "non-gimmick") from behind...
So what we’re working on now is essentially a multichannel or 5.1
version of the twochannel system that you heard. You can have speakers
back there, as long as you treat all the speakers with the same kind
of technology to maintain this immersion.
However, X-talk cancelling techniques would require close speakers. Even
if you consider that you have three frontspeakers in 5.1 (C, L, R), I
would think that C doesn't really matter a lot, and you still have to
consider 60º X-talk cancellation between L and R.
Or is this a different 5.1 system, say Ambiophonics with 2 or 3
surround speakers?
What I heard that day at SRS was a witch’s brew of breakthrough audio
technologies, a combination of new psychoacoustic depth-rendering
techniques applied through the filter of a game-changing approach to
mixing movie soundtracks that SRS calls Multi-dimensional Audio, or
MDA. Together, they form the basis of CircleCinema 3D, a feature that
will begin appearing in flat-panel HDTVs and soundbars from SRS
licensees in 2012, and perhaps later, in A/V receivers.
If we speak about flat-panel HDTVs, this should be an X-talk elimination
based system.
You can't offer receivers if there is not an agreed surround standard
yet(supposedly based on audio objects).
The system might be a kind of combination of Mpeg-4 (audio objects) ,
soundfield techniques and X-talk elimination.
But the coding of depth cues seems to be something new, and if this
works, it is really impressing.
Now, I just wanted to dispute the claim that SRS isn't offering anything
new at all. Probably they do, at least they are trying to apply some
combination of existing technologies into the maketplace.
Best regards
Stefan
P.S.: The next surround system has to be independent of speaker
configurations, and to include the 3D/"sphere" aspect. If you can
reproduce distance cues, even better.
Dave Malham wrote:
Hi Jörn and Bearcat
On 16/07/2011 06:56, Jörn Nettingsmeier wrote:
On 07/16/2011 01:32 AM, "Bearcat M. Şandor" wrote:
I found that review/interview of the 2 channel surround sound i was
referring to earlier:
http://www.hometheater.com/content/tech-spotlight-srs-future-surround
The first copy i saw didn't have the 2nd page. In it it's explained
that
you'd need speakers behind you to hear things behind you.
Hmm, reading through this, it seems that basically they've discovered
MPEG4 Spatial Audio Object Coding :-)
They speak of proximity, of things moving closer and further away from
your face. Can ambisonics do that as well?
classical ambisonics doesn't really do that. on good recordings, you
will get a very nice sense of distance, but that is due to distance
cues which are more or less independent of ambisonics (any good
recording method can do it).
what you definitely won't get (with any order less than "ridiculously
high") are sources closer than the ring of speakers.
Whilst I agree that you can't generally get stationary audio objects
closer than the radius of the speakers on low order systems
(currently, only high order Ambisonic systems, WFS or crosstalk
cancelled binaural systems can do that - oh, and the various
ultrasound based speakers), you can get reasonably quickly moving
objects to appear to pass close by, especially if the acoustic of the
playback space is dead relative to the reproduced space, provided you
give enough cues (particularly early reflection patterns and proximity
effect) in the soundscape to override the conflicting playback space
cues. Whilst this also occurs with any decent replay methodology, it
is easier with Ambisonics because (I suspect) of the fact that there
is always more than one speaker producing sound, so the local space
cues conflict not just with the soundscape cues, but also each other,
weakening the perceptual effects of the local cues.
Dave
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