Which amount of canals needs perfect rendition?

[syntheticwave]

I say ONE for a single source.

Each source itself it’s a mono source. Why we should broadcast a mono source signal in 7.1 or more canals? We want by that way to restore the spatial behavior of the sonic field. But what for a ineffective way, to transmit the same signal more as one times in that matter, only because amplitude and phase differs a little. Let my describe a much better way:

The spatial sound field in the recording room constitutes from the direct wave, radiated by the sound source. That wave front becomes reflected by all surfaces in the recording room. We can imagine those reflections by mirror source model. Each reflecting surface creates such mirror source behind. Its spatial position is dependent from the listener position, its signal become modified by the surface reflection factors.

The spatial distribution of those mirror sources are situated all around the listener, the reflections arrive by the listener from all directions. That’s decidedly the spatial impression. Especially the relationships of direct wave and early strong reflections are vital for the perception.

Reducing those spatial distribution of the mirror sources upon the horizontal level, moreover upon a few single canals inevitably caused a significantly loss of spatial impression! Hence it makes much more sense, to transmit only the pure mono signal of the source. If stored the reflection purposes of the recording room by the rendition side, by principle of wave field synthesis the spatial sound filed become synthetisized much more accurate from that information’s.
The procedure is described by easily understandable animations by my website http://www.syntheticwave.de/Wavefieldsynthesis.htm or also shortly by Wikipedia.

Should that procedure in principle been able to create a virtual copy of the rendition room sound field in future? And what’s by your opinion the chance for the home market?


Kind Regards Helmut

 

[gullfo]

interesting, what type of self-adjustments would such a system have for varying room acoustics - dead to very live?

 

[syntheticwave]

Hi Gulfo,

before I am reply let my insert a relaunch of my text, it was noticin it was very bad English. Better attempt, I hope:


Mono makes the best reproduction!
________________________________________

That seems a little bit crazy, but each source themselves is a mono source. It makes no sense transmitting a mono source signal in 7.1 or more channels. We want to restore the spatial behavior of the sonic field in that matter. But what ineffective way, transmitting the same signal more as one times, only because amplitude and phase differs a little. Let my describe a more useful way:

The spatial sound field in the recording room becomes initiated from direct wave, radiated by the sound source. That wave front will reflected by all surfaces in the recording room. We can imagine those reflections by mirror source model. Behind each reflecting surface such mirror sources occur. Its spatial position dependent from listener position, its signal become modified by the surface reflection factors.

Those mirror sources situated all around the listener, the reflections arrive by the listener from all directions. That’s decidedly the spatial impression. Reducing those spatial distribution of the mirror sources upon the horizontal level, moreover upon a few single channels inevitably caused a significantly loss of spatial impression!

More meaningful is the way, transmitting only the pure mono signal of the source in addition to the reflection properties of the recording room. By principle of wave field synthesis the spatial sound filed become synthesizing much more accurate from that information’s. The procedure is described by Wikipedia or in drolly English, but with easily understandable animations by my website www.syntheticwave.de . Such wfs- rendition systems installed in some cinemas currently. I was able to listen sometimes, the spatial impression incomparably more precise as conventionally reproduction. The virtually source has the ability to whisper directly into your ear, in principle is possible go around the virtually source hence.


Now your Question:

interesting, what type of self-adjustments would such a system have for varying room acoustics - dead to very live?

I have a patented approach for including the rendition room properies into the synthesis. By that way the rendition room properies become strored while the instalation of the system. See that animation:

http://www.syntheticwave.de/pictures/principe.swf

The wfs speaker field work behind the screen wall. Caused by the high directive effect become possible, retarding selected wavefronts. The rendition room properties known for the system. Thus equalizing of the differencies regarding the recording room is not only possible in frequencie domain, but in time domain. In the depiction the living room ceiling reflection arrive at the same time behind direct wave by the listener as in the recording room. That caused the same ceiling high impression.
Tohose principle for all reflections is shown here:

http://www.syntheticwave.de/pictures/WFS_transformation_principle.swf

Kind regards Helmut

 

[syntheticwave]

More easyly description

Hi,
the topic is a little complicared, let my try a more simply description:

Imagine you are situated in an opera house, best place, great tenor sings. Suddenly unexpected some bricklayers come in, build up a little housing around you. You are angrily, 56$ for the ticket and now you can hear nothing!

But help is coming. One of the masons made holes into all walls, 10 cm in diameter, each on the other. Super, you hear Caruso as good as without the house. But now the electricians coming, sticking each hole by a loudspeaker. The sound is blocked again, but then, suddenly you hear likely the holes would be open. The electricians have supplied each speaker by a small amplifier and a microphone just on the outside of each hole. Nothing is changed, speakers and microphones working well today.

The problem is only; you need one discrete channel for each micro, if you want to build the speakers into your living room walls. The second, mostly bigger problem is your wife, if you want to load all walls around in your living room by loudspeakers.

The side does nothing else as describing a solution for those two problems. It describes a way for build up all different signals for the direct wave from a dry recorded mono track for each singer. The same signal is able for generate the first strong reflections in the recording room, which hit the listener from different directions. That's the core of each acoustic, by conventionally loudspeaker reproduction we are far away from the goal, to be able to reproducing this spatial distribution correctly. The reverberation tail then becomes created from the impulse response, that's common practice in all studios today. The impulse response becomes suppressed for the early reflection time, so that the first reflections don't produce again. The reverberation is coming from all directions by such approach, likely in the opera house.

By including of the reflecting playback room walls, as it is known from the directed radiation used in the sound projectors, you can resign the loudspeakers all around, only those behind the picture screen remain. Your wife shouldn't' be able for discover that, the signal of each single speaker (holes) are hardly louder as the sound by the listener place. But the speaker field isn't producing virtually loudspeakers, as doing in the sound projectors. The speaker field simulates the source itself. Nothing else is described on the website.


Kind regards Helmut
www.syntheticwave.de