Re: New wavefield synthesis system -- holosonics?


Subject: Re: New wavefield synthesis system -- holosonics?
From: Scott Wilson (sdwilson@wesleyan.edu)
Date: Tue Jul 27 2004 - 06:36:50 EDT


Yes, that's more or less right. Of course this is nothing new in a way,
as IIRC there's been research going on about wavefield synthesis dating
back to the 1980's in Delft?

What's new is the integrated system. What I'm curious about is the
cost. At the moment it's seems prohibitively high, but as competing
systems become available, it seems likely to drop.

I also wonder about the possibility of implementing something like this
using custom software (I imagine the math is published) and
'relatively' inexpensive commercial hardware, eg a bunch of matched
speakers, a computer or two, and some MOTU 24 I/Os. Based on their
system this would be useless for realtime stuff, but it shouldn't be a
problem for pre-rendered things since we're just talking soundfiles.
With BEAST we've already been talking about using similar setups,
although not for wavefield synthesis, and not with that many speakers.

Scott

On 25 Jul 2004, at 22:59, Kevin Austin wrote:

> My uninformed guess is that it works on a principle something similar
> to holography (holosonics). It is likely 'size dependent', with
> different 'mixes' needed for different size spaces. As holography does
> not 'replicate' the object, but rather the wave patterns that would be
> created if the object were to be there, the creation of instantaneous
> sound pressure patterns (rather than the waves themselves) could be
> the objective.
>
> The example cited of a stone dropping into a pond may be a useful
> place to start. Drop the stone into a still pond, and take a picture
> of it. What exists is as wave pattern -- no velocity, simply
> displacement.
>
> As this surface is representative of the energy passing across it,
> this 'displacement' of a two-dimensional surface could be emulated by
> a surface that has small piston rods underneath it, and the rods would
> move up and down, creating the effect of the wave moving across the
> water (transverse wave motion if I recall). An animated explanation is
> at http://www.kettering.edu/~drussell/Demos/waves/wavemotion.html ...
> and this is taken from the excellent site:
> http://www.kettering.edu/~drussell/demos.html
>
> In air, the soundwave moves by longitudinal vibration. If the system
> (by using 400 small drivers) is able to emulate the kind of
> displacement which causes the brain to interpret the information
> correctly (as in a hologram), 'how' it is done is less important (to
> the listener). A form of 'holosonics'.
>
>
> Best
>
> Kevin
>
>
>
>
>
>
>
>> Judging from what was said, each sound must play on a separate
>> channel which can be localized independently. I wonder how many
>> channels it supports ... if you could have a sound object created in
>> a physical space and walk around it, and emulate distant sounds from
>> outside the room. Or create heirarchal structures, for example, not
>> just the position of the horse, but the position of each of the
>> horse's hooves, the horse's breath, etc, and then do that with maybe
>> say, a hundred horses moving across a battlefield..
>>
>> --st
>>
>> ----- Original Message -----
>> From: "Kevin Austin" <kevin.austin@videotron.ca>
>> To: <eamt@concordia.ca>
>> Sent: Sunday, July 25, 2004 2:29 PM
>> Subject: Fwd: New wavefield synthesis system
>>
>>
>>> Date: Sun, 25 Jul 2004 14:46:30 +0100
>>> From: Scott Wilson <sdwilson@wesleyan.edu>
>>> Subject: New wavefield synthesis system
>>>
>>>
>>> For the curious...
>>>
>>> http://www.iosono-sound.com/eng/index.html
>>>
>> http://news.com.com/MP3+creator+returns+with+3D+sound/2100-1026_3
>> -5280535.ht
>> ml
>>>
>>> Scott
>>>
>>>
>>> __________________________
>>>
>>> Scott Wilson
>>> Lecturer in Music
>>> Deputy Director of Postgraduate Studies
>> > Music Department
>> > University of Birmingham
>> >
>> > +44 (0)121 414 5767
>> >
>



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