Re: [LAU] placement.

Fons Adriaensen wrote:
> On Tue, Jan 20, 2009 at 06:34:27PM +0100, Jörn Nettingsmeier wrote:
>
>> to clarify things, there are no "short" or "long" IRs. what fons means
>> is: the early reflections are the most characteristic aspect of a room,
>> and they affect localisation the most.
>
> I don't think I can really agree with the first part of this
> statement, but the second part is certainly true.

goes to show to always craft your words very, very carefully if math
guys are near....
what i meant is: if you get a standard IR file, it will always include
both the early reflections and the reverb tail. i had a feeling that
alex was being led on the wrong track by these terms.

there are no mythical "long" and "short" IR files.
only complete (with tail) and incomplete ones (ideally cut off at some
meaningful point, such as before the onset of the purely diffuse tail -
which of course isn't precisely defined...)

>> so instead you use one reverb IR instead. it can be short (tail
>> truncated) to save CPU, because the tail is decorrelated (blurred) and
>> does not provide localisation cues, hence it would be wasteful to render
>> it in b-format.
>
> But I wouldn't say it is wasteful to render the reverb tail
> in B-format, on the contrary, doing that makes it very realistic.

true if the final product is going to be surround. for something that
will end up as plain old stereo, i'd maintain that it doesn't make much
of a difference. but then again, for POS, the whole exercise is probably
overkill.

i agree that b-format reverb tails are nice. what i should have said is:
reverb tails do not provide localisation cues and will not warrant
separate handling for each source....

another problem that might come up is to obtain anechoic instrument
samples. i find that a mixture of small-room early reflections created
by the room used for sampling and the large target room IR screws up the
illusion quite effectively...

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Received on Wed Jan 21 04:15:02 2009