[LAU] placement.

alex stone compose59 at gmail.com
Fri Jan 16 04:21:16 EST 2009


Fons, 2 follow ups.

Amb plugins are working now, with, somewhat predictably, user error as the
culprit.


Now to Jconv, and multiple short IRs.


I've done some crude experimenting and ask at this point, how do i determine
the format (i.e. short b-form ir or not) of a particular IR? Is there a
device or some sort of utility that i can use to do this?

The reason i ask is, i have a set of IR's for a hall, recorded 3 front
stage, left middle right, and 3 back stage, left middle right. I built a
jconv .conf file with these IRs, and the result was near 100% CPU, and a
vertiable flood of Xruns. (AMD 64 Dual Core X2 5600+, 64bit Ubstudio) I
understand from this, i've used 'full' IRs, and Jconv is attempting to
process them all at once.

So, I gather from what you've written, that there is either a mechanism for
creating short b-form IRs from a single IR wav, or i'll have to find a
specific IR that is recorded in such a way that i can use portions, or
sections of the IR, without taking such a performance hit, or there is a
mathematical means of extrapolating sections from a single ir, already
present in Jconv, and i'm not 'getting it', at this point.

I may be assuming all of the above incorrectly, of course, and presume it
may simply be a setup error here on my part, by default.

I would hope you glean from the above, that my enthusiasm for Jconv is not
only undimmed, but quite the contrary, has increased considerably with the
advent of this new source of knowledge and fresh journey of discovery. :)

Alex.


On Mon, Jan 5, 2009 at 1:52 PM, Fons Adriaensen <fons at kokkinizita.net>wrote:

> On Sun, Jan 04, 2009 at 05:16:09PM +0300, alex stone wrote:
>
> > Jorn, thanks for feedback. I've just tried one of Fon's amb plugs, and it
> > repeatedly crashed ardour,
> > further.
>
> They shouldn't, and here they don't...
>
> As to 'distance' placement, jconv is written to do the
> following efficiently:
>
> - Have a large number of short mono->b-form IRs, each
> one doing the early reflections for a given source
> location, and
>
> - A single long mono->b-form IR for the reverb tail.
>
> Then, for each source, you use *two* aux sends, the
> first to one of the short IRs, and the second to the
> reverb tail. Relative levels and a short delay on the
> first one will allow you control apparent distance,
> for a close source, the early reflection will have
> to come later and be weaker and vice versa.
>
> Creating such a config is a bit of work, it requires
> splitting up the full IR, ensuring everything remains
> aligned, etc. etc., but I have some. One of my projects
> (after the LAC probably) will be to automate this process.
>
> Ciao,
>
>
> --
> FA
>
> Laboratorio di Acustica ed Elettroacustica
> Parma, Italia
>
> O tu, che porte, correndo si ?
> E guerra e morte !
> _______________________________________________
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> Linux-audio-user at lists.linuxaudio.org
> http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
>
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