Re: Linux binaural analysis

[Catherine Emily Carr <cc117@xxxxxxxxxxxxx>]

Eric Mousset <mousset@SEDAL.USYD.EDU.AU> wrote:

>The department I am working for is considering purchasing some
>equipment for research purposes in binaural hearing (HRTF-based sound
>source localisation, amongst others).
>The computer on which we are intending to run the (real-time) binaural
>analyses is a PC running LINUX.
>
>1) Part of the question is general and applies to anyone interested
>   in real-time sound source localisation with a pair of mics as input:

>   There are apparently two main options for the acquisition of the
>   acoustic signals: a sound-card vs an A/D convertor. How do they
compare?
>
>2) Linux-oriented question: Do most cards have drivers for Linux?
>
>
>Many thanks in advance.
>
>
>Eric.

We at Mark Konishi's lab, Caltech, do exactly what you want to do, it
seems.  We use have computers running Linux 2.x and SunOS 4.1.x to do
both behavioral studies and neurophysiology concerning sound
localization in owls.   We have done experiments with HRTF-based sound
source localization, so what you seem to want to do can indeed be done.

For neurophysiology, we use a custom written piece of software that runs

under X-windows, and for the behavioral stuff we use Matlab with some
extensions that we wrote to control the hardware.

We use a data acquisition system from Tucker Davis Technologies, which
consists of an ISA card connected to rack-mounted A/D and D/A conveters
via fiber optic cables, in addition to filters, programmable
attenuators, and some other equipment.  This stuff works pretty well
under Linux, with a few little glitches every few weeks, but that's
it.

I had thought as you did to use a sound card for my data acquisition
device when I started four years ago.  This was a royal pain in the
butt.
At that time, there were primitive drivers for a very few data
acquisition
cards.  The Linux sound drivers in the 1.3.x kernels for the card I
was using, the Gravis Ultrasound MAX, were not satisfactory, and after
about six months of struggling with it, I admitted defeat, and we
started
looking for another system, eventually deciding on the Tucker Davis
stuff.   It would probably be easier to make the sound card work now, in

the 2.2.x kernels.

Many data acquisition cards have drivers (at varying levels of
functionality)
under Linux now: see the Comedi project <http://stm.lbl.gov/comedi/>

If anyone has any other questions, they can e-mail me, since I'm not on
this list.

Chris

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Posted by:

Catherine Carr
Dept Biology
Univ Maryland
College Park
MD 20742-4415

301-405-2085 (office)
301-405-6915 (lab)

http://www.glue.umd.edu/~carr/