Re: spatialisation using headphones

[Holger Prante <Prante@xxxxxxxxxxx>]

Hamish,

i was wondering for what reason you are going to use headphones in your
experiment. You would have to fix the subject's head during the test which
would mean to prepare a more sophisticated set-up. If you won't fix the head
the subject could turn it during presentation of the stimulus. This would
lead to a spatial divergence between the auditory and the visual event.
Moreover, due the the mentioned rather vaguely matched HRTF you would have
your auditory event always blurred a bit (broad band signal assumed).
However, everything depends on your test hypothesis.

i would suggest using loudspeaker reproduction and using the well-known
level and time differences between the speaker pair in order to adjust your
signal spatially. This way you don't have to worry that much about the
correct HRTF - you will always get the right one ;-)

Best regards
Holger

------------------------
Dr. Holger U. Prante
Project Manager



----- Original Message -----
 > Hello list!
>
> I'm a PhD student at the Brain Sciences Institute in Melbourne, about to
> embark on my first experiment looking at cross-modal attention affects on
> event-related brain potentials.  I'm planning on using simulated "spatial"
> stimuli in one of my tasks.  I have some flashing lights located on the
> left, right and center in front of a subject.  There are some beeps that
I'd
> like to play thrpough headphones AS IF they were coming from the location
of
> the flashing lights.
>
> They don't have to be exactly localised at the location of the lights, but
I
> would like them to be vaugely from the same area.  What I'm looking for is
a
> way of "spatialising" my (already made up) sound stimuli.  I'm aware that
> the HRTF for each person is different, but am think that perhaps i could
use
> a small set of typical HRTF's that would cover "large-headed",
> "small-headed" etc people.
>
> What I was wondering was
>
> 1) is this a good idea
> 2) where should i start looking for ways of actually implementing this?
>
> I have a passing familiarity with MatLab etc
>
>
> many thanks for any pointers in the right direction!
>
> -hamish-