From: Lang Elliott <>
>
> Interesting. When a mono source is "placed", what does the software actually
> do? I'm sure that it adjusts the differential loudness of the signals coming
> from different speakers, but does it also introduce delay and possibly do
> some spectral shaping to simulate head related transfer functions (HRTFs)? I
> imagine that it depends on the software that is being used.
Most such is just panning around a level circle, in fact just left to
right by adjusting sound level. But Soundhack has a binaural filter that
no only will place the sound in a 360 degree circle, but has up, down or
level. Either a fixed position, or a moving one. I've not played with it
much, so can't say what it can do. Has the advantage of being free, however.
http://www.soundhack.com/freeware.php
Here's what the manual says:
"This process allows you process a monaural soundfile (creating a stereo
file). The result is a signal at a simulated position around the head.
This is done by using a HRTF (head related transfer function) as a
filter, with a separate function for each position around the head.
To use the binaural filter, enter the desired position in the Angle text
box (in degrees) or click the appropriate radio button. This processing
module has filter data for 12 positions. If you enter an angle between 2
positions you will get a filter which is the mix of the 2 filters around
it. The Moving Angle box will allow you to do moving spatialization.
These HRTFs were obtained by Durand R. Begault, using methods described
in "3-D Sound for Virtual Reality and Multimedia" (Academic Press: ISBN
0-12-084735-3)."
The spectral dynamics filter in there is interesting too. The ability to
filter according to sound level. Selecting a specific part of the
dynamic range.
It also has a good sonogram display, though linear only.
Walt
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