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Trying to cancel out the natural HRTF...

Date2017-02-17 13:57
FromSteffenE
SubjectTrying to cancel out the natural HRTF...
Dear list,

I'm looking for a way to get the HRTF from the HRTF opcodes. It says here
[1] where to find the ‘spectral’ HRTF data - but I am unsure what the data
file describes and in which format. My goal is, I believe, a form of
deconvolution (dividing by the frequency response of the HRTF at a certain
angle) in order to equalize an HRTF-filtered signal to cancel out the
natural HRTF that will be created due to the angle between the listener and
the loudspeaker (as described in this paper [2]. If the data cannot be
obtained from the file directly, is there a way to sample it from the opcode
(take an Impulse Response)? What would be the opcodes to best use for this
purpose? Many thanks for any help in advance!

[1] http://www.csounds.com/journal/issue9/newHRTFOpcodes.html
[2]
https://www.researchgate.net/publication/233658043_Elevation_in_Wave-Field_Synthesis_Using_HRTF_Cues



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Date2017-02-17 14:39
From"Jeanette C."
SubjectRe: Trying to cancel out the natural HRTF...
Feb 17 2017, SteffenE has written:

> Dear list,
>
> I'm looking for a way to get the HRTF from the HRTF opcodes. It says here
> [1] where to find the ‘spectral’ HRTF data - but I am unsure what the data
> file describes and in which format.
As far as I understand, the contents is a collection of impulse
responses, measured at many points around the head used to generate the
model. Format: no idea.
> My goal is, I believe, a form of
> deconvolution (dividing by the frequency response of the HRTF at a certain
> angle) in order to equalize an HRTF-filtered signal to cancel out the
> natural HRTF that will be created due to the angle between the listener and
> the loudspeaker (as described in this paper [2].
If this has any chance of working, you can only undo the HRTF, if you're
signal was generated by the same HRTF model. So that means by csound
itself or by another software using exactly the same data. But even then
I'm unsure if it could work. After processing a signal by an HRTF
opcode, many different impulse responses will be applied, depending on
the signals movements. If it's a static HRTF, i.e. the signal is left
static at one point in space, you could succeed, but even then you'd
have to work out the correct angles.

I'm no expert on these matters, by I know a little about convolution.
Maybe there are some clever tricks I don't know about. So take this with
a pinch of salt.

Best wishes,

Jeanette
...

--------
When you need someone, you just turn around and I will be there <3

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Date2017-02-17 21:54
From"Dr. Richard Boulanger"
SubjectRe: Trying to cancel out the natural HRTF...
Wondering too...

Do we have a comprehensive set of Deconvolution Opcodes (yet) ?

Like the work of Paris Smaragdis
- maybe we can get him to turn his software into a nice set of opcodes for us.

Dr.B.

On Fri, Feb 17, 2017 at 9:39 AM, Jeanette C. <julien@mail.upb.de> wrote:
Feb 17 2017, SteffenE has written:

Dear list,

I'm looking for a way to get the HRTF from the HRTF opcodes. It says here
[1] where to find the ‘spectral’ HRTF data - but I am unsure what the data
file describes and in which format.
As far as I understand, the contents is a collection of impulse
responses, measured at many points around the head used to generate the
model. Format: no idea.
My goal is, I believe, a form of
deconvolution (dividing by the frequency response of the HRTF at a certain
angle) in order to equalize an HRTF-filtered signal to cancel out the
natural HRTF that will be created due to the angle between the listener and
the loudspeaker (as described in this paper [2].
If this has any chance of working, you can only undo the HRTF, if you're
signal was generated by the same HRTF model. So that means by csound
itself or by another software using exactly the same data. But even then
I'm unsure if it could work. After processing a signal by an HRTF
opcode, many different impulse responses will be applied, depending on
the signals movements. If it's a static HRTF, i.e. the signal is left
static at one point in space, you could succeed, but even then you'd
have to work out the correct angles.

I'm no expert on these matters, by I know a little about convolution.
Maybe there are some clever tricks I don't know about. So take this with
a pinch of salt.

Best wishes,

Jeanette
...

--------
When you need someone, you just turn around and I will be there <3


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--
_____________________________________________
Dr. Richard Boulanger
Professor of Electronic Production and Design
Professional Writing and Music Technology Division
Berklee College of Music
______________________________________________
President of Boulanger Labs - http://boulangerlabs.com
Author & Editor of The Csound Book - http://mitpress.mit.edu/books/csound-book
Author & Editor of The Audio Programming Book - http://mitpress.mit.edu/books/audio-programming-book
______________________________________________
about: http://www.boulangerlabs.com/about/richardboulanger/
about: http://www.csounds.com/community/developers/dr-richard-boulanger/
music: http://www.csounds.com/community/developers/dr-richard-boulanger/dr-richard-boulanger-music/

______________________________________________
email: rboulanger@berklee.edu
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