[Sursound] Converting 16 mic array recording to B format

2015-05-11 Thread Curtis Alcock
Hi All

I am wondering how I go about converting a recording made with a 16 microphone 
array into B format?

I have downloaded the 16 channel recordings of noise from the DEMAND: Diverse 
Environment Multichannel Acoustic Noise Database and would like to play them 
back through an ambisonics rig.

The recordings were made using a "microphone array of 16 microphones arranged 
in 4 staggered rows, spaced such there is a 5 cm distance form each microphone 
to its immediate neighbors. The array is in a plane which in all recordings is 
parallel to the ground."

The authors include a "MATLAB script which creates a 16 x 2 MATLAB array with 
the xy coordinates (in meters) of each channel microphone relative to the 
microphone of channel 1."

I don't have MATLAB, but I'm assuming that somehow I can still use the 
positional information from the array, but I confess I don't know what the 
process is or what software is required.

Any guidance would be most appreciated.

The website for DEMAND is: http://parole.loria.fr/DEMAND/

With kind regards

Curtis Alcock
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Re: [Sursound] Converting 16 mic array recording to B format

2015-05-11 Thread Michael Chapman
> Hi All
>
> I am wondering how I go about converting a recording made with a 16
> microphone array into B format?
>
> I have downloaded the 16 channel recordings of noise from the DEMAND:
> Diverse Environment Multichannel Acoustic Noise Database and would like to
> play them back through an ambisonics rig.
>
> The recordings were made using a "microphone array of 16 microphones
> arranged in 4 staggered rows, spaced such there is a 5 cm distance form
> each microphone to its immediate neighbors. The array is in a plane which
> in all recordings is parallel to the ground."
>
> The authors include a "MATLAB script which creates a 16 x 2 MATLAB array
> with the xy coordinates (in meters) of each channel microphone relative to
> the microphone of channel 1."
>
Weird ...
... must admit to _not_ having followed the link ... so perhaps mea culpa,
... but

A MATLAB script might be a courtesy to those that use MATLAB, but we are
only talking about 30 numbers ... akin to "see the attached Word(TM) file
for my postal address" ;-)>

All the mics are in a horizontal plane(?) and the sounds presumably(??)
mostly off to the sides.
So you can only (at best) extract pantophony (2-D ambisonics).

To record that you would only have needed 3 (or 4) mics
_as_close_together_as_possible_.

To extract something from (some of) the sixteen:
-I'm not optimistic
-you'd need to know about polar patterns, directions, whether they shield
each other, ...

If you don't get a better reply I'm happy to visit the link and be more
serious ... but on this list there is usually someone who's already (with
success, or not) 'been down that route'.

Michael

> I don't have MATLAB, but I'm assuming that somehow I can still use the
> positional information from the array, but I confess I don't know what the
> process is or what software is required.
>
> Any guidance would be most appreciated.
>
> The website for DEMAND is: http://parole.loria.fr/DEMAND/
>
> With kind regards
>
> Curtis Alcock
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> Sursound mailing list
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> edit account or options, view archives and so on.
>

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[Sursound] Survey to share among students and researchers - food and soundscapes

2015-05-11 Thread Felipe RC (Sonic.Taste)
Dear colleagues and friends,

I am starting to prepare a new experiment that involves associating food, 
soundscapes and music. 
As a preliminary study, I need to gather juicy data by means of an on-line 
survey.
Can you please share it among your students, colleagues and friends?

Please find enclosed the link to access it:

http://tinyurl.com/soundandfood <http://tinyurl.com/soundandfood>

It takes less than 10 minutes to answer… Have fun! 
Don’t forget to use headphones or, at least, a good pair of speakers.

Thanks in advance.
All the best,



Felipe
--


Felipe Reinoso Carvalho
Twitter @sonictaste
f.so...@gmail.com <mailto:f.so...@gmail.com>http://sonictaste.flavors.me 
<http://eideias.flavors.me/>


+ 32 (0) 489353218




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Re: [Sursound] Converting 16 mic array recording to B format

2015-05-11 Thread Tim Collins
I think you probably do have a good chance of being able to do this using 
conventional beamforming techniques but with the following provisos:

- Given the mic spacing, the beams will only be accurate at frequencies below 
about 2kHz
- You will need to assume that the mics are omnidirectional and do not shadow 
each other
- Some height information could be derived but not very accurately and there 
will be an upwards-downwards ambiguity

For an idea of the processing required, you may find this paper useful:
https://www.researchgate.net/publication/44035458_Sound_Field_Recording_by_Measuring_Gradients

Best wishes
Tim


-Original Message-
> Hi All
>
> I am wondering how I go about converting a recording made with a 16 
> microphone array into B format?
>
> I have downloaded the 16 channel recordings of noise from the DEMAND:
> Diverse Environment Multichannel Acoustic Noise Database and would 
> like to play them back through an ambisonics rig.
>
> The recordings were made using a "microphone array of 16 microphones 
> arranged in 4 staggered rows, spaced such there is a 5 cm distance 
> form each microphone to its immediate neighbors. The array is in a 
> plane which in all recordings is parallel to the ground."
>
> The authors include a "MATLAB script which creates a 16 x 2 MATLAB 
> array with the xy coordinates (in meters) of each channel microphone 
> relative to the microphone of channel 1."
>
Weird ...
... must admit to _not_ having followed the link ... so perhaps mea culpa, ... 
but

A MATLAB script might be a courtesy to those that use MATLAB, but we are only 
talking about 30 numbers ... akin to "see the attached Word(TM) file for my 
postal address" ;-)>

All the mics are in a horizontal plane(?) and the sounds presumably(??) mostly 
off to the sides.
So you can only (at best) extract pantophony (2-D ambisonics).

To record that you would only have needed 3 (or 4) mics 
_as_close_together_as_possible_.

To extract something from (some of) the sixteen:
-I'm not optimistic
-you'd need to know about polar patterns, directions, whether they shield each 
other, ...

If you don't get a better reply I'm happy to visit the link and be more serious 
... but on this list there is usually someone who's already (with success, or 
not) 'been down that route'.

Michael

> I don't have MATLAB, but I'm assuming that somehow I can still use the 
> positional information from the array, but I confess I don't know what 
> the process is or what software is required.
>
> Any guidance would be most appreciated.
>
> The website for DEMAND is: http://parole.loria.fr/DEMAND/
>
> With kind regards
>
> Curtis Alcock
> ___
> Sursound mailing list
> Sursound@music.vt.edu
> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe 
> here, edit account or options, view archives and so on.
>


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