Hi everyone,

On this page you have some information regarding the capsules (and frequency 
response), DSP, and the currently available software applications  (ZYLIA 
Studio, Studio Pro and ambisonics converter).

http://www.zylia.co/white-paper.html <http://www.zylia.co/white-paper.html>


______
Eduardo



> On Aug 17, 2018, at 5:14 AM, umashankar manthravadi <umasha...@hotmail.com> 
> wrote:
> 
> zyla is made of mems. We are now getting low noise and high sensitivity mems, 
> but they are still omni.
> 
> Omni mounted on the surface of a sphere has some directional characteristics. 
> Later today I am going to measure a single mems loaded with a 16 mm square 
> horn (mouth flush on a 40 mm sphere) to see what kind of directivity pattern 
> I will get.
> 
> umashankar
> ________________________________
> From: Sursound <sursound-boun...@music.vt.edu 
> <mailto:sursound-boun...@music.vt.edu>> on behalf of Fernando Lopez-Lezcano 
> <na...@ccrma.stanford.edu <mailto:na...@ccrma.stanford.edu>>
> Sent: Friday, August 17, 2018 12:05 AM
> To: Surround Sound discussion group; Len Moskowitz
> Cc: Justin Bennett
> Subject: Re: [Sursound] Looking for mic advice (Zylia)
> 
> On 08/16/2018 10:22 AM, Bo-Erik Sandholm wrote:
>> I agree with Len, we have not seen any technical spec of self noise level
>> of the MEMS (clusters?)  that are used in Zylia.
>> 
>> Only text saying that in normal musical recording situations self noise is
>> not disturbing :-).
> 
> :-)
> 
>> I have a personal theory that self noise of physical elements in an
>> ambisonic mic array is not directly additive.
>> The basis for my theory is that as we convert to B-format the noise from
>> all the physical elements are distributed over a spherical surface,
>> and the noise level for a virtual microphone in decoding do not have the
>> full sum of the added microphone noise levels.
>> Only coherent noise within the take up volume of the virtual microphone is
>> relevant in that directional microphones response.
> 
> I think the noise we are talking about is that of the difference
> microphones. In an open array built with cardioids that would be for
> order 2 or higher, in a rigid sphere array with omnidirectional capsules
> that would be for order 1 or higher.
> 
> Those components drop in level at low frequencies at a rate of n x
> 6dB/octave (starting at high frequencies). For the second order
> components of a microphone made of cardioids n = 1 (6dB/oct), add
> 6dB/oct per order increase for higher orders.
> 
> As the component drops in amplitude towards the low frequencies you need
> a filter that compensates for the drop, and of course it amplifies the
> sef-noise of the capsules as well. At some point you have to give up or
> the noise becomes a problem (where exactly depends on the self-noise of
> the capsules and what kind of materials you are recording).
> 
> In the second order microphones I'm building for the SpHEAR project I
> can use the second order components down to about 400-500Hz ("unity
> gain" for them is at around 9KHz). Even then the noise is objectionable
> (but not necessarily "disturbing" :-) for recordings that have wide
> dynamic range (my encoder uses an expander on those components to try to
> minimize that effect). You can definitely hear the noise if there is a
> silence in the recording. Of course it disappears if you mute the second
> order components :-)
> 
> A third order microphone (made of cardioids - I don't think there is
> one) would be worse, the drop would be 12dB/oct for the third order
> components. So you would have to limit the low end of the frequency
> response at a higher frequency.
> 
> AFAIK nobody specifies the noise specs for _those_ components in an
> Ambisonics microphone. In a first order microphone made of cardioids
> that is not a problem, as is the case for the first order components of
> a second order microphone made of cardioids.
> 
> (as a reference, the open source octofile software released for the
> OctoMic shows that their calibration has three choices for the low
> frequency cut off for the second order components, 500Hz, 900Hz and
> 1.5KHz).
> 
> -- Fernando
> 
> _______________________________________________
> Sursound mailing list
> Sursound@music.vt.edu
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmail.music.vt.edu%2Fmailman%2Flistinfo%2Fsursound&amp;data=02%7C01%7C%7C880a958762324ad22ac808d603a71cca%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636700413605498803&amp;sdata=XyLmjx2mOOdApTO%2FBIrFR0Mzo%2FYnFvCW4Pes6Do7U3w%3D&amp;reserved=0
>  
> <https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmail.music.vt.edu%2Fmailman%2Flistinfo%2Fsursound&amp;data=02%7C01%7C%7C880a958762324ad22ac808d603a71cca%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636700413605498803&amp;sdata=XyLmjx2mOOdApTO%2FBIrFR0Mzo%2FYnFvCW4Pes6Do7U3w%3D&amp;reserved=0>
>  - unsubscribe here, edit account or options, view archives and so on.
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: 
> <https://mail.music.vt.edu/mailman/private/sursound/attachments/20180817/2db3da37/attachment.html
>  
> <https://mail.music.vt.edu/mailman/private/sursound/attachments/20180817/2db3da37/attachment.html>>
> _______________________________________________
> Sursound mailing list
> Sursound@music.vt.edu <mailto:Sursound@music.vt.edu>
> https://mail.music.vt.edu/mailman/listinfo/sursound 
> <https://mail.music.vt.edu/mailman/listinfo/sursound> - unsubscribe here, 
> edit account or options, view archives and so on.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: 
<https://mail.music.vt.edu/mailman/private/sursound/attachments/20180817/42de1686/attachment.html>
_______________________________________________
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.

Reply via email to