Re: [Sursound] Are mems a good choice for ambisonic microphones?
On Wed, Apr 13, 2016 at 06:01:57PM +0200, Bo-Erik Sandholm wrote: > The equivalent noise for a single mems mic is 31 dba, the example using 16 > mems would give an improvement of 12 dB getting to 19dBa which is equal to > the Tetramic spec. Only for the W signal. For X,Y,Z you'd gain 4 dB less and then only in a narrow frequency range. As frequency goes down, noise on X,Y,Z will increase by 6 dB/octave. Things will be worse again for higher order. And IIRC, for the Tetramic 19dB(A) is the spec for a single capsule. > I am not so certain about the actual mathematics about it, but what would > be the result of having the mems distributed along straight lines in a 3 > dimensional cross on thin "sticks" instead of a circular flat pool? When using a solid sphere the diffraction at mid/high F helps to create the wanted directional response. That would not be the case for a 'open' construction. Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow) ___ 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.
Re: [Sursound] Are mems a good choice for ambisonic microphones?
The equivalent noise for a single mems mic is 31 dba, the example using 16 mems would give an improvement of 12 dB getting to 19dBa which is equal to the Tetramic spec. i have had a idea that have never gone any where, that is to create a true b-format mic and using a number of "normal" mic capsules. Using mems might even be better`? we need a omni and 3 eights to get full FOA. But to create a horizontal b mic we only need a omni and 2 figure 8's. That could be created using a lot (16 or 32) of mems on a single circuit board in one dimension :-) And a number of the mems signals could be reused to create the needed signals, The mems pool signals could be used as insignals to 4 separate beam forming processing channels to create 4 cardoids ( or should we aim for just 2 figure 8ights instead) and one omni channel at the same physical point in space. Maybe we could even use different diameter mic pools for different frequency ranges? i think that using a larger diameter pool of mems would work better in low frequency bands. In addition the virtual mics created would always be centered at the exact same physical location. I am not so certain about the actual mathematics about it, but what would be the result of having the mems distributed along straight lines in a 3 dimensional cross on thin "sticks" instead of a circular flat pool? I think this could be very interesting ways to create mic for different directionality. Bo-Erik 2016-04-13 16:25 GMT+02:00 Marc Lavallee : > > I'm looking at this product here: > http://www.invensense.com/products/analog/ics-40300-3/ > > I wonder if mems are good for building an ambisonic microphone... The > document named "Low-Noise Directional Studio Microphone Reference > Design" shows an array of 32 mems. > > -- > Marc > ___ > 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. > -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20160413/cade900b/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.
Re: [Sursound] Are mems a good choice for ambisonic microphones?
Note the equivalent input noise of 31dBA. It's going to take a fairly large array of these to get the noise to an acceptable level. Cordially, Rudy Chalupa Pleiades Audio + Electronics -Original Message- From: Marc Lavallee To: Surround Sound discussion group Sent: Wed, Apr 13, 2016 10:27 am Subject: [Sursound] Are mems a good choice for ambisonic microphones? I'm looking at this product here: http://www.invensense.com/products/analog/ics-40300-3/ I wonder if mems are good for building an ambisonic microphone... The document named "Low-Noise Directional Studio Microphone Reference Design" shows an array of 32 mems. -- Marc ___ 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. -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20160413/014abce3/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.
[Sursound] Are mems a good choice for ambisonic microphones?
I'm looking at this product here: http://www.invensense.com/products/analog/ics-40300-3/ I wonder if mems are good for building an ambisonic microphone... The document named "Low-Noise Directional Studio Microphone Reference Design" shows an array of 32 mems. -- Marc ___ 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.
