Re: [Sursound] Sursound Digest, Vol 82, Issue 2
If I remember correctly there was a fortran program written by Angelo Farina that could recover a ambisonic signal in 2 dimensions from a 5 microphone X setup. I mic in center and 4 mics in a square around that. I guess we could use just omni 4 mic's in a cross to get the needed information for creating horizontal XY signals. The closer the mics are to each other the higher the frequency resololution, and the longer they are from each other the better for recovering low frequency direectivity info - this is my theory. There have been figure of 8 mics created by using 2 capsules besides each other to extract the differential preassure gradient. BR Bo-Erik -Original Message- From: Sursound [mailto:sursound-boun...@music.vt.edu] On Behalf Of Curtis Alcock Sent: den 13 maj 2015 07:24 To: Surround Sound discussion group Subject: Re: [Sursound] Sursound Digest, Vol 82, Issue 2 It's still a dreadful mike, after using plenty of ressources to design a non-optimized WXY mike. Yes, the positions of the mics are really suboptimal to put it mildly. Many of them will just produce redundant information. Maybe it is only me, but what was/is the motivation to do things in that way? I suspect the motivation WAS to (deliberately) provide redundant information. The author writes that distance between microphones being 5 cm and the largest being 21.8 cm. So perhaps the goal is NOT to use all the information at any one time, but to provide enough versatility within the (library of) material for (random unknown) developers of noise reduction algorithms to test various scenarios specific to their needs. The algorithm developer could test differing beam-forming options that best met their own application by choosing which subset of the 16 microphones channels to use, depending on how great a distance they wanted between the (presumedly omnidirectional) mic ports, for example. And for developers to explore which combination of two (or more) mic ports provides optimal signal enhancement. But I'm just reading between the lines as unfortunately the website does not appear to explain any further. Which means that it's probably not necessary for me to use all 16 channels to convert to a B format file? Perhaps I only need to take a subset of the channels and use a matrix convolution software (I'm on Mac)? ___ 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 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] Sursound Digest, Vol 82, Issue 2
The strict answer to your question is in Gerzon's The Design of Precisely Coincident Microphone Arrays for Stereo and Surround Sound http://www.aes.org/e-lib/browse.cfm?elib=2466 There's a corrected copy at https://groups.yahoo.com/neo/groups/SoundfieldMic/files/Ricardo/. You might have to join. I used to be able to translate da maths to practical stuff but this Millenium my single remaining brain cell has given up. Aaron Heller Fons Adrieansen are your best bets. You need to know the polar directivity patterns of your 16 microphones and their 'exact' postion. Bet yus guys didn't know that paper was about more than Tetrahedral mikes :) It's just that in da old days, the computing power required was thought impossible eg the impossible task of 'tweaking' 16 complex (in both senses) frequency responses to get the (unknown) best match to the desired polar diagrams. Today, computing power is (usually) never a constraint and the much greater problem is knowing how to use it. I am wondering how I go about converting a recording made with a 16 microphone array into B format? ... 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. ___ 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] Sursound Digest, Vol 82, Issue 2
On Tue, May 12, 2015 at 05:24:10PM -, Richard Lee wrote: Aaron Heller Fons Adrieansen are your best bets. You need to know the polar directivity patterns of your 16 microphones and their 'exact' postion. Yep, directivity and exact positions. That would allow to compute a convolution matrix producing W,X,Y. As was already pointed out, the array is ambiguous w.r.t. up or down, so there wil be no Z. To do the processing you need a convolution matrix program. That will depend on your computing system (Linux, OSX, Windows), as will the exact format of the files to configure it. 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] Sursound Digest, Vol 82, Issue 2
Fons Adriaensen wrote: On Tue, May 12, 2015 at 05:24:10PM -, Richard Lee wrote: Aaron Heller Fons Adrieansen are your best bets. You need to know the polar directivity patterns of your 16 microphones and their 'exact' postion. Yep, directivity and exact positions. That would allow to compute a convolution matrix producing W,X,Y. As was already pointed out, the array is ambiguous w.r.t. up or down, so there wil be no Z. To do the processing you need a convolution matrix program. That will depend on your computing system (Linux, OSX, Windows), as will the exact format of the files to configure it. Ciao, It's still a dreadful mike, after using plenty of ressources to design a non-optimized WXY mike. Maybe it is only me, but what was/is the motivation to do things in that way? A question which seems to be valid, in this context... Best, Stefan ___ 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] Sursound Digest, Vol 82, Issue 2
It's still a dreadful mike, after using plenty of ressources to design a non-optimized WXY mike. Yes, the positions of the mics are really suboptimal to put it mildly. Many of them will just produce redundant information. Maybe it is only me, but what was/is the motivation to do things in that way? I suspect the motivation WAS to (deliberately) provide redundant information. The author writes that distance between microphones being 5 cm and the largest being 21.8 cm. So perhaps the goal is NOT to use all the information at any one time, but to provide enough versatility within the (library of) material for (random unknown) developers of noise reduction algorithms to test various scenarios specific to their needs. The algorithm developer could test differing beam-forming options that best met their own application by choosing which subset of the 16 microphones channels to use, depending on how great a distance they wanted between the (presumedly omnidirectional) mic ports, for example. And for developers to explore which combination of two (or more) mic ports provides optimal signal enhancement. But I'm just reading between the lines as unfortunately the website does not appear to explain any further. Which means that it's probably not necessary for me to use all 16 channels to convert to a B format file? Perhaps I only need to take a subset of the channels and use a matrix convolution software (I'm on Mac)? ___ 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.
