Thank you for all the answers. I do appreciate. However, no one has answered my question. I will ask again.
Can someone point me to any published resources that explain the principles and theoretical equations required to in theory convert from 2nd order A-format to B-format? I can find resources for 1st order but not for 2nd order. Thank you. - martin On Tue, 26 Mar 2019 at 21:54, Fons Adriaensen <f...@linuxaudio.org> wrote: > On Wed, Mar 27, 2019 at 04:50:06AM +0800, Stephen McArdle wrote: > > > I think the question might be more simpler than this. > > For 1st order (with 4 microphones) the very first A to B > > equations are (for example): > > > W' = FLU+FRD+BLD+BRU > > X' = FLU+FRD-BLD-BRU > > Y' = FLU-FRD+BLD-BRU > > Z' = FLU-FRD-BLD+BRU > > It's not that simple. This would work if > > * your capsules are exactly hypercaridiod (i.e. max > directivity), independent of frequency, and > * they are *perfectly* matched. > > That is not the case in practice. Even if the capsules > are high quality and well matched you will need some > EQ in addition to these simple sums. > > > What would the equations be for 8 microphones? > > W' = FLU+FRD+BLD+BRU+FRU+FLD+BLU+BRD > > X' = FLU+FRU+FRD+FLD-BLD-BRU-BLU-BRD > > Y' = FLU+FLD+BLD+BLU-FRU-FRD-BRD-BRU > > Z' = FLU+BRU+FRU+BLU-FLD-BLD-FRD-BRD > > No, this is completely wrong, ignores all practical > aspects, and again it's not that simple. > > > But what about R’,S’,T’,U’ ?? > > Much more complex again. > > In practice you can't do this to sufficient accuracy > without rather complex EQ or convolution. > > And anyway, trying to do A/B conversion (or even Ambisonic > decoding) in environments like PureData, SuperCollider and > similar is a sure recipe for disaster. These are all > *artistic* tools, and they don't allow for the precise > technical definition of e.g. the required EQ. Apart from > that the probabily of making some simple but fatal error > is way too high for a reliable result. > > Ciao, > > -- > FA > > _______________________________________________ > 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/20190326/72c7a8db/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.
