David Pickett <d...@fugato.com> wrote:
>> How does one record in third order (or indeed any order above first order)? >> What kind of microphone array does one need, for instance, for 3rd order >> with no height information (WXYUVPQ)? >> Is there a "native format" method for HOA or is it all extended A format, >> with conversion through matrices? All excellent questions. It is not quite as obvious how to record any order of Ambisonics above first order. It will require some sort of microphone array and post-processing. One of my favorites is the array described by Craven, Lawe and Travis in: Microphone arrays using tangential velocity sensors P.G. Craven, C. Travis, M.J. Law We introduce a new class of 3D microphone arrays that use symmetrical arrangements of tangential velocity sensors. Use of velocity sensors allows these arrays to recover spherical harmonics of a given degree with less low-frequency boost than when using pressure sensors only. As an example we present a symmetrical array of twelve velocity sensors that resolves the eight harmonics of degrees 1 and 2. A second-order spherical microphone can now be constructed by combining this array with one or more pressure sensors that provide the missing harmonic of degree 0. http://ambisonics.iem.at/symposium2009/proceedings/ambisym09-craventravis-tangentialsphmic.pdf/at_download/file The other practical method for constructing an array that produces higher order spherical harmonic outputs is to use a group of omnidirectional microphones on a sphere, such as the commercially available Eigenmike: http://www.mhacoustics.com/products There are other methods. It's still early days for this technology. Eric Benjamin -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20131122/1436acf9/attachment.html> _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
