I think you probably do have a good chance of being able to do this using conventional beamforming techniques but with the following provisos:
- Given the mic spacing, the beams will only be accurate at frequencies below about 2kHz - You will need to assume that the mics are omnidirectional and do not shadow each other - Some height information could be derived but not very accurately and there will be an upwards-downwards ambiguity For an idea of the processing required, you may find this paper useful: https://www.researchgate.net/publication/44035458_Sound_Field_Recording_by_Measuring_Gradients Best wishes Tim -----Original Message----- > Hi All > > I am wondering how I go about converting a recording made with a 16 > microphone array into B format? > > I have downloaded the 16 channel recordings of noise from the DEMAND: > Diverse Environment Multichannel Acoustic Noise Database and would > like to play them back through an ambisonics rig. > > 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." > > The authors include a "MATLAB script which creates a 16 x 2 MATLAB > array with the xy coordinates (in meters) of each channel microphone > relative to the microphone of channel 1." > Weird ... ... must admit to _not_ having followed the link ... so perhaps mea culpa, ... but A MATLAB script might be a courtesy to those that use MATLAB, but we are only talking about 30 numbers ... akin to "see the attached Word(TM) file for my postal address" ;-)> All the mics are in a horizontal plane(?) and the sounds presumably(??) mostly off to the sides. So you can only (at best) extract pantophony (2-D ambisonics). To record that you would only have needed 3 (or 4) mics _as_close_together_as_possible_. To extract something from (some of) the sixteen: -I'm not optimistic -you'd need to know about polar patterns, directions, whether they shield each other, ... If you don't get a better reply I'm happy to visit the link and be more serious ... but on this list there is usually someone who's already (with success, or not) 'been down that route'. Michael > I don't have MATLAB, but I'm assuming that somehow I can still use the > positional information from the array, but I confess I don't know what > the process is or what software is required. > > Any guidance would be most appreciated. > > The website for DEMAND is: http://parole.loria.fr/DEMAND/ > > With kind regards > > Curtis Alcock > _______________________________________________ > 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.
