Hi Paul, the Eigenmike captures 32 channels of input from 32 omni-directional capsules as positioned centrally on facets if the 8.4cm diameter sphere were a truncated icosahedron. 32 channels, 4th order capture (n + 1)^2. The mic captures a spherical harmonic deconstruction of a soundfield on the spherical baffle. The beamformer processing is done under VST or through Eigenstudio software. The Eigenbeam can be steered with 180 degrees of elevation and 360 degrees of azimuth with several selectable patterns; cardioid, super and hyper up to 3rd order, omni, dipole and torus. The captured spherical harmonic information from all 32 channels is rendered directionally in the Eigenbeamformer as selected for to up to 16 outputs, 3rd order. Due to spatial aliasing caused by capsule size and distribution the processing is split into two modes above and below 9kHz. In the paper, "Handling Spatial Aliasing in Spherical Array Applications" by Meyer and Elko, the designers discuss approach es to address this, although nothing specifically states how it was achieved in the EM.
The first four channels on the EM are dependent on element positioning on the baffle (not available in latest release notes online) so they don't correspond directly to the design of the Soundfield mic. Through mh's beamforming the W,X,Y,Z could be generated through dipole steering and omni although I've never attempted to render that output. Cheers, Anthony Tucker SID: 309278198 PH: 0411 303 339 ________________________________________ From: sursound-boun...@music.vt.edu [sursound-boun...@music.vt.edu] on behalf of Paul Power [pro_powe...@yahoo.co.uk] Sent: 02 May 2013 19:20 To: sursound@music.vt.edu Subject: [Sursound] Eigenmike Hi all, Just wondering if anyone could give me any information on how the Eigenmike works, since there is not allot of information available. I am very familiar with the Soundfield mic and how it generates the directional information W,X,Y, and Z through three FO8 patterns and an omni, this being in the form of four audio signals which are combined in different amplitudes and phase depending on speaker location, however regarding the Eigenmike it generates 25 audio signals which corresponds to 4th order? I understand that eigenbeams can be formed and pointed in any direction, however what are the pick up patterns of each capsule? and does the signals that you get from the mic correspond to say the way the Soundfield mic works, (excuse my simplistic idea) for example are the first four channels of the Eigenmike W,X,Y and Z for example? Thank you in advance, Paul Power -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20130502/8ada69e8/attachment.html> _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
