assuming all six capsules have same gain, and all are contributing to W, how much should be the attenuation? umashankar
i have published my poems. read (or buy) at http://stores.lulu.com/umashankar > Date: Sat, 26 May 2012 18:25:04 +0200 > From: [email protected] > To: [email protected] > Subject: Re: [Sursound] microphone epiphany ? > > On 05/26/2012 04:51 PM, Augustine Leudar wrote: > >> Hi Michael, > >> thanks for the reply - there is no doubt Ive missed something ! > >> I am aware of the need for W coordinate and have included it in my encoder > >> as instructed although I have to admit I am still not clear on its > >> function - but my question specifically relates to the information gained > >> from the 3 fig of eight patterns gained form a mic design such as this one > >> : > >> > >> http://www.shapeways.com/model/143678/velan-140-internals.html > >> > >> Am I right in thinking the W component gives you enhanced distance > >> information for a given sound source ? > > we cannot hear absolute phase, so if you are listening to a figure of > eight microphone, there is no way to tell whether the sound you're > hearing was coming into the (positive) frontal lobe or the (inverted) > rear lobe. hence, the only information we can get from a lonely fig8 is > "it's obviously not coming from the side". > > now if you add an omni to the equation, all of a sudden you have the > possibilty to discern between the two lobes of the fig8: one is in-phase > with the omni, the other isn't. > > thus, the 0th order component helps you resolve the ambiguities of all > the 1st order signals. > > btw, if you move to second order, the situation is the same: with a > cloverleaf directivity, you only know "it's either coming from > front-or-back, or from left-or-right". only with the first-order > information, the ambiguity can be resolved. > > W also has a subtle role in distance coding, but its main job is really > to help us make sense of the fig8s. > > > to wrap up, three real fig8s won't ever give you ambisonics. but if you > obtain the fig8s by subtracting two back-to-back cardioids, you can also > add them, which then gives you a nice omnidirectional component. note > that you will have to attenuate the resulting omni signal according to > the number of capsules you used. > > > best, > > > jörn > > > > -- > Jörn Nettingsmeier > Lortzingstr. 11, 45128 Essen, Tel. +49 177 7937487 > > Meister für Veranstaltungstechnik (Bühne/Studio) > Tonmeister VDT > > http://stackingdwarves.net > > _______________________________________________ > Sursound mailing list > [email protected] > https://mail.music.vt.edu/mailman/listinfo/sursound -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20120527/db077b8f/attachment.html> _______________________________________________ Sursound mailing list [email protected] https://mail.music.vt.edu/mailman/listinfo/sursound
