> At 19:55 1/6/2013, Sampo Syreeni wrote: >>On 2013-06-01, David Pickett wrote: >> >>What I take this to mean is that if one is using WXY (derived from >>A-format) for horizontal only playback, W will contain unwanted >>vertical information that should be discarded. >> >>Correct for W, but also for X and Y. That's not the end of the story >>either: you can't nicely and linearly subtract even the cleanest, >>purely up-down information from the signal set. If you try to do >>that by subtracting Z from W, it works for signals which come from >>above. But now signals coming from below are suddenly doubled. All >>you ended up doing is to put in a cardioid weighting on the signal >>set, and you can't have the cardioid pointing more than one way at >>the same time. That holds for the notional cardioid pointing in >>other directions as well, which shows you X and Y too are affected. > > So, to record horizontal-only ambisonics, does it follow that a > native-B approach of four cardioids or fig8/fig8/omni will give > inhrently better results than a tetrahedral array? >
Unless I am totally adled by today's rare sunshine ... : You can obtain either of those set-ups from the output of a tetrahedral .... just as you could get Blumlein from any of the three. (Tetraproc will do it for you, but you would need two passes (or two instances) to get four cardiods out (and then mix to get figure of eight). Omni is W ... unless you have a horizontal omni ... ?) In practice things like size and calibration must kick in, but -a terahedral is likely to be smaller -tetrhedral calibration is frequent, not sure about other arrays (though obviously possible). Michael _______________________________________________ Sursound mailing list [email protected] https://mail.music.vt.edu/mailman/listinfo/sursound
