On 03/15/2012 03:16 PM, Giuseppe Silvi wrote:
Hi I'm Giuseppe from Rome,
i apologize if my question could be trivial, but I have this problem in my mind
to be solved.
If cardioid pattern is descrbed by equation:
cardioid = 1/2 ( 1 + cos Theta)
this is a fact.
and W equation is:
W = 1 / sqrt2
this is just a convention, which comes from the days of magnetic media.
i guess the observation was that in normal soundfield recordings, W is
usually a bit louder than X,Y, and Z, so in order to ensure optimal tape
saturation with maximal signal-to-noise ratio, W was reduced by 3dB
(that's the 1/sqrt2) before being recorded to tape. this way, you could
get roughly the same recording level for all 4 channels.
the -3dB convention is technically not necessary any more (which is why
the new proposed ambisonic standard does away with it). but it makes a
lot of sense to keep the old WXYZ format as it is, in order not to break
all existing recordings.
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