At 14:19 2003-02-13 -0500, you wrote:
>Not quite right, I think. Mike noise doesn't exactly sum because of it's
>random nature; there is some natural phase cancellation that would occur.
>Klas could probably shed some light on this.
As you say, by random anti-phase cancellation, you get 3 db less noise ever=
y
time you double it. Two transistors of the same kind in parallel make 3 db
less noise than one transistor.
>
>Remember too that there is probably a slight PZM effect introduced by usin=
g
>a barrier and keeping the mike elements close to the barrier. Far from a
>perfect PZM, but perhaps there would still be some additional noise free
>gain.
>
>I think if you use very low noise mikes to begin with, such as the MKH20's=
,
>then stereo parabola is the way to go. If you then find it necessary to su=
m
>to mono, the result will sound extremely close to a mono parabola using th=
e
>same mike.
>
>At least that's my conclusion. Maybe I'm wrong.
>
>Klas?
I can't say, as two MKH20 in a parabol will be something very different the=
n
what I am used to, and have evaluated. See my description about how the
stereo DATmic works.
If you sum two mic's, the membranes have to be very close, otherwise you
loose the high frequencies by anti-phase cancellation.
Klas.=20
Telinga Microphones, Botarbo,
S-748 96 Tobo, Sweden.
Phone & fax int + 295 310 01
email:
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