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Notes on MKH-80 & MKH-800

Subject: Notes on MKH-80 & MKH-800
From: Walter Knapp <>
Date: Thu, 23 Jun 2005 19:04:01 -0400
My error on the switchable polar patterns available for the MKH-80 &
MKH-800, they also have supercardioid, so the list is:

omni, wide-cardioid, cardioid, supercardioid, figure-8

The store ad link provided earlier might lead to some confusion as to
self noise if one looks at the max SPL and dynamic range they list. The
max SPL listed is with the preattenuation on. The self noise of the two
models is 10 dBA, and the sensitivity is 40 mV/Pa. The two models only
differ in the max frequency spec.

The MKH-800 is designed to match the higher sampling rates some seem to
want to use. Most mics are not designed for the higher frequencies of
those sampling rates. The MKH-800 is a redesigned MKH-80, and if you
don't see any value in frequencies above 20khz, you can save a fair
amount hunting up the MKH-80's.

Note these are half the diameter of the Rode NT2-A, and 1/6th the
weight. I have my MKH-80s mounted in a Rycote stereo suspension and
zeppelin, but with some work it might be possible to cram the pair into
a mono setup.
http://frogrecordist.home.mindspring.com/docs/my_ms_setups.html

Here's some more info/propaganda from Sennheiser on the current MKH
series from their mic brochure:

> Operating Principle of the RF Condenser Microphone
> RF condenser microphones constitute a unique, sophisticated class of cond=
enser
> microphones. They fulfil the very highest demands made on sound quality a=
nd
> versatility, and are renowned for their high quality, highly accurate sou=
nd
> reproduction, ruggedness, all-weather operation, wide frequency response =
and
> extremely low inherent self-noise.

> Usually, a high capsule polarisation voltage would be necessary, however,=
 RF
> condenser microphones use a comparatively low RF voltage, generated by a =
low-noise
> oscillator. It is modulated by the capacitance changes produced by the so=
und
> waves moving the capsule diaphragm. Following the demodulation, a low-noi=
se
> audio frequency signal with very low source impedance is available, which=
 can be
> used to directly drive =91ordinary=92 bipolar transistors.

> As bipolar transistors produce less random noise than the field-effect tr=
ansistors
> usually needed, electrical equalisation technology can be included to inc=
rease the
> microphone=92s dynamic range and linearise its frequency response. As a r=
esult, an
> excellent low frequency response can be achieved even with small capsules=
, which
> would normally only be possible using larger capsules. In addition, small=
 capsules
> achieve a considerably better high frequency response than large capsules=
.

> The RF process results in a considerable reduction of the electrical impe=
dance of
> the capsule and enables RF condenser microphones to be operated in all we=
ather
> conditions. A further advantage of this process is that an ungrounded aud=
io
> frequency signal is available although the capsule is grounded. This is w=
hy all RF
> condenser microphones possess a genuine fully floating, balanced output w=
ithout
> having to use an audio frequency transformer.

> Sennheiser=92s Revolutionary Symmetrical Microphone Capsule
> The MKH 20 to 800 microphones have Sennheiser=92s unique and revolutionar=
y
> symmetrical push-pull capsule. Besides the normal back plate, this capsul=
e is fitted
> with an additional front plate, with the diaphragm being positioned betwe=
en them.
> Both plates are acoustically transparent. Any impedance changes in the ai=
r gaps
> between the diaphragm and the respective plate are opposite and therefore=
 cancel
> each other out, which leads to an unchanging acoustic impedance. This bal=
anced
> design produces extremely low distortion figures and a higher capsule out=
put that
> gives a much lower noise figure. The result is a microphone series unmatc=
hed in
> clarity and neutrality.

Note, the symmetrical capsule is one of the changes in the latest MKH
series, earlier MKH have more conventional looking capsules. This might
make the newer capsule somewhat more vulnerable to liquid water dripping
directly on the capsule than earlier designs. The MKH-30, MKH-80 and
MKH-800 would probably be the most vulnerable due to their more open
protective mesh. Rob noted a MKH-30 having some moisture problems, if
his windscreening is not stopping dripping liquid water, that could be a
problem. In a rain situation I always use mine with at least a standard
zeppelin for protection, which would make it unlikely that water would
drip through onto the mic. Anyway, if it was raining that much, I'd
probably stop due to the interfering noise. Or find better cover.

Walt




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