Check to see if you get the same noise when you are mono with only the
mkh 30. If it is only when the two mics are connected and you can
varify it as an interaction then the solution can be easily identified.
Rich
--- In "stoatwizard" <> wrote:
>
> > My current conjectures are
> > 1) Perhaps something strange about the ATRAC compression (not too
> > likely, in my opinion) or
> > 2) (as stoatwizard suggested) something about the way the mics are
> > powered (an external box with 9 V battery and a few tiny electronic
> bits
> > I haven't identified yet).
> >
>
> Actually I have been chasing something similar, and I have come to the
> conclusion that I accused the thomann phantom unit unfairly. My MKH
> 30/40 are now
> powered off 6 8.4V batteries in series, with a diode drop of .6V to be
> about 50V. Within Sennheiser's spec of 48V+/-4V.
>
> I was recording a firecrest in a bush, and this is a quiet sound, so
> the HiMD was flat out. I have posted the raw recording and a sonogram
> on
>
http://www.suffolkbirds.co.uk/article/49/mkh-hf-noise-blues-firecrest-in-a-=
bush
> and there really does seem to be a lot of 17kHz wideband noise,
> particularly on the MKH30.
>
> I have got this down a bit by soldering jump wires from pin1 to the
> shell tag on the XLRs, but it appears to be very much like Steve's
> issue. Am I asking too much of these mics - would you normally expect
> the noise floor to exhibit a band of HF noise like this? No TVs within
> 100 yards, no computer at all, car ignition was off, not overhead
> power lines. There is a coastguard station about half a mile away with
> a VHF marine radio, but the 18kHz noise band is replicatable at home
> 20 miles from the recording site, just harder to see in the ambient
noise.
>
________________________________________________________________________
________________________________________________________________________
"Microphones are not ears,
Loudspeakers are not birds,
A listening room is not nature."
Klas Strandberg
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