> b) allows me to get an averaged
> sound level and frequency distribution spectrum for the 10 minute duratio=
n
> of the recording (using Raven 1.4); and
Hi Tim,
I would perhaps recommend to use single (calibrated) omni-directional micr=
ophone for this kind of analysis. As David already pointed out, summing up =
the two stereo channels of an ORTF array could lead to odd effects.
> The shotgun mics I have access too (Sennheiser ME66 and ME67) do not seem=
to
> be able to abstract to this extent. Maybe a better mic (SennheiserMKH8070=
??)
> may achieve this but sadly at the moment it's out of my league.#
No, for your particular application, the more expensive MKH series shotgun =
microphones will not provide any advantage because the pick-up patterns of =
all these models are quite similar. Actually, the MHK series microphones ex=
hibit a higher noise level at frequencies above about 10 kHz, which could b=
e a problem for your spectrographic analysis.
> I must admit to being a little worried about the frequent comments I come
> across in various areas of the scientific literature regarding supposed
> "colouration" of the sound by the parabola? Although both reviewing posti=
ngs
> on this list, and doing a little research of my own into the published
> literature, this does not seem to be a huge problem providing you are
> concerned with on-axis recordings of above the critical frequency for the
> dish diameter you are using. Or have I missed the point entirely somewher=
e?
Yes, you are right. There will be some coloration caused by the parabola, b=
ut as you explained, there are no alternatives under these specific circums=
tances. Even a recording made with a shotgun microphone can be affected by =
coloration effects as soon as there are reflections off the ground or nearb=
y vegetation.
> If I understand things correctly, there's no necessarily perfectly correc=
t
> answer for anything in this game; like in many fields, the answer is usua=
lly
> "it depends."
Absolutely!
Cheers,
Raimund
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