Hi Gianni,
There are plenty of tutorials on the web for building attenuators but I rea=
lly don=92t think you need to bother for a recording like that. Set a sens=
ible level, maybe a bit lower than you usually would and unless the deer is=
sticking its nose up against the microphone it will be fine. Engage the l=
imiters on the recorder just in case. You are making this more complicated=
than it needs to be.
http://www.uneeda-audio.com/pads/ I can=92t suggest values without knowing=
the impedance of the microphone and the recorder, but if you know those th=
ere are T-pad calculators online that will do it for you. Don=92t worry ab=
out the power, the microphone will only draw the current that it needs.
-Paul
From: =
.com]
Sent: 03 June 2016 08:54
To:
Subject: Re: [Nature Recordists] Re: single microphone on two channels with=
different level
Hi Paul, I agree with all your consideration. I'm constrained to use a rela=
tively cheap, low power and small recorder to record for a long period of t=
ime. My choice is the SONY M10 because of its quality (low self noise) and =
low power (70mA at 3V). It also has the valuable capacity to record to 128G=
B and 200GB microSDXC formatted in FAT32 (it is declared SDHC compatible, n=
ot SDXC). The drawback is that it can't record in mono to save space (e.g. =
to record 24 bits one channel). As I need one mic only I was wondering to h=
ave two levels recorded, one for far animals and environmental noise and on=
e for birds singing or deers roaring close to the recorder.
If you can suggest an attenuator scheme with resistor values I could try. I=
'm wondering about how this could interfere with PIP. Do I also need a cond=
enser to block the DC on the attenuated channel ?
Gianni
2016-06-02 23:21 GMT+02:00 'Paul Ahier' <paul.a=
> [naturerecordists] < <mail=
to:> >:
Hi Gianni,
I wonder if you really need to record two channels. If you are using a qua=
lity 24-bit recorder the dynamic range of the recorder will far exceed that=
of the microphone. In which case you can just put a 20db pad on the micro=
phone or reduce the input gain to avoid clipping and increase the volume of=
the quiet sections in post. In fact a 16 bit WAV recorder would also almo=
st certainly be fine unless you are dealing with HUGE changes in volume.
If you must record two channels. You will need to split the microphone feed=
with a Y splitter and then place an attenuator on one channel, you can buy=
these or you could make one with a simple resistor-based voltage divider. =
You will need to know the characteristic impedance of the mic and preamp t=
o calculate the right resistor values (or you could just guess!). This is =
one major advantage of a professional grade recorder such as Sound Devices =
or Zaxcom, you can feed one mic input to two channels and adjust channel tr=
im in software for exactly this kind of work. Maybe you know someone that =
would loan or rent one to you?
What is it you plan on recording?
-Paul
P.s. First post here, thanks for having me!
--
Centro Interdisciplinare di Bioacustica e Ricerche Ambientali
Universit=E0 degli Studi di Pavia
Via Taramelli 24, 27100 Pavia
http://www.unipv.it/cibra
http://mammiferimarini.unipv.it
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