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Re: single microphone on two channels with different level

Subject: Re: single microphone on two channels with different level
From: "Gianni Pavan" gpavan1960
Date: Fri Jun 3, 2016 12:54 am ((PDT))
Hi Paul, I agree with all your consideration. I'm constrained to use a
relatively cheap, low power and small recorder to record for a long period
of time. 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
128GB and 200GB microSDXC formatted in FAT32 (it is declared SDHC
compatible, not 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 have two levels recorded, one for far animals and
environmental noise and one 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
condenser to block the DC on the attenuated channel ?

Gianni

2016-06-02 23:21 GMT+02:00 'Paul Ahier' 
[naturerecordists] <>:

>
>
> Hi Gianni,
>
>
>
> I wonder if you really need to record two channels.  If you are using a
> quality 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
> microphone 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 woul=
d
> also almost 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 c=
an
> 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 a=
nd
> preamp to calculate the right resistor values (or you could just guess!).
> This is one major advantage of a professional grade recorder such as Soun=
d
> Devices or Zaxcom, you can feed one mic input to two channels and adjust
> channel trim 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
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sound is worth a thousand pictures." R. Murray Schafer via Bernie Krause.



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