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Re: Bottoming-out revisited

Subject: Re: Bottoming-out revisited
From: Estelle Sandhaus <>
Date: Thu, 26 Jan 2006 14:44:53 -0800
Hi all:



I have been following this thread, and have a novice technical question tha=
t
has been touched on here. I am using an old machine, the DA-P1, with an
AT835b, to record giant panda vocalizations in a captive setting. I
understand that there can be problems with signal distortion when the input
is too high.



What I am less clear on is the issue of distortion that has been reported t=
o
occur at lower gain knob settings with the DA-P1 (and certain other
machines).  I have seen advice in some older music forums to use the -20db
attenuator in situations where one is forced to set the gain knob
below 3.5to stay within headroom. I have indeed encountered this
situation while
recording certain vocalizations.  I think I understand from these posts
(please correct me if I'm wrong) that the distortion occurs in this case
because the attenuation from the gain knob in the DA-P1 is happening *after=
*
the signal has already reached the mic preamplifier. I have two questions.
1. How does the -20db attenuator work =96 what exactly does it do here? 2. =
Are
there any drawbacks to using it when the recordings are to be used for
bioacoustic analysis?



Thank you, and I do apologize if this has been addressed before!! As always
I continue to learn a LOT from everyone here =3D)



Estelle


On 1/22/06, Klas Strandberg <> wrote:
>
> The cause is probably that the first input transistor distorts the signal
> when the input is too high. As when you use a Telinga with an old recorde=
r
>
> (like the Tascam DAP1) without the -20 db attenuation.
>
> The attenuation needs to be made before the input of the recorder. As it
> is
> unbalanced, this can easily be made with two resistors only.
> It doesn't help to reduce the gain of the recorder. The signal is already
> distorted.
>
> Klas.
>
>


[Non-text portions of this message have been removed]



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