Your understanding is complete.
Answer to question 1/ The attenuation is placed before the first
(distorting) transistor and lowers the input to it.
Answer to question 2/ No. No drawbacks, except that "on the border"
(relationship between mic input self noise and mic output voltage) - you
may get more noise from the DAP1 mic amp, as you use more of it's gain
(incl. self noise).
At 06:06 2006-02-14, you wrote:
>Please forgive me for reposting this question, but I'm afraid it may
>have gotten lost on the long/old thread I had posted it on previously
>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 to occur at lower gain knob settings with the DA-P1 (and
>certain other machines). I have seen advice to use the -20db
>attenuator in situations where one is forced to set the gain knob
>below 3.5 to 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 =AD 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!
>"Microphones are not ears,
>Loudspeakers are not birds,
>A listening room is not nature."
>Yahoo! Groups Links
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S-748 96 Tobo, Sweden.
Phone & fax int + 295 310 01