Hi JM-
Quiet locations require quiet mics if you want to avoid noise. The
commonest form of noise is "hiss." This noise stems from the mic
itself and thus termed, "self-noise." Some lower cost recorders can
contribute noise, but in 90% of the situations we discuss here, the
noise stems from the mics.
If you are curious how your mic performs noise-wise, look-up the
"self" noise" figures that the manufacturers have provided. You can
refer to this chart as well:
http://www.uwm.edu/~type/audio-art-tech-gallery/pages/MicSpecs-Cover.html
Audio Technica AT822 stereo 24 dB(A) 6 mv/Pa
The manufacturers' figures should not be relied upon in making
expensive decisions, but we tend to suggest on this list that a mic
should have no more than 16dB(A) self noise to qualify for recording
ambience in quiet locations.
If you insert _any_ mic preamp between the mics and the recorder, the
preamp will not remove or alter the "self-noise" that is being
generated by the mics. There will be no change
Basically, with 24dB(A) self noise, the AT-882 will produce quite a
bit of audible noise when you raise the gain to capture quiet
subjects. Coincidentally, the 822 is the same mic a highly regarded
audio pro recommended to me for recording nature sounds. It took me
several years to figure out why my recordings did not meet my
expectations. Not only was the noise considerable but it extends
across the frequency spectrum making it very difficult to filter
without making the recording seem "duller" than I wanted. The AT822
also also has low output (6 mv/Pa sensitivity) so if the recorder's
mic preamp does generate some background noise, it can become more
audible "behind" the mic's self noise. In general, mics with a
sensitivity reading of 12 mv/Pa or higher are moe suitable for nature
recording.
There are some mics with low self noise that don't cost a lot. Search
the terms, "AT-3032" and "NT1-A" through the list archive. Many audio
pros will start folks off with a pair of mics that cost less than the
recorder and, really, the better advice for nature recordists is the
opposite. Rob D.
= = = = =
At 9:55 AM +0000 2/18/08, jmcharcot wrote:
>Hello,
>
>I'd like to by a preamp to insert between my Marantz PMD-620 and an
>AudioTechnica AT-822.
>This would be mainly to record quiet ambiences, natural sounds.
>
>Which preamp would you the suggest?
>(BTW, I'm also interested in a small one..)
>
>I saw a few ones who could interest me :
>
>- CHURCH AUDIO ST-9100 STEREO MICROPHONE PREAMP
><http://cgi.ebay.com/CHURCH-AUDIO-ST-9100-STEREO-MICROPHONE-PREAMP_W0QQitemZ250198674711QQihZ015QQcategoryZ3281QQcmdZViewItemQQ_trksidZp1742.m153.l1262>http://cgi.ebay.com/CHURCH-AUDIO-ST-9100-STEREO-MICROPHONE-PREAMP_W0QQitemZ250198674711QQihZ015QQcategoryZ3281QQcmdZViewItemQQ_trksidZp1742.m153.l1262
>
>- There is also a smaller version but it has only +20 db, would it be
>enough acccording your experience?
>
>- SP-PREAMP-11 - SOUND PROFESSIONALS
><http://www.soundprofessionals.com/cgi-bin/gold/item/SP-PREAMP-11>http://www.soundprofessionals.com/cgi-bin/gold/item/SP-PREAMP-11
>
>- SP-PREAMP - SOUND PROFESSIONALS
><http://www.soundprofessionals.com/cgi-bin/gold/item/SP-PREAMP>http://www.soundprofessionals.com/cgi-bin/gold/item/SP-PREAMP
>
>Thanks a lot for your comments.
>
>Kind regards,
>
>JM.
>
>
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