sensitivity, gain V.S noise

Z

Zuu

New member
Hi, my aim is to record silent and distant sounds as loud as possible without noise (less as possible).
So understanding how sensitivity and gain affect recording will help a lot. How far I understand more gain means more noise (with noise I mean this artificial hiss). Is it true that more sensitivity mens louder recording, but without noise(or at least less noise)? Further more, microphones have certain sensitivity and some pro recorders also have sensitivity control settings - what does it mean? that recorder somehow control microphone sensitivity or there is another independent sensitivity controlling possibility? And finally how gain can help here?
 
Sensitivity = how low a volume sound can be 'heard' by the device (i.e. registers at some voltage in the input circuit).
Gain = turning up the signal.
Noise can be from the environment or from the equipment.
 
Or put another way-
The mic's sensitivity is voltage output per a given sound level
AT5040 -a very large diaphragm example 56.2 mVolts at 1 Pa (90dBSPL
Earthworks QTC-30 -very small diaphragm 30mVolts at 1 Pa
And as was said 'Gain = turning up the signal' = adding amplification making the preamp more sensitive to that given voltage.

I guess this is still incomplete though as the mics also have an electrical gain element so there would be it's signal to noise level relative to a given sound level.

..and lest we forget- free non electrical gain
Google Image Result for http://3.bp.blogspot.com/-auBG2u6acrQ/Tsv9k6Zmn1I/AAAAAAAAA3A/tOXPSjtxbC4/s1600/IMG_6527.JPG
 
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You will want a microphone with low self noise, as the self noise will be amplified along with the audio. You will often find this specified in units of dBA, and lower number=lower self noise.
 
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