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  #16  
Old 10-22-2016, 11:49 AM
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rick-slo rick-slo is offline
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Originally Posted by ChuckS View Post
I agree with the intent of your post and everything up until "the 1 to 10 ratio stays the same". As the preamp gain is changed, the ratio of signal to noise does stay the same, but in this example the difference remains at 90 dB which is way way more than a 10:1 ratio (each 10dB difference is ratio of 10:1)
Right via logarithmic scale values. A three dB increase in preamp gain (doubling sound pressure level) would give 13 dB versus 103 dB.
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Last edited by rick-slo; 10-22-2016 at 04:38 PM.
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  #17  
Old 10-22-2016, 11:58 AM
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Originally Posted by ChuckS View Post
i agree with everything you say except where you added in the 7dB for sensitivity differences ( in your example). The way mic noise levels are spec'd, (in dB) relative to the mics level at 1 pascal already factors in the sensitivity differences. I'm not saying sensitivity is not meaningful, I'm just saying you don't add it inti e differences between mic noise spec levels.
You are correct as regards the mic alone, but you really have to consider the whole amplification chain. Where the sensitivity affects the final outcome is at the preamp, where for equal final volume you are required to add more gain on a mic with lower sensitivity.

I was trying to keep it relatively simple for the OP but still looked for a real-world example. Maybe I over-complicated it, huh?

Bob
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  #18  
Old 10-22-2016, 12:12 PM
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Originally Posted by Bob Womack View Post
You are correct as regards the mic alone, but you really have to consider the whole amplification chain. Where the sensitivity affects the final outcome is at the preamp, where for equal final volume you are required to add more gain on a mic with lower sensitivity.

I was trying to keep it relatively simple for the OP but still looked for a real-world example. Maybe I over-complicated it, huh?

Bob
i agree that the sensitivity needs to be considered, and maybe especially so in Anton's case because he is recording acoustic guitar and from what I remember he plays fingerstyle kind of softly.

There's been a lot of great stuff in this thread that could be helpful to many of us. I realize that I was being kind of anal in my posts on this thread, but that's who I am
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  #19  
Old 10-22-2016, 06:30 PM
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If you have a mic with X selfnoise and you amplify the signal with a preamp, the selfnoise increases. If you end up needing more gain than the preamp can supply without introducing more noise, get a more sensitive mic with the same selfnoise or one with equal sensitivity but lower selfnoise, or move the sound source closer.

The rest is just chatter.

Regards,

Ty Ford
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  #20  
Old 10-23-2016, 11:21 PM
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Thanks for the explanations everyone, that clears up alot.
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