Pad vs lowering gain on mic preamp

  • Thread starter Thread starter armansrsa
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armansrsa

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So what is the difference really? If the source is loud why not just turn down the gain? If you want the saturation your preamp gives you maybe I can understand that but if you don't have a colored preamp, what is the point of the pad switch on a microphone?
 
Prevents overload,clipping,distortion in the active circuitry.

G
 
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armansrsa said:
So what is the difference really? If the source is loud why not just turn down the gain? If you want the saturation your preamp gives you maybe I can understand that but if you don't have a colored preamp, what is the point of the pad switch on a microphone?
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It's possible for the signal entering the preamp to be loud, relatively speaking, and maybe there are good reasons to do that sometimes,
but it's also possible for it to be hotter than the preamp can handle, resulting in distortion no matter where you set the gain.

A pad on a mic lets you take the analog mic output down 10/20/whatever db before the preamp to make sure you're well clear.
Very useful with capacitor microphones on snare drums, and that sort of thing.

Often you get pads on preamps/mixers too. As far as I know they're usually in front of the gain circuitry, so they achieve the same effect as a pad on the mic.

Hope that helps. :)
 
It's really useful on things like trumpets when the spl in front of the damn things can be horribly huge!
 
The better capacitor microphones use a capacitive voltage divider to attenuate the signal going into the the impedance converter.
Even better is a cap' divider plus some extra feedback as this keeps the self noise low.

Dave.
 
As already mentioned but perhaps not explicitly enough, it's possible to overload the active circuit inside a condenser mic itself, before the signal even gets to the preamp. The pad on the mic can prevent that.
 
what does an overloaded circuit in a condenser mic sound like? Does it have a characteristic glitch or artifact that can tell you it's happening?
 
bluesfordan said:
what does an overloaded circuit in a condenser mic sound like? Does it have a characteristic glitch or artifact that can tell you it's happening?
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That will depend upon the exact details of the circuitry (which few mnfctrs tell us!) A simple FET source follower will generate mostly 2nd harmonics unless grossly overloaded and that might sound quite nice in some circumstances.

Do not forget however that no cap mic will run into overload at less than around 100dB SPL and that is 'king loud so the finer points of "attitude" distortion will likely be lost in the row?

Dave.
 
If it does it, you'll hear it. Mic distortion is pretty obvious. One of mine actually makes a loud crack on all the peaks. Not at all a gentle distortion but a pretty nasty sound that you need to perhaps 'create' to hear and remember.
 
bluesfordan said:
what does an overloaded circuit in a condenser mic sound like? Does it have a characteristic glitch or artifact that can tell you it's happening?
Click to expand...

It's hard to describe but it generally is like a switch rather than a gradual thing that you might not notice at first.
Usually if you're overloading the microphone you're going to know about it.
 
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