Microphone attenuation

microphone-attenuation

Microphone attenuation

Why would you want to use microphone attenuation a pad (an attenuator that reduces the signal level, usually by 10 or 20 dB)?…..
Because the sound coming into the microphone is very loud and is likely to overload the mic pre-amp in the mixing console/ or external mic pre-amp, or perhaps overload the miniature internal amp in the mic itself. In either case the result will be a distortion of the signal…not nice.
Modern microphone capsules can cope with extremely loud sounds – so loud in fact you would suffer permanent hearing damage if your ears were exposed for too long. Probably the worse case would be kick drums and guitar cabinets, but an operatic soprano at close range is pretty loud too.
Firstly, the capsule of the microphone has to be able to handle the level or there is nothing that can be done to rescue the signal. It would be unlikely that the capsule would be damaged, but there is the possibility of distortion. That would be a rare situation.
Much more likely is the possibility that the capsule of a condenser microphone will put out too much signal for the internal amplifier of the microphone to handle. In this case, the distortion is actually coming from the microphone itself, so inserting a pad at the mixing console will not help.
So if the mic has a pad switch, click the pad in. This will cut down the signal before it gets to the mic’s internal amplifier. If the mic doesn’t have a pad, then you’ll have to back it off from the sound source. (IE: instruct Kiri to sing more quietly please…or more practically move the mic further back from her)
But suppose that the signal from the mic is high, but the internal amplifier isn’t clipped. You have turned the gain all the way down on the preamplifier in the mixing console (or external pre-amplifier) and the level is still too much.
You could still click in the pad on the mic, but it would actually be better to use the pad on the console. Why? Because this will not only reduce the level of the signal, it will reduce the level of the noise produced by the microphone’s internal amplifier. If you use the pad on the mic, it will actually degrade the signal-to-noise ratio as the noise from the internal amplifier comes through at full blast.
It is all about signal path levels. Granted, this example will reveal only a subtle difference. But if you understand what the difference is and why, then it shows that you are in charge of the sound engineering process and have the ability to work to high standards of noise management.Therefore you should go read up on microphone attenuation elsewhere to really get to grips with the process.

Leave a Comment: