Can you explain what dB is?

Question

Hi everyone, I have a camera microphone that has a button where you can move the dB from 0 to -10 to -20, but exactly what does that do? .. pardon my ignorance but I don't know, does it reduce sound being brought into the recording? does it reduce bass?

Answer 1

dB is decibals i think that it reduces the sound coming in.

Answer 2

You're not ignorant.  The thing called dB is hard to understand and confuses a lot of people.  A dB or decibel, is a measurement of gain or loss of a signal.  0 dB is unity gain, no amplification or loss.  Any minus (-) dB is a loss and any plus (+) dB is a gain.  A dB is also logarithmic in nature, not linear.  When your switch is in the 0 position, it means there is no reduction in the signal.  The -10 to -20 means that the signal is attenuated by a factor of 10 to 20 dB unless you meant the switch has three positions, a 0 dB, a -10 dB, AND a -20 dB.  The attenuation should be flat across the frequency range of the mic.  If the switch is in the -10 dB position, the signal is one tenth (0.1) the strength of the original.  If the switch is in the -20 dB position the signal is one one-hundredth (0.01) the strength of the original signal.  If the one position is a -10 to -20 setting, then the signal will be only one tenth to one one-hundredth the strength of the unattenuated signal.  You just don't know if it will be one tenth, on thirtieth, or one seventy-fifth of the unattenuated signal, etc.

Answer 3

This reduces the 'Sensitivity' of the mike (dB is decibels)  indicating 'Sound Pressure' or how loud the sound is. This controls how much sound the mike will pick-up WITHOUT distorting it - the higher # indicate Less Sensitivity (Hence the '-' Minus symbol) this should cover all frequencies including 'Bass'.

Hope This Helps.