Noisy Room - Theoretical Question

So I’m forced to record some audiobooks in a noisy hotel room with a noisy laptop (fan sound).

After I record the audio, I have to blow up the WAV using the ACX specs here:

  • Effect > Equalization > Select Curve: Low roll-off for speech, Length of Filter: about 5000 > OK.
  • Effect > RMS Normalize: Target RMS Level -20dB > OK.
  • Effect > Limiter: Soft Limit, 0, 0, -3.5dB, 10, No > OK.

So here’s my question:

If you absolutely must record in a room with lots of background noise (constant hum), then is it better to keep the Audacity microphone “Recording Volume” slider low? Or is this just superflous.

In other words, since i’m in a noisy room, and i need to post-process all this audio anyway, is it better to set that “Recording Volume” slider to a small value (like .10) – working under the theory that, perhaps i “won’t pick up as much” of the room noise. (As I would if I were to set the “Recording Volume” to .50 for example).



Let’s say that in the noisy room, you set the recording level such that:

Case 1:
Peak level of your voice = -6 dB
Peak level of noise = -46 dB

If you then amplify the track so that the peak level of the voice is -3 dB (ACX specified level), then you have amplified the track by +3 dB
( -6 +3 = -3)

Because you have amplified the track by +3 dB, the noise level is now -46 +3 = -43 dB.

Case 2:
You turn down the recording level 10 dB lower.
Peak level of your voice is now = -16 dB
Peak level of noise is now = -56 dB

To get the voice level up to -3 dB, you now need to amplify by +13 dB.
After amplifying by +13 dB:
Peak voice level = -16 + 13 = -3 dB
Peak noise level = -56 + 13 = -43 dB

Recording at a lower level has given no improvement. In fact, it will produce slightly worse sound quality, because you have used less of the available dynamic range while recording.