You shouldn't need to go as low as -30 dB. Use a compressor and/or limiter and/or the envelope tool (http://manual.audacityteam.org/man/envelope_tool.html) to bring the audio to a more even level before you normalize the RMS.Breakfast wrote:I started out trying to normalise to -18 but when that kept pushing everything into the clip-zone I kept knocking it down until I got to around -30, at which point it stopped boosting the loud parts up past zero.
It depends on when you hit clipping.Breakfast wrote:I thought once you hit clipping you were sonic toast?
If you hit clipping during recording, then you are toast.
If you hit clipping on exporting, then you are toast (unless you export as 32-bit float, which is not generally recommended because few programs support 32-bit float audio)
If you hit clipping while working in Audacity, then you still have fresh bread (not toast), provided that your track is 32-bit float format (default).
One of the most useful features of 32-bit float format is that it doesn't stop at 0 dB, but can go on for hundreds of dB above the normal clipping level, so all you need to do to bring the audio back into the "valid" range (below 0 dB) is to apply the Amplify (or Normalize) effect with default settings.
As a demonstration:
1) Import some audio. Ensure that the track info panel says "32-bit float".
2) Apply the Amplify effect with default settings (the peak level is now 0 dB)
3) Apply the Amplify effect with +30 dB and the "allow clipping" option enabled. The peak level is now +30 dB and will sound very loud and distorted.
4) Apply the Amplify effect with default settings and "allow clipping" disabled, The peak level is now 0 dB and there is no damage.
Note, OGG and ALAC files will import as 16-bit and need to be changed manually to 32-bit float using the track drop-down menu (http://manual.audacityteam.org/man/audi ... tml#format)