Making audio louder with Audacity
(Tried with Audacity 1.3.12 beta.)
- Open the file in Audacity. Go to Effects → Amplify.
- The amplification set is already the maximum possible without clipping. Don’t change anything, just click OK
This makes the file as loud as possible without clipping: without the loudest parts of the “signal” getting lost. If the result is not loud enough, the problem is not with the loudest parts (they are already as loud as they can be), but with the softer parts. So you need a transformation that makes the soft parts louder while keeping the loud parts the same. This is Dynamic range compression: the dynamic range (difference between softest and loudest parts) is compressed.
So, after trying “Amplify”,
- Download “Chris’s dynamic compressor” from here (direct link).
- Save the file compress.ny in /Applications/Audacity/plug-ins
- In Audacity, go to “Effects → Compress dynamics…” (or perhaps it’s called “Compress &dynamics…”)
- The first control (“Compress ratio”) is the main one. Or just leave it as it is. Click OK.
- If still not loud enough, go back and increase Compress ratio. Of course, increasing it means decreasing the dynamic range — increase it too much and the parts meant to be soft will be no softer than the rest.