Make audio louder online

How to make a quiet recording louder

The Amplify / Fade window opens as soon as your file has loaded.

1. Click Open a file to amplify, or use File ▸ Open… (Ctrl+O), and choose your audio file.
2. To raise only one part, such as a quiet speaker, select it first. With nothing selected, the change applies to the whole file.
3. Open Effects ▸ Amplitude ▸ Amplify / Fade… if it is not already open.
4. Pick the +3 dB or +6 dB preset, or type the same value in Initial Amplification and Final Amplification. Both go from -60 to +30 dB.
5. Press Preview and listen to the loudest passages. If they crackle or sound harsh, lower the value.
6. Click OK, then save the file with File ▸ Save As… in the format you need.

How much louder can it go before it distorts

A digital file has a ceiling at 0 dB. Amplify adds the same gain to everything, so once the loudest peak reaches that ceiling, anything more gets clipped: the tops of the wave are flattened and you hear crackle and distortion.

Before amplifying, open Analyze ▸ Statistics… and look at Peak Amplitude. If the peak is at -8 dB, you can add up to about 8 dB.

• +6 dB roughly doubles the level of the wave; +3 dB is a smaller, safer step.
• If you simply want the loudest peak right below the ceiling, Effects ▸ Amplitude ▸ Normalize… works out the gain for you.
• After amplifying, Possibly Clipped Samples in the same Statistics window should still read 0.
• During playback, the clip indicator next to the level meter lights up when the signal hits full scale. Click it to reset it.

When a few loud peaks get in the way

Many recordings have a few sharp peaks, such as a laugh, a cough or a snare hit, that reach the ceiling long before the rest sounds loud. Turning everything up will not help; tame those peaks first.

• Effects ▸ Amplitude ▸ Hard Limiting…: raises the level with Boost Input by and stops the peaks at Limit Max Amplitude to. The Loud Master preset adds 6 dB with a ceiling of -0.3 dB.
• Effects ▸ Amplitude ▸ Dynamics Processing…: a compressor that brings loud and quiet parts closer together and then adds Output Gain. The Gentle Vocal preset is a good start for speech.
• For one isolated peak, select just that moment, lower it with the -6 dB preset of Amplify / Fade, then amplify the whole file.
• Remove background noise before you amplify. Making the file louder makes the noise louder too.

Making audio quieter

The same window turns audio down: use negative values or the -6 dB preset. Lowering the level never distorts, but it cannot repair peaks that were already clipped when the file was recorded. For those, try Effects ▸ Noise Reduction ▸ Clip Restoration…, which rebuilds flattened peaks.