How do i amplify only small signals in an audio track

[stefaniecg]

I want to amplify only the little sounds, is there like a “Effect > Limiter” but a minimum limit?

[Seattle2k]

Use a ‘compressor’, to lower the ceiling of those loud sounds. Then, increase the overall gain, to bring everything UP. You can try Audacity’s “Compress Dynamics”

Alternatively, you can find an ‘expander’ VST on pluginboutique. There might be free ones available on the internet…I haven’t looked.

Alternatively, you could gate all the loud sounds out, then record the resulting quiet sounds to a new audio file/track. Then, increase the gain on the quiet track, before merging it back in with the loud hits.

Better yet…re-record with correct levels.

[DVDdoug]

The limiter with make-up gain may be what you want. The limiter “pushes down” the peaks and make-up gain re-amplifies them, and amplifies everything else too.

But it’s hard to say if you’ll like the results.

The amount of change you get depends on the current peaks and the threshold. If the peaks are below the threshold, nothing happens. If you apply it twice without make-up gain, nothing happens the 2nd time because the peaks are already at the threshold the 2nd time.

A limiter is a kind of fast dynamic compression. In general, dynamic compression makes the loud parts quieter and/or the quiet parts louder. In practice, most compressors make the loud parts quieter and then often make-up gain is used to “make everything loud”. (Automatic volume control is a slow-kind of compression.)

[Trebor]

@Seattle2k

Alternatively, you can find an ‘expander’ VST …

A dynamic range expander does the opposite of dynamic range compressor.
A compressor, (with make-up gain), is the tool for this job.

Some people confuse upward-compression with expansion …

Dynamic range compression | Types

[DVDdoug]

Right! Expansion makes loud parts louder and/or quiet parts quieter. The opposite of what you want.

You don’t see expansion used much in audio production, except for a noise gate which is a special kind of downward-expansion that turns down the volume, or kills the sound completely, when it gets quiet so you don’t hear the background noise.