How to amplify a quiet section without sudden jumps?

I simply want to amplify a very quiet section of my sound file, but the amplify tool has no ‘fade in’ so you get a sudden jump in volume.

And before you tell me to use the envelope tool, I can’t. For 3 reasons:

  1. The envelope tool only allows slight amplification, whereas my sound file needs significant amplification in places.
  2. If you’ve already used the envelope tool to correct low volume, it is difficult to then use the envelope tool the normal way to make subtle adjustments, since you can’t clearly see the shape of the envelope/waveform.
  3. I don’t want or need a “non-destructive” method of amplification. The sound is way too quiet and needs to be significantly amplified before I can start to work with it.

significant amplification

How significant?


I use the text-envelope plug-in to do this kind of stuff.
First, you have to choose the units for time and amplification.
Second, the initial and final amplification - usually 0 dB or 100 %.
Third, define the intermediate points.
Example: “10 200 -10 200” (if all units are %) would amplify the middle of the selection (the inner 80 %) by 6 dB (= 200 %).
The first and last 10 % have a linear fade up/down.
Of course, I don’t enter those settings always newly. Once the effect has been applied, you can repeat it with Control-R (Windows). The settings can also be saved as user presets - the last settings will be saved anyway.
I attach the file (put it into the plugin folder of Audacity and enable it with the Add/Remove menu under Effects)
TextEnvelope.ny (10.6 KB)
Try it out.
I could also provide you with a hard-coded version that amplifies e.g. by 3 dB and fade lengths of 0.5 s. Thus, no GUI would pop up any more and the effect would be applied immediately.
What do you think?

I’m doing that quite often… amplifying sections or selections. Many sound tracks are VERY poorly recorded or inserted in videos. Some audios or radio shows are poorly mixed, where the caller or guest isn’t `potted up´ and the levels are low.

So I use selections´ and do amplifies´ on those selections, volume jumps be damned. Also consider doing a COMPRESS (compression function) on the whole file. That’s on my `to do´ list, get familiar with the Compression parameters. If used correctly, a COMPRESS will solve the whole problem in one operation, depending on the levels involved.


p.s. you could also do a LARGE amplify (10 or more dB) on a selection, then do a Noise Reduction on it.

Thank you both for your suggestions.

I have posted an Audaicty feature request for an amplify ‘fade in’ setting, here:

Robert, I tried using the Text Envelope plugin but it is not for me. It requires manually entering numbers and I can’t work that way. I do a lot of sound editing and I need to be able to work quickly and see what I’m doing. A system of manually entering numbers is just not for me. I’d rather have jumps in volume to be honest.

Edwinn, as for using compression, thank you, but see the above link where I have explained why compression is not a good solution for me.

Could this work?

Select the bit you want to amplify
Click Edit > Duplicate
Amplify the duplicate
Use Adjustable Fade in/out on the duplicate if needed