# Amplifying only a section of a track

I’m a new user of Audacity 3.2.1.

I am having problems with amplifying a section of a track.

I have highlighted the section but when I apply the amplification, it appears to apply to the entire track, not just the highlighted section.

Also in some cases, the amount of current amplification is quite high, say 18…if I increase the amount to 20, instead of adding 2 units, it adds 20 units …

Appreciate help on this

Strange… It’s working for me (version 3.2.1) and I’ve never heard of that problem before.

Also in some cases, the amount of current amplification is quite high, say 18…if I increase the amount to 20, instead of adding 2 units, it adds 20 units …

Can you explain that a little more?

How are you checking the amount of actual amplification? (You can do that by running Amplify twice and checking the difference in the default amplification, and you can cancel the 2nd time if you just want to check.)

Existing amplification shows 14.9

If I adjust to 20, the new amplification is now 34

Existing amplification shows 14.9

If I adjust to 20, the new amplification is now 34

Sorry, I still don’t understand. There are two boxes and they are tied together so you can amplify BY a certain amount or TO a certain peak.

There is no “existing amplification” but Audacity has pre-scanned you file it knows the current peak (or the peak of the selection). Amplify will default new peaks of 0dB and whatever (positive or negative) change is needed for 0dB peaks. If the peaks are currently 0dB, both boxes will default to 0dB. (0dB of amplification is no change.)

I see a new peak of +15dB and amplification of +29.9dB, which means the peaks in your selection are currently about -15dB. Once you apply that amplification the new peaks of 15 are above the 0dB “digital maximum” which means (potential) clipping).

If you apply the amplification and then run Amplify again, it should default to a change of about -15dB, and a new peak of 0dB (as usual).

And I assume you realize that [u]clipping[/u] is distortion?

…Audacity itself won’t clip but your digital-to-analog converter is limited to 0dB and if the file goes over 0dB you’ll get clipping if you play at full-volume. Regular (Integer) WAV files and CDs are also hard-limited limited to 0dB.