Adjusting multiple files -> creates electrical *pop* at end


I’m working with Audacity 2.0.6 in Windows 7 environment. (FWIW I also have access to macOS 10.12.1 and Win 10, if either of those might resolve this issue.)

I have multiple sound files from various sources - including WMA, AIF, MP3, and WAV.

I want to, in my layman’s terms, normalize/equalize all the sound files so they’re within range of each other; currently some are louder than others, etc.

I’ve read a few threads; including this 2010-era thread on using the Amplify Effect:

Doing that, then exporting everything as ‘WAV (Microsoft) signed 16 bit PCM’ format, the tracks all sound very good - however each track now has a horrible electrical pop at the very end of it.

This pop does not appear if I re-import the same WAV files back into Audacity, but is highly noticeable in VLC.

So. Is there a preferred method for bringing multiple files within range of each other, and exporting them or saving them in a way that this electrical pop is not present in the file or transition between files? Is this something specific to VLC or will it translate to a CD burn, for example? I’m slightly confused why I’m hearing artifacts in some programs but not others, but only with files exported from Audacity, not in the original audio files.

Thanks in advance for any advice and assistance.

A click or pop at the beginning or end (where there’s otherwise silence) is usually due to [u]DC offset[/u]. You can’t actually hear DC (zero Hz) but when the DC offset suddenly goes-away at the end of the file you’ll hear a click.

You can try the DC offset removal methods, or add a short fade-out (maybe 50 milliseconds or so) at the end.

NOTE - Under certain conditions, the Remove Offset feature of the Normalize effect can actually add offset to the beginning & end while removing the overall/average offset.

Changing the volume/amplification shouldn’t create an offset, but boosting the volume will make it worse.