Boosting volume of old tape

Sorry to ask something which is probably pretty basic but I am a complete amateur and would appreciate any help I can get. I had some old cassette tapes of family history digitized (by Kodak). There sent back 4 .wav files. 3 of them are fine. On 1, the volume is so soft it can’t be heard. I am looking for a way to boost the volume. Thanks for any help anyone can offer.

Try the Amplify Effect.

Audacity has already scanned the file and Amplify will default to whatever gain is needed for normalized (“maximized”) 0dB peaks.

Hopefully that will work but the “catch” is… You are limited (if you don’t allow clipping/distortion) by the maximum peak in the file/selection. So, one short peak(which may not even sound that loud) can will limit the amount of amplification. You may need to make shorter selections, or use the Envelope tool, etc., to even-out the volume.