Can't find the vertical zoom function for audio files

HI, I am trying to match up two different audio files of the same footage and need to zoom them vertically, to see the wavelengths, so I can split them at the same exact place, so the audio matches, but I can't seem to find the way to do it.

If I double click on one of the files which is audio only, it shows up bigger in the source monitor (the other audio file, which is part of a bigger file, including video, doesn't even show up as a wave when double clicked, the video is what pops up in the source monitor). But there has got to be a way to get more than one audio wave vertically zoomed.

I've looked many places, and their explanations don't make sense. Please help!

Thank you in advance!!!

Ashot