This app is a great idea, and for the low price of $5 worth of in-app purchases I was able to do everything I wanted with the app, including messing with settings and viewing spectrograms in full-screen view.
But!...Then the app started crashing EVERY TIME I TRIED TO FULL-SCREEN (even though it worked fine the first day). I thought, "okay, I'll just uninstall and reinstall the app to see what happens."
Well, guess what? Now it wants me to PAY FOR THE IN-APP PURCHASES AGAIN! JUST TO CHANGE BASIC SETTINGS AND GO INTO FULL-SCREEN!!!!!
What a joke. I want my 5 dollars back! The features I paid for should be built-in in the first place, AND THEY SHOULDN'T CRASH THE APP!!!!!
Maybe there are other apps on the app store that display spectrograms for audio files WITHOUT all this nonsense. For now though, I'll stick with "Sonic Visualizer" on my PC; it's free, WAY more versatile, and it doesn't crash just because I tried to use its most basic and essential functions (even though it hasn't been updated since like 2007, it still works far more reliably than 'Smart' Juke.