This app was mentioned in 4 comments, with an average of 25.00 upvotes
Hmm, trying downloading this app https://play.google.com/store/apps/details?id=com.sokin.android.leon , set all the trem/vibrato settings to zero, and test out different frequencies. That's how I determined the information in the OP
Leon It annoys the hell out of my wife but I love playing with it.
No, I don't think so. Clicked the link you provided. I'll give it another try.