Misleading.
I tried this app and listened to a few of my songs from within the app and at 1st was very impressed at the sound quality when the effect is enabled. Within the app you can turn the effect on and off and the quality of all tracks was much improved with the effect on. But, I soon realized what was happening. My music sounds flat when listening from within the app with the effect disabled. But if I listen to the same track on my built in player on my iPhone the track sounds great without the app. So from what I can tell turning the effect switch off within the app intentionally degrades the sound quality of my track in effort to make the effect impressive. The switch does not compare the effect with the sound of my built in audio. Very misleading. I will not be keeping this app.
e.xman about
Boom: Bass Booster & Equalizer, v1.2.1