My first attempt with the free version. I recorded at my desired volume level but playback is much lower volume. There is a volume slide in the filmstrip icon and I have it at the highest level. There is a velocity slide in the pencil and paper icon but it reverts to zero at playback. The posted videos from people here all play nice and loud at my normal speaker setting, but for my recorded tracks I have to turn up my speakers way high. I'm afraid they will upload to YouTube at a too-soft volume.
Oh, one more thing. When I play my keyboard, the app plays the sound from my keyboard and also the sound from the app's keyboard as well. The two sounds together are quite annoying, but I recorded anyway and only the keyboard's sound plays on playback. That may contribute to the low volume???