Twotrack studio recorder - Google Play

Twotrack is a simple, powerful audio recorder that allows overdubbing and mixing to a stereo master track. It's ideal for musicians who want to record a rhythm track to play over, or it can simply be used for higher quality recordings than the standard voice recorder.

Record, then mix it to the master track (known as "bouncing" in the old school!), then record something over that, mix it, and keep going until you have all the parts you want.

Use it for multitrack recording and music production on the go or for recording quick ideas in your home studio! Used widely by rappers, musicians and songwriters for vocals, beatboxing, guitar, and other instruments. Great for rap, great for practicing.

When overdubbing, it's important to use headphones.

Features:

recording in 16 bit 44.1kHz wav file format
adjust the timing of your overdub to the master track
single level undo
import mp3 and wav files
export as mp3
free version is fully functional - just has ads as well
records in the background as a service, so you can play to a metronome or loop, or check your mail

Library and license info:

Twotrack uses the open source libmobailmusik library (https://github.com/motekulo/libmobailmusik), which is released under the Apache 2.0 license:
http://www.apache.org/licenses/LICENSE-2.0