SunVox is the most powerful music creation tool for Android. It is a small and fast cross-platform modular synthesizer with pattern based sequencer (tracker). You can read more info about the music trackers here: http://en.wikipedia.org/wiki/Tracker_(music_software)

[ Key features ]
• Modular interface.
• Powerful microtonal (ultra-chromatic) sequencer.
• Highly optimized synth algorithms.
• Support of 16/24/32bit WAV, AIFF and XI samples.
• Multitrack WAV export.
• MIDI import/export.
• Mic/Line-in recording.
• Real-time recording of any types of sound events.
• XM (FastTracker) and MOD (ProTracker, OctaMED) import.
• It is also available for other systems (Windows, Linux, macOS, iOS, etc.).

[ Brief instruction ]
The main menu - button with the SunVox icon in the upper left corner of the screen.
Use multitouch to scale/move content of timeline and pattern editor.
How to connect one module to another: first touch on source, second touch on destination.
REC button is only for notes and controller recording. If you want to record sound - use the Sampler module (and press REC button under the Sampler controllers).

Official SunVox homepage, user manual, video tutorials:
http://warmplace.ru/soft/sunvox

Publish your SunVox songs here:
http://soundcloud.com/sunvox

Known solutions for some problems:
http://warmplace.ru/android

[ Built-in synthesizers & effects ]
• Analog Generator;
• DrumSynth with 120 unique synthetic drum sounds;
• FM synthesizer;
• MetaModule (use it to build your own synths/effects);
• Sampler (supported formats: WAV, XI, AIFF);
• SpectraVoice (FFT-based synthesizer for warm atmospheric sounds);
• Side Chain Compressor;
• Distortion;
• Echo;
• 3Band equalizer;
• Filter (Low-pass, High-pass, Band-pass, Notch);
• Flanger;
• Loop (for glitch effects);
• Reverb;
• Vocal Filter (for human voice simulation);
• Vorbis Player;
• WaveShaper;
• and more ...