Blip Synthesizer is a fun app that doesn't require musical knowledge to play.

The interface is a grid where each row is for a note in one octave, and each column represents notes in a pair of 4-beat pattern in a loop, and each column contains 8 polyphonic tones.

Use the slider at the bottom to alter the playback speed - it will display the tempo.

You can add and remove notes, change scales, change tones, all while music is playing.

Related Hardware:
Cheap Synthesizer Roundup

Changes in v1.2

• Add a list of preset sound (Simple Tone, Chine and Harmonica)
• Improved preference screen