S4 Rhythm Composer Pro is a beatbox that can be customized in various ways.
14 drum kits are preset, and also you can create and save the entire kit as "User kits" at your choice.

This app has various real-time effects.
This allows you not only to play a created pattern (song), but also to play music, controlling various effects in real time.

Specifications
- PCM Sound (Number of parts: 10)
- 14 preset drum kits
- Tempo: 30-300BPM, Tap tempo, Swing function
- Step Sequencer (16 steps/32 steps)
- Song function (Maximum 300-bar)
- Tone editing (Name, Volume, Panning, Mute Group, Tune, Dynamic Processor, Wave Trimming, Attack/Decay Time)
- Audio Import (AudioCopy, iPod Library, File)
- Audio Export
- Real-time recording
- Various Master Effects (Distortion, Dynamic Processor, Delay, Reverb)
- Control in real time, assigning the effect parameters to the FX XY Pad
- Real-time Effects (Slicer, LPF, Glitch, and Roller)
- WIST (Wireless Sync-Start Technology) is supported
- Audiobus (Input) is supported
- CoreMIDI (Input) is supported
- AudioCopy/Paste is supported
- Playing in the background is supported

S4 Rhythm Composer Pro is a dedicated iPad app. Not available on iPhone or iPod Touch.