Sinusoid is a tracker/sequencer sound machine designed for the iPhone, drawing inspiration from retro 8-bit game consoles. It features 3 sound channels for tones and 1 channel for drums and noise. The app offers a wide range of audio parameters including pan, amplitude envelope, vibrato, pitch glide, resonant filter, and a second oscillator for ring modulation and FM synthesis. Users can further enhance their sounds with features like an arpeggiator, delay, and bit crusher. Sinusoid allows exporting songs to AIFF format for playback within the app or sharing with other applications. MIDI support enables control over parameters, note input, and integration with other synths through various MIDI protocols like Core MIDI, Bluetooth, IAA MIDI, and AUv3 MIDI. Seamless connectivity with other sound apps is facilitated through Audiobus, Inter-App Audio, or AUv3.

The app offers a comprehensive set of features, including multiple tone channels with various waveforms, stereo panning, customizable amplitude envelopes, and the ability to override audio parameters on a per-note basis. Users can easily collaborate and share projects across devices on the same network, export projects to AIFF format, and leverage MIDI capabilities for versatile control and integration. Sinusoid provides a robust platform for music creation and experimentation, with support for popular MIDI protocols, flexible connectivity options, and a user-friendly interface.