--- title: "In Theory - Interval Keyboard — App Overview" url: https://marlvel.ai/apps/in-theory-interval-keyboard category: Music developer: Cem Olcay platforms: ios rating: 5.0 (4 ratings) pricing: paid report_level: overview generated: 2026-04-30 last_verified: "2026-04-30T10:06:23.444Z" --- > **Key Insight:** In Theory provides a unique, interval-centric approach to MIDI input that simplifies the creation of complex scales and chord voicings. | Metric | Value | |--------|-------| | Category | Music | | Rating | 5.0 ★ (4) | | Pricing | paid | | Platforms | iOS | | Latest Version (iOS) | 2.2 | | Developer | Cem Olcay | ## What is In Theory - Interval Keyboard? In Theory is a MIDI keyboard application designed for interval-based music composition, offering access to over 110 scales. It allows users to manipulate notes via a keypad interface or external MIDI hardware to generate complex chord voicings and extended harmonies. ## Key Features - **Interval-Based Keypad**: A bottom-row interface allows users to shift notes relative to the current scale using interval buttons ranging from -2 to +2. - **Chord Voicing Controls**: Users can toggle additional scale intervals and select notes from adjacent octaves to build rich, extended chords. - **MIDI Integration**: Supports external MIDI keyboard input, mapping white keys to interval triggers and allowing MIDI CC messages to toggle chord intervals. ## Who is it for? Musicians and producers looking for an interval-based workflow to experiment with scales and chord structures. ## Links - [App Store](https://apps.apple.com/us/app/in-theory-interval-keyboard/id1667984658?uo=4) - [Full Intelligence Report](https://marlvel.ai/apps/in-theory-interval-keyboard) --- *This is an overview report. Sentiment analysis, competitive landscape, and SWOT analysis are available in the [full intelligence report](https://marlvel.ai/apps/in-theory-interval-keyboard).* *Generated by [Marlvel.ai](https://marlvel.ai) — Independent app intelligence.*