King of FM 1.9 Update: Free FM Synth Adds Microtonality for iOS/macOS
King of FM is a free FM synthesizer plugin for iOS and macOS developed by AudioKit. The new update 1.9 adds extensive microtonality support, custom scale import, and improved workflow features, making it a stronger choice for producers seeking DX7-style FM synthesis with modern flexibility.
What’s new in version 1.9
The update introduces a dedicated microtonality section with over 150 curated microtonal scales, including North Indian, Hexanies, Arabic Egyptian, and Eastern scales. Users can also import custom scales via .scl tuning files for full tuning flexibility. A new Western key-locking function allows arpeggiators, sequencers, or external MIDI to retain the correct key when switching presets. Presets can now store scale and key information, and scales can be locked independently of presets for live performance use.
Additional improvements include AUv3 state saving for tuning and scale settings, program change MIDI mappings, and general under-the-hood optimizations. The update is free for existing users and maintains the plugin’s standalone and AUv3 compatibility on iPhone, iPad, and macOS.
Who is King of FM for
The synth targets producers and performers who want accessible, high-quality FM synthesis without cost barriers. Its 300+ ready-to-use presets draw from classic FM synths like the DX7 and TX81z, offering immediate inspiration for electronic, ambient, and experimental productions. The microtonality update broadens its appeal to musicians working with non-Western tunings or custom intonation systems.
Availability and system requirements
King of FM is available as a free download for iOS and macOS, functioning as a standalone app and AUv3 plugin. The update to version 1.9 is free for all existing users. For new users, the app can be downloaded from the App Store.
The update enhances both creative workflow and live performance potential, solidifying King of FM as a versatile and cost-effective FM synth option in the iOS/macOS ecosystem.
FAQ
Does the microtonality update require a paid upgrade? No, the microtonality features and all of update 1.9 are included as a free update for existing users.
Can I import my own tuning scales into King of FM? Yes, the update supports importing custom scales via .scl tuning files.
Is King of FM available on macOS? Yes, it runs as a standalone app and AUv3 plugin on macOS, iPhone, and iPad.