Hi all,
I just released the public TestFlight beta of M2DX, a DX7-compatible FM synthesizer for iOS/iPadOS 18+. Built in Swift 6, with
the synthesis core being a direct port of the msfa/Dexed engine using Int32 Q24 fixed-point arithmetic.
TestFlight + full feature list: https://hakaru.net/M2DX-support/
Source: https://github.com/hakaru/M2DX
What it does:
- Full DX7 algorithm set: 6 operators × 32 algorithms
- 32 factory presets (BRASS1, E.PIANO1, WOOD BASS, FLUTE 1, etc.)
- Bit-accurate Yamaha OPS chip emulation
- 16-voice polyphony, sustain pedal (CC64), ±2 semitone pitch bend
- 6-stage FX chain (EQ → Drive → Chorus → Reverb → Stereo → Maximizer), every param MIDI Learn-mappable
The MIDI 2.0 angle:
- Full UMP support: 16-bit velocity, 32-bit CC, 32-bit pitch bend
- Automatic MIDI 1.0 fallback (works with any traditional MIDI gear)
- MIDI-CI Property Exchange: 155+ parameters auto-discoverable, JSON-based preset management (no SysEx required)
- Low-latency AVAudioSourceNode direct rendering inside the CoreAudio render callback
Honest disclosure - not yet at instrument-grade quality. I'm releasing the public beta specifically to gather feedback.
Particular gaps:
- MIDI 2.0 hardware compatibility (I don't own enough devices to test broadly)
- DX7 preset 1:1 parity vs original DX7 / Dexed
- SysEx patch import compatibility
- FX chain musical tuning (still rough)
- Vendor-specific MIDI 2.0 extensions (KORG partially analyzed)
Currently standalone iOS / iPadOS app. macOS planned. AUv3 under consideration.
Happy to discuss the FM engine port (msfa → Swift) or MIDI 2.0 implementation in detail.
M2DX [iOS, TestFlight beta] – DX7-compatible FM synth with full MIDI 2.0 UMP support
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- KVRer
- 7 posts since 30 Mar, 2026
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- KVRAF
- 9547 posts since 6 Jan, 2017 from Outer Space
Thanks, will it also run on MacOS? I don’t know if I could Testflight it there as well. I have Bidule which loads AUv3 and exposes it to Bitwig…
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- KVRer
- Topic Starter
- 7 posts since 30 Mar, 2026
Great question! A few things to clarify:
**macOS:**
Currently iOS/iPadOS 18+ only. macOS support is on the roadmap, but the
TestFlight link won't work on Mac at this stage — I'll post here when
that changes.
**AUv3 + Bidule/Bitwig:**
Not yet, unfortunately. M2DX is Standalone only for now. The AUv3 port is
planned, but MIDI 2.0 UMP handling on macOS has some rough edges I want to
get right before shipping it — I'd rather delay than break the 32-bit CC /
pitch bend resolution that makes MIDI 2.0 worth using in the first place.
The Bidule → Bitwig chain is exactly the kind of setup I'm targeting, so
this is useful signal. I'll update this thread when AUv3 is available.
**macOS:**
Currently iOS/iPadOS 18+ only. macOS support is on the roadmap, but the
TestFlight link won't work on Mac at this stage — I'll post here when
that changes.
**AUv3 + Bidule/Bitwig:**
Not yet, unfortunately. M2DX is Standalone only for now. The AUv3 port is
planned, but MIDI 2.0 UMP handling on macOS has some rough edges I want to
get right before shipping it — I'd rather delay than break the 32-bit CC /
pitch bend resolution that makes MIDI 2.0 worth using in the first place.
The Bidule → Bitwig chain is exactly the kind of setup I'm targeting, so
this is useful signal. I'll update this thread when AUv3 is available.
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- KVRer
- Topic Starter
- 7 posts since 30 Mar, 2026
**Update: M2DX is now on the App Store — free, and it ships with an AUv3 plug-in**
Quick follow-up to this thread. M2DX is out of TestFlight and live on the App Store as of this week, still free:
https://apps.apple.com/app/m2dx/id6763840208
Two things that came up earlier in the thread are now done:
- **AUv3 plug-in.** Earlier I said it was standalone-only — that's changed. M2DX now runs as an AUv3 instrument inside GarageBand, AUM, Logic Pro, and other AUv3 hosts, alongside the standalone app.
- **Beyond iPhone.** It also runs on Apple Silicon Macs and Vision Pro via the iOS app.
Still the same engine: 6-operator / 32-algorithm FM, bit-accurate OPS-style emulation, native MIDI 2.0 UMP (16-bit velocity, 32-bit controllers/pitch bend), a 6-stage FX chain, MIDI Learn, and you can bring your own DX7-format .syx banks.
The DX7-compatible engine (M2DX-Core) is still open source (Pure Swift, Apache-2.0): https://github.com/hakaru/M2DX-Core
Feedback and bug reports very welcome — especially on the AUv3 side in different hosts.
Quick follow-up to this thread. M2DX is out of TestFlight and live on the App Store as of this week, still free:
https://apps.apple.com/app/m2dx/id6763840208
Two things that came up earlier in the thread are now done:
- **AUv3 plug-in.** Earlier I said it was standalone-only — that's changed. M2DX now runs as an AUv3 instrument inside GarageBand, AUM, Logic Pro, and other AUv3 hosts, alongside the standalone app.
- **Beyond iPhone.** It also runs on Apple Silicon Macs and Vision Pro via the iOS app.
Still the same engine: 6-operator / 32-algorithm FM, bit-accurate OPS-style emulation, native MIDI 2.0 UMP (16-bit velocity, 32-bit controllers/pitch bend), a 6-stage FX chain, MIDI Learn, and you can bring your own DX7-format .syx banks.
The DX7-compatible engine (M2DX-Core) is still open source (Pure Swift, Apache-2.0): https://github.com/hakaru/M2DX-Core
Feedback and bug reports very welcome — especially on the AUv3 side in different hosts.