# Quantum Sequencer — multitrack midi step sequencer

> Interactive MIDI step sequencer for experimental music composition and performance. (iPhone/iPad app by anthony saunders.)

- Source: https://appshunter.io/ios/app/quantum-sequencer/id1207932898 (this page in markdown: same URL + `.md`)
- Developer: [anthony saunders](https://appshunter.io/developer/460303742)
- Category: Music, Education
- Price: $7.99
- Rating: 4.60/5 from 35 App Store ratings · 32 written reviews indexed
- Age rating: 4+
- Requires: iOS 12.0 · 191 MB
- Languages: American English, Chinese (Simplified, China)
- Released: 2017-10-06
- Data updated: 2026-08-21
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/quantum-sequencer/id1207932898/reviews.md

## What is Quantum Sequencer?

Quantum is a performance midi sequencer which approaches music composition with an interactive creation processes - sometimes referred to as 'noodling'.

Where pattern or piano-role sequencers are good for music forms (intro/verse/chorus etc) or grid entry, Quantum's approach is built around the idea of a step being the focus - think of the step as a single note or chord written on a music sheet then add a lot of extra notation (like probability of playing or ornamentation say). 

These highly detailed steps are then aligned into sequences (think melodies) that loop. You can have any length up to 64, but these can be further split into 4 sub-sequences that have their own set of sequencer parameters (like tempo, play direction, transpose etc).

To enter step parameters such as note pitch, velocity, gated length etc, 16 general faders are available which allow you to draw, drag, select copy/paste, inc/dec & link together to edit values. These are also midi learnable (midi cc or nrpn) to allow you to use control surfaces or midi controllers.

To aid you with faster control Quantum has loop actions which you can program in to carry out tasks when a sequence loops - e.g. transpose, randomise, start or load another sequence etc.

With up to 24 sequences playing Quantum introduces a mixer page allowing you to blend midi velocities. Built on the MidiSequencer engine, midi FX, devices & Controllers are now possible per sequence.

So why would Quantum be good for your setup? There are many midi enabled IOS & hardware synths that produce exotic timbres if you send them fast & varied midi controls that you just would not hear with keyboard playing or slow tempo tunes. Also, Quantum, embraces experimentation in melody creation and by copy/pasting allowing quick setup of arpeggios & counterpoint tunes that you can create & manipulate on the fly!

note : This app sends midi information - you need to use it in conjunction with any midi enabled iOS synth app (e.g. Sunrizer) to hear sounds

## Key features

- Interactive step-focused composition
- Detailed step notation (probability, ornamentation)
- Configurable sequence lengths and sub-sequences
- 16 general faders for parameter editing
- MIDI learnable faders
- Programmable loop actions
- Per-sequence MIDI FX, devices, and controllers

## Recent user reviews (10 of 32)

All indexed reviews: https://appshunter.io/ios/app/quantum-sequencer/id1207932898/reviews.md

### 2/5 — No AUV3, forget it

*2026-04-27*

This might have been good if they’d updated it to an AUV3 but unfortunately without that functionality it’s just a very dated looking UI with limited application.

### 3/5 — Useful for multipart compositions

*2023-05-19*

Update May 2023

Can you please answer this question.

QUESTION: How can we sustain a note instead of playing note to note.

I’ve sent emails and asked over a year ago.

Now your email doesn’t work.

========
I think this is a fantastic app for compositions. I can’t figure out, though, how to sustain a note. Is this possible? If not, can you add this feature.

**Developer response:** Each step can have a duration (gate) of up to 400% of a step length - you can use that to create sustained notes.

### 1/5 — Funktioniert nicht

*2023-01-23*

Keiner meiner Synths Nave, iMini und Nave liess sich über den Quantum ansteuern. Ich hab an den Synths und Quantum alle möglichen Einstellungen ausprobiert. Nichts war zu hören!

**Developer response:** Please contact me so I can help you with your setup. There is an email for support in the app.

### 5/5 — More than a traditional step sequencer

*2023-01-15*

I haven’t found an end to what this can do

**Developer response:** Thank you for your review. Glad you are enjoying sequencing

### 5/5 — Very complex..but ultimately brilliant

*2022-07-22*

Update to my first review……I set Quantum up as described in my previous review, I removed all synths, then launched iM1 in track 1 and made sure it was set to Multi mode (inside the app), then pressed Play in Cubasis3 and WOW….notes and drums flying around everywhere, it sounded like a full orchestra practicing because I never expected to hear all the sequencer parts playing at the same time.  The 8 part multitimbral iM1 is the perfect companion to Quantum Sequencer, now all 6 sequencer parts CAN be heard at the same time, it’s just fantastic, well…..it will be once I set the sequences to harmonise with each other.
Worthy of ⭐️⭐️⭐️⭐️⭐️⭐️⭐️⭐️⭐️⭐️

Wed 20 July.
I have just purchased Quantum, I primarily wanted to use It in Cubasis3, and already I have spent what seemed like hours trying to get a sound out of it, all was lost until I opened Audiobus 3 and selected Quantum as Audio, then set Cubasis3 as out….success, but when I set up 3 synths in Cubasis, then create 3 separate step sequences in Q, only one of the 3 synths selected can be heard at a time!
A very complex and mind boggling app, and no doubt incredibly brilliant, definitely need to read the manual with this one though.

**Developer response:** Thank you for your review - I'm glad you find this app creative

### 5/5 — Amazing but struggling with a couple of things

*2022-04-29*

This review is just a rough recording of my experience with the apps, devices or combination(s) of devices & apps mentioned, made mostly without any technical knowledge of them.

It would seem that because the QUANTUM iOS MIDI sequencer does not by itself emit audio and therefore does not advertise itself as an audio source to the AUDIOBUS device (AU or APP) list, it is not detectable (or not recognized OR BOTH) BY AUDIOBUS as an audio source and where AUDIOBUS only makes the device currently generating the i/o data of a sequence rather than its audio emitting recipient (MIDI slave synthesizer etc.) available as an audio source it is impossible to route audio from instruments sequenced with QUANTUM iOS MIDI sequencer to recording, looping, sampling apps or built-in sound library recorders (AudioShare, AudioCopy, Flip, AUM, GarageBand, Xequence) WITH AUDIOBUS internally in iOS. This is of course a non-issue if you plan to work with external devices to record, sample or just amplify audio generated by instruments sequenced with QUANTUM iOS MIDI sequencer.

Independent of this, Quantum is AMAZING. The device has far more options, features and flexibility than I MYSELF will ever need in an iOS device, but it would be idiotic to cite that as a negative! Especially fun for note by note, parameter-locking or “vertical,” tracker-style sequencing. Well worth the investment of time and revenue but I would recommend primarily as an iPad app. In fact, evaluate it using an iPad before passing final judgment.

🥹📻💪🏽💪🏼💪🏻😮‍💨👂🧠🙄📡😠🕹🤔🤯😫⌚️⌚️⌚️🤩🤩🤩🥳🥳🥳

### 1/5 — Funktioniert nicht, iPad Air IOS 15

*2022-01-24*

Der Sequencer läuft zwar aber die Gate-Länge aller Noten ist null. Auf Note-on folgt sofort Note-off, das bedeutet, dass kein Ton gespielt wird. Mit Midi-Monitor überprüft.

### 3/5 — Problems with velocity send Signals

*2021-08-13*

Sing the App to Control Software Synth on the IPad Workshop Great. But when sending MIDI to My Hardware Synth (Novation Peak) or Software Synth on my Mac (Arturia V Collection) the differences in velocity are not transported. The notes are equally loud or muted. I would have liked to ask this question by email but there is no possibility on the developers Web Site and I don`t wann to establish a Facebook Account to do so. So would you please answer how to solve this. 
Thanks

### 5/5 — It”s not monotonous!

*2020-12-31, version 1.13*

This is my favourite iOS sequencer.   It will run all my iOS synths and also hardware synths.   It is comprehensive and a little bit of time spent on YouTube (The developers own channel or The Sound Test Rooms tutorial) and with the manual are worth it.  It is a step sequencer, not a piano roll.   I love it and I have purchased a few others over the years, but always come back to Quantum.   I learn something new, every time I do.

### 5/5 — Very Deep

*2020-04-14*

This is one where you need to read the Manual. (Very well written). 

I learned the hard way! Purchased it, tried it, got frustrated and pushed it to one side. 

Thanks to this prolonged lockdown - I dusted off some of my - pushed aside apps and took a second look. Well worth it - this one is a gem.

There are a few ‘look see’ Videos on YouTube but nothing will beat hands on - keep it simple at first Just Quantum and you favourite Synth on the desktop no need to use a DAW - But works equally as well in one.

This app goes way beyond your standard sequencer. Way way beyond.

## Frequently asked questions about Quantum Sequencer

### What does Quantum Sequencer do?

Quantum Sequencer is a performance MIDI sequencer that focuses on an interactive approach to music composition. It allows users to create detailed musical steps, arrange them into looping sequences, and manipulate parameters in real-time for experimental music creation.

### What are the key features of Quantum Sequencer?

Key features include a step-focused composition method with detailed notation options, configurable sequence lengths and sub-sequences, 16 faders for parameter editing with MIDI learn capabilities, programmable loop actions, and per-sequence MIDI FX and controller support.

### How much does Quantum Sequencer cost?

Based on the provided information, Quantum Sequencer is a paid application. There are no mentions of in-app purchases or advertisements, indicating a one-time purchase model.

### What devices is Quantum Sequencer compatible with?

The application is designed for iOS devices and sends MIDI information. It requires use in conjunction with any MIDI-enabled iOS synth app or hardware to produce sound.

### What are common use cases for Quantum Sequencer?

Common use cases include experimental melody creation, generating complex arpeggios and counterpoint tunes, and creating varied MIDI controls for exotic synth timbres. It's ideal for live performance and on-the-fly manipulation of musical ideas.

## Version history (last 5 releases)

### 1.18 — 2022-12-07

fix for some iPhone/iPad screen layouts

### 1.17 — 2022-04-29

Added Bluetooth privacy fix
Latest Audiobus library
Record button pop-up text

### 1.16 — 2022-02-10

bug fix for midi export

### 1.15 — 2022-01-31

Updated link to pdf manual & email for support

### 1.14 — 2021-05-27

Updated for latest IOS device screen layouts & IOS 14
Latest Midibus, Audiobus & Ableton Link libraries
Midi In Prog Chg now loads selected sequence version (delayed if cycle on) - eg $C0 02 loads version 2
Device input panels allow blocking of Prog Chg messages

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## More apps by anthony saunders

- [midiSequencer](https://appshunter.io/ios/app/midisequencer/id787934896)
- [Midi Echo AU](https://appshunter.io/ios/app/midi-echo-au/id1422324067)
- [Polythemus AU](https://appshunter.io/ios/app/polythemus-au/id1439815017)
- [Photon AU](https://appshunter.io/ios/app/photon-au/id1441542979)
- [Skirmish 1944](https://appshunter.io/ios/app/skirmish-1944/id1597985916)

All apps by anthony saunders: https://appshunter.io/developer/460303742

## Related topics

[midify](https://appshunter.io/ios/topics/midify)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-21.*