# Spectrum Synthesizer Bundle — 4 Pro Instruments, 30+ Modes!

> Bundle of 4 pro Audio Unit synthesizers and 1 effect for music production. (iPhone/iPad app by Thomas Burns.)

- Source: https://appshunter.io/ios/app/spectrum-synthesizer-bundle/id1467384251 (this page in markdown: same URL + `.md`)
- Developer: [Thomas Burns](https://appshunter.io/developer/522224284)
- Category: Music
- Price: Free
- Rating: 4.80/5 from 135 App Store ratings · 53 written reviews indexed
- Age rating: 4+
- Requires: iOS 11.0 · 13 MB
- Languages: American English
- Released: 2019-07-06
- Data updated: 2026-08-30
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/spectrum-synthesizer-bundle/id1467384251/reviews.md

## What is Spectrum Synthesizer Bundle?

Spectrum is a collection of 3 Audio Unit synthesizers and one Audio Unit effect.

Spectrum is based on popular eurorack synthesizer modules made by Mutable Instruments.

Included are four audio units:

Spectrum - Multi-mode 8-voice polyphonic oscillator featuring 14 high quality oscillator algorithms.  Supports MPE.

Modal - Modal synthesis.  Bowed, Blowed, and Struck sounds through a 64-band resonator.  Also included as an effect.

Resonator - 7 beautiful string generation algorithms.  Also included as an effect

Granular - Granular sampler, looper, pitch shifter, reverb effect.  Note that Granular is an Audio Unit effect, not an instrument, so it goes in an effect slot.

To use Spectrum, load the Audio Units in your DAW or AU host of choice, like Audiobus, GarageBand or AUM.

Each audiounit also features:
- modulation LFO featuring tempo sync, key reset, reset phase adjustment
- modulation ADSR envelope
- XY touchpad (except on Modal)
- 2-source modulation matrix allowing for complex and evolving patches.
- MIDI CC control of parameters
- Resonator and Modal are also loadable as an AudioUnit effect

Spectrum contains DSP code provided under the MIT open source license by Mutable Instruments.

## Key features

- Multi-mode polyphonic oscillator
- Modal synthesis
- String generation algorithms
- Granular sampler and looper
- Modulation LFO and ADSR envelope
- XY touchpad and modulation matrix

## Recent user reviews (10 of 53)

All indexed reviews: https://appshunter.io/ios/app/spectrum-synthesizer-bundle/id1467384251/reviews.md

### 5/5 — Fantastic apps

*2026-08-07*

Love playing these with the arp on my midi keyboard. Beautiful, refreshing and resonant.

### 4/5 — Don’t sleep on this one.

*2026-07-08*

Deep and capable of a lot of crazy modulation, has a distinct character all its own and excels at unique, fluid, flowing soundbeds.

Only caveat: crashes more than it should.

### 5/5 — Don’t sleep on this one.

*2025-12-05, version 0.7*

Deep and capable of a lot of crazy modulation, has a distinct character all its own and excels at unique, fluid, flowing soundbeds.

### 5/5 — Great plugins

*2025-08-09*

GarageBand doesn’t show the button to open the GUI of the plug-in. The few presets sound awesome though, and I hope this will get better.
Edit: somehow I only used the „open UI in fullscreen“ button until recently, which was not available. Opening the parameters worked. I love this synth!

### 5/5 — Sounds Incredible, super lite, absolute beast AU’s

*2025-02-20*

Just incredible.  I use it all the time- so versatile, lite and just an absolute sonic gem.    I’ve never heard anything negative about the Spectrum bundle.    The creator also has this eurorack synth cheat sheet that is also extremely useful.

If you don’t like it, simply delete it.
However, if you love it (most likely). Please consider showing some love with an honest review.     

I appreciate Thomas Burns contribution to my musical betterment and the accessibility to all.      Fantastic stuff

### 5/5 — Sounds Incredible, super lite, absolute beast AU’s

*2025-02-06*

Just incredible

### 5/5 — Awesome free synths!

*2024-02-07*

These synths are based off of mutable instrument modules and they sound great! You can get some real interesting sounds out of these things! Thanks to the developer!

### 5/5 — Great app but description misleading!!

*2023-04-09*

Hello developer ! I love this app however there is no granular synth ???? The description includes the granular synth however upon purchase , it is missing ! I suggest bring back granular or take it out of description thank you .

### 5/5 — Amazing

*2022-07-01*

It is everything I was looking for! The sounds that come out of this are heavenly and the fact that it’s all totally free is just unbelievably kind of the creator. Only problem is that the modal synthesizer doesn’t work on its own!

### 1/5 — Works great on iOS, not on macOS

*2022-04-28, version 0.7*

On macOS, creates massive feedback. I caution you not to download it for desktop use.

## Frequently asked questions about Spectrum Synthesizer Bundle

### What is Spectrum Synthesizer Bundle?

Spectrum Synthesizer Bundle is a collection of four professional Audio Unit (AU) synthesizers and one AU effect. These instruments are inspired by popular eurorack synthesizer modules and offer a wide range of sound design capabilities for music production.

### What are the main instruments included in the bundle?

The bundle includes four main audio units: Spectrum (a multi-mode 8-voice polyphonic oscillator), Modal (for modal synthesis), Resonator (for string generation), and Granular (a granular sampler and effect). Modal and Resonator can also be loaded as effects.

### How much does Spectrum Synthesizer Bundle cost?

The provided information indicates that this application is a paid product and does not have in-app purchases or ads. The exact price would typically be found on the app store listing.

### What devices and software are compatible with Spectrum Synthesizer Bundle?

This application is designed to be used as Audio Units within a Digital Audio Workstation (DAW) or an AU host application. Examples of compatible hosts include Audiobus, GarageBand, and AUM on compatible devices.

### What are some common use cases for this app?

Users can employ this bundle for creating diverse electronic music genres, designing unique soundscapes, generating experimental audio textures, and adding complex modulation to their tracks. It's ideal for producers seeking advanced synthesis and effects within their existing music production workflow.

## Version history (last 5 releases)

### 0.7 — 2021-08-02

Fixes song rendering in Garageband and crashes in other DAWs.  Double-tap control knob to type in a specific value.  Double tap label to reset value.

### 0.66 — 2020-01-16

Bug fixes: iPhone users can close popup menus, fixed crash when resizing AU window on 3x pixel density devices.

### 0.65 — 2020-01-10

UI improvements.  Tap the value of a menu picker to pick from a scrollable menu.  Added "quality" setting to Granular - set to low quality for longer 8-second delay buffer.  Note that portrait support has been removed for better consistency across devices and sizes.

### 0.6 — 2019-10-15

MPE Support!  Route Velocity, Aftertouch, Slide, Lift in the modulation matrix.  Added dedicated "Velocity depth" knob to apply MIDI velocity to note amplitude.  Set default pitch for resonator / modal effect to 48 if no MIDI notes are sent.  Settings tab can be saved as default / auto-loaded on new instances.  Support for Sustain pedals.  Parameter grouping cleaned up.

### 0.5 — 2019-08-27

Fixes errors in MIDI CC mapping introduced in 0.4.

## Apps similar to Spectrum Synthesizer Bundle

| App | Rating | Price | Category |
| --- | --- | --- | --- |
| [Spectrum Analyzer: Spectrogram](https://appshunter.io/ios/app/spectrum-analyzer-spectrogram/id981810895) | 4.2 (195) | Free | Music |
| [Sound Editor: Audio Changer](https://appshunter.io/ios/app/sound-editor-audio-changer/id1325953979) | 3.1 (768) | Free | Music |
| [MicSwap MultiTrack: Mic Studio](https://appshunter.io/ios/app/micswap-multitrack-mic-studio/id1538031783) | 4.6 (1,052) | Free | Music |
| [Audiobus: Mixer for Music Apps](https://appshunter.io/ios/app/audiobus-mixer-for-music-apps/id1129130361) | 4.5 (594) | Free | Music |
| [MicSwap: Microphone Recording](https://appshunter.io/ios/app/micswap-microphone-recording/id895157889) | 4.5 (6,836) | Free | Music |
| [SoundLab - Audio Editor](https://appshunter.io/ios/app/soundlab-audio-editor/id1450417400) | 4.6 (14,291) | Free | Music |

## More apps by Thomas Burns

- [Synth Modes](https://appshunter.io/ios/app/synth-modes/id1445358435)

All apps by Thomas Burns: https://appshunter.io/developer/522224284

## Related topics

[synthesis connect](https://appshunter.io/ios/topics/synthesis-connect) · [dxi fm synthesizer](https://appshunter.io/ios/topics/dxi-fm-synthesizer) · [mighty synth sampler](https://appshunter.io/ios/topics/mighty-synth-sampler) · [hilda synthesizer](https://appshunter.io/ios/topics/hilda-synthesizer) · [synthesis forum 2025](https://appshunter.io/ios/topics/synthesis-forum-2025)

---

*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 2026-08-30.*