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Use as/for:
- Sound design
- Experimental musical instrument
- Fun
- An alternative to pre-recorded music.

Key Features:
- Fast and lightweight
- Four tracks
- Loads sound files of up to seven minutes length in any audio format
- Among other effects contains a zero latency Convolution Reverb (supports Impulse Responses of up to 10 seconds length.)
- Filterbank based Vocoder
- Time Stretching, Phase Vocoder FXs
- Realtime Crossynthesis
- Can be used for Overdubs (Allows mic recording while playing back sampled sounds)

First use instructions:
1. Press POWER. Upper right power button turns on audio engine which is TURNED OFF on startup to save battery.
2. Press EJECT. Load a sound file.
3. Press PLAY.

Further instructions in the menu.

Recommended device specifications:
- 2GB+ RAM
- Android 8.1+
Not recommended for low end devices.

Google Play Store Category:

Primary: Applications

Secondary: Music & Audio

Google Play

Privacy Policy

Total Ratings



Grainstorm screenshot 1Grainstorm screenshot 2Grainstorm screenshot 3Grainstorm screenshot 4Grainstorm screenshot 5Grainstorm screenshot 6Grainstorm screenshot 7Grainstorm screenshot 8

Version History

Launched Mar 31, 2014 (almost 6 years ago).

Releasing new versions every about 1 month, on average.

Feb 22
Version 1.6.12


Jan 10
Version 1.6.11


Dec 17
Version 1.6.10


Nov 05
Version 1.6.9


Oct 13
Version 1.6.8

Please see Changelog inside the app's menu.

Sep 19
Version 1.6.7

Please see Changelog from the App's Menu.

Jul 01
Version 1.6.6

Please see Changelog from the App's Menu.

Jun 19
Version 1.6.5

- Corrected releasetime control of envelope followers.
- Corrected semitones as LFO target.
- Computationally less demanding and more stable filters of the filterbank based Vocoder.
Pro Version:
- PVAmps
- Reverb 5

May 28
Version 1.6.4

- Multitouch support
- Sidechain compression

Apr 30
Version 1.6.3

Pro version: LFO sync with external MIDI clock

Apr 28
Version 1.6.2

Pro version: LFO sync with external MIDI clock

Mar 19
Version 1.6.1

- LFO Waveform Editor
- Mp3 Recording
- Enhanced LFO range adjustment
- MIDI Support
- 64-bit Support
- Convolution based reverb

Feb 04
Version 1.5.2

- Enhanced LFO range adjustment
- MIDI Support
- 64-bit Support
- Convolution based reverb

Jan 25
Version 1.5.1

- Midi support

Jan 16
Version 1.5.0

- 64bit support
- Usage of AAudio on Android 8.1+
- etc.

Dec 27
Version 1.4.13

- Convolution based reverb
- Bypass switch for all effects
- etc.

Oct 16
Version 1.4.12

- minor fixes

Sep 16
Version 1.4.11

- Multithreaded, faster Cross Synthesis computation, revised outputlevels
- Revised loop and LFO Controls, new LFO destinations
- Bug fixed when switching from Mono to Stereo or changing buffersize on some devices the change would not be applied after restarting the device.
- More, smaller things...
EDIT: Recently introduced rare crash on startup fixed.

Jun 09
Version 1.4.10

- GUI changes/cleanups
- Switchable new internal / external filebrowser
- Recording presets

Pro Version:
- Selectable output folder
- Optionally asks for recording filename

May 21
Version 1.4.9

See "Recent Changes" in the app menu.

Mar 30
Version 1.4.7

See "Recent Changes" in the app menu.

Feb 26
Version 1.4.5

- In app billing for the pro version
- No more support for pre Android 4.4 (Sorry, but too many issues.)
- New Compressor (which, we believe, is a nice one)
Pro Version:
- Stereo version of the new compressor
- Multi Delay
EDIT: Again a quick fix for overlapping buttons on devices with software emulated control buttons.

Jan 28
Version 1.4.4

- A vocoder algorithm in the cross synthesis section
- Automatic limiting of the final mix
- Bugfix concerning setting of wrong LFO destinations

Jan 12
Version 1.4.3

- Stereo effects are queued
- Two fractional stereo crossfeedback delays
- Crash fixed when fft active in stereo mode
- Revised phaser, flanger, chorus and reverbs
EDIT: - Exporting loops would record blank wav. Fixed.
- Revised rotary controls.
- Short double click on controls now invokes an input field.

Jan 04
Version 1.4.2

- More Effects. Among others: a grain by grain ringmodulator and a delay with cubic interpolation, filters and delay time controllable by lfo. The last one requires paid version.
- Effects are now appended to the fx queue when activated instead of having a fixed position.
EDIT: - The decoder still caused crashes on startup on some older devices with Android prior to 5.0 as its library won't load. Recompiled. Hopefully fixed. Sorry for the inconvenience.
- Density as lfo destination

Dec 16
Version 1.4.1

- Stereo mode
- Improved performance on multicore cpus
- Revised reverbs
- Several minor bugfixes
- Recompiled decoder with less aggressive optimizations because it caused some crashes on old devices
- Changed lifecycle behaviour. Removed screen always on flag.
- One effect did not power on since the last update. Fixed.
- Fixed new loop behaviour for locked tracks.
- Fixed lfo phase inaccurateness when controlling grain parameters at high rates.

Nov 19
Version 1.4.0

- Improved sound quality and faster decoding of almost any audio format. Should not crash any more on certain audio files.
- Redesign of the gui rendering mechanism resulting in a vastly reduced overall memory usage.
- Added 5 nice sounding stereo effects (4 Reverbs and a Chorus) and 4 nice sounding mono effects (Phaser, Flanger, Pitch Shifter and Echo). Requires Unlocker.
EDIT: Fixed a crash when loading sound files without channel layout information.

Oct 28
Version 1.3.4

- Saving and importing of presets (requires the paid version.)
- New theme
- New icons
- A menu from where instructions can be read and which gives the option to change the audio buffer size
- Lots of fine tuning
*edit* possible crash fixed when importing a preset / crash fixed when denying requested permissions on startup

Oct 09
Version 1.3.3

- Added a bandreject filer.
- Updated Low/Highpass filter.
- Updated Distortion. (Added an optional resonant prefilter which is based on the Karplus/Strong Algorithm. Experimental).
- Fixed a crash when trying to access files or directories without read/execute permissions from within the filebrowser.
EDIT: Switched back to normal rendering due to too many problems on certain devices.

Sep 14
Version 1.3.1

41: - Fixed LFOs
- Bufferreset when phase correction gets activated. To avoid eventual feedback.

Apr 30
Version 1.3

37: -fixed some issues on Android 7+
- fixed a possible crash on shutdown
36: - LFOs
- enhanced control over grainshape
- a kind of manual added
- optional virtual memory use
- speed optimizations
- revised filter and filter white
- revised compressor

Feb 20
Version 1.2

- "Unphasinesser" now works with all playback speeds, fixed a bug when active together with other effects. Now works well.
- fixed the db-meter
- fixed text display problems on some devices
- added x86 support

Nov 04
Version 1.1


May 25
Version 1.0

Realtime Granular Synthesis for Android.
Grainstorm takes sound data as input, granulates it and pushes it back to audio out in realtime.
Input either comes from recordings over the internal mic or from audio files which the user can choose from disk and are decoded afterwards. Currently only .mp3 and .flac stereo formats are supported, the samplerate of the input has to match the samplerate of the device (which is determined automatically and is 44.1kHz in most cases) or the result will be time-stretched or time-shrinked respectively and the input file must not exceed a length of 7 minutes.
There is a cursor which can be moved over the waveform to determine the exact position from where input is taken. The waveform can be zoomed in until one sampleframe per pixel is displayed. Thus the cursor can be moved as exactly as one sample if required.
The two other cursors determine start and stop position of playback. In combination with playbackspeed and the other parameters evolving sound textures, morphing over a short or long period like hours can be created.
Interesting results - always depending on what you take as input - which could be used for electronic music production can be achieved if input comes from sampled voices or synthesized sounds samples.

Output can be recorded by pressing the record button. On the second press the recording is automatically saved in .wav format in the user's music folder.

Grainstorm performs pretty well on recent devices with multi-core CPUs. The DSP-part which is highly optimized and most of the GUI-part are written in C - interaction between both is fast.

Before downloading the unlocker you should make sure that Grainstorm works satisfyingly on your device. It is not recommended for "slow" devices. If you encounter clipping turn out all background services. If you still encounter clipping, then Grainstorm might not be suitable for your device.

Note: This program is still in beta stadium. Please send your bugreports, comments and suggestions to grainstorm@rocks.me.

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