GrooVoid - Android Hardware MIDI Companion (Alpha 0.1)
A personal project that slowly grew into a MIDI companion for my hardware setup.
Some time ago I completely stopped making music on my computer. Nowadays I only use it to record individual tracks and later, if needed, for mixing and mastering. My Elektron Syntakt has become the “brain” of my setup, controlling everything else (Edge, Spice, Digitakt II and Pro-800), while my Lenovo Yoga Tab Plus was always sitting next to the gear… Doing absolutely nothing. So I thought it was finally time to give it a purpose.
At first, I only wanted to build a simple visual metronome. Just a small tool that would display useful information like beats, bars and phrases. I guess I’m one of those people who always needs everything to line up perfectly, so instead of focusing entirely on the music, I often caught myself counting bars in my head and waiting for the end of an 8- or 16-bar phrase before making a transition.
Since the Syntakt already sends MIDI Clock, I figured… Why not use it?
That simple idea slowly turned into something much bigger.
If the application can already receive MIDI messages, then obviously it can send them too. One thing I always missed on the Syntakt was a simple random pattern generator. I had also been looking for a small device that could generate some random triggers during jams.
At first, I simply wanted to press one button and see what happened. But after thinking about it for a while, I realized I didn’t actually want completely random triggers. I wanted something that could generate musically useful rhythms — patterns that make sense and serve as a starting point rather than pure chaos.
From there, the project kept growing.
Today it has evolved into a visual MIDI transport, a drum pattern generator, a melody composer, MIDI monitoring and several other tools that naturally appeared during development.
The application has now reached a point where I actually enjoy using it during every jam session. It often generates ideas I wouldn’t have programmed myself and, in a way, it has become an external companion to my hardware rather than another sequencer or DAW.
I’d like to share this early Alpha 0.1 version with you and hear what you think. I’m curious whether I’m the only one who felt the need for something like this, or if some of you would also find it useful.
The application is completely free. I built it primarily for myself, but I thought other hardware users might find it useful too.
What does it do?
GrooVoid currently consists of three modules.
Visualizer
Works with MIDI IN only.
It listens for standard MIDI Clock, Start and Stop messages and displays BPM, beats, bars and phrase progression in real time. Even on its own it works as a visual transport monitor for any hardware setup.
Pattern Generator
The Pattern Generator is always available and immediately generates MIDI patterns. If a MIDI Output device is connected, the generated notes are sent directly to your external hardware using standard MIDI messages.
The selected instrument matters. Kick, hi-hats, percussion, rides and other instruments all use different generation rules and probabilities, so changing the instrument also changes the generated rhythm.
Composer
Generates melodic patterns.
It lets you choose MIDI channel, root note, musical scale and several generation parameters before sending notes to external hardware.
Compatibility
The application uses only standard MIDI messages, so in theory it should work with virtually any MIDI-compatible hardware or software.
Although it was designed around my own setup with the Elektron Syntakt acting as the master clock, nothing in the application depends on Elektron-specific MIDI implementation.
So far I’ve tested it successfully with all of my own gear.
The interface was designed primarily for tablets. It should scale to different Android devices, but I haven’t tested enough hardware yet to guarantee perfect results on every screen size.
I also put together a Windows version, just in case someone prefers using a PC instead of a tablet. It offers the same functionality as the Android version.
I’m currently working on a proper user manual that explains all modules and generation options in detail.
A small note about the REC button
You may notice a REC button in the transport controls.
Originally I hoped to start recording on the Syntakt directly from the application. Unfortunately, after a lot of testing, I discovered that the Syntakt simply doesn’t support starting pattern recording via MIDI.
So, the button doesn’t actually do anything right now! But I decided to leave it there for sentimental reasons.
MIDI Clock accuracy
One thing I noticed during testing is that the displayed BPM isn’t always a perfect 1:1 representation of the incoming clock.
The transport itself (beats, bars and phrases) stays perfectly in sync, but the calculated BPM value may occasionally fluctuate by a small amount. This seems to be caused by the timing accuracy of incoming MIDI Clock messages rather than the transport itself.
In practice it hasn’t affected usability during jams.
Current status
This is the first public Alpha (0.1) release.
The application has been tested extensively with my own hardware setup, but this is the first time it is being used outside my studio.
If you decide to give it a try, I’d really appreciate any feedback, bug reports, or feature suggestions right here in this thread.
This project started as a personal tool, but I’d love to see where it could go with input from other hardware users. I’m sure there are still bugs and rough edges, so please don’t hesitate to point them out.
Downloads
Android
GrooVoid_v0.1.0_Alpha_Android.apk
https://1drv.ms/u/c/b516c1b80457d040/IQDvei0UzpFZQrViZYTMVR30Aca52SzPEIgPK-hYyD0itb8?e=o2L798
Windows
GrooVoid_v0.1.0_Alpha_Windows.zip
https://1drv.ms/u/c/b516c1b80457d040/IQBgxlAoYXCBQbgmXJePUlkVAYK26qKWazy9i4t8EVg66QA?e=Lt2DqQ
(The files are hosted on my personal OneDrive. If anyone has concerns about downloading the APK, I’m happy to upload it somewhere else as well.)