top of page

How to mirror the keyboard on digital pianos via software

by Peer Oehlschlägel

In preparation for a music education workshop on "handedness in instrumental lessons", I once again did some internet research. That's how I came across the "web midi mirror".

This small program uses the "Web Midi" protocol and works with Google's Chrome browser on any laptop/PC regardless of its operating system. It was written in 2019 by Stéphane Soppera and can be found online here (external link). It can also be downloaded and used without an internet connection.

I have been retraining to use my left hand since 2003 and pay particular attention to how I fare with left-handed activities. On My main instruments, the percussion instruments, I play almost exclusively left-handed. However, there are instruments that I have tried to learn but have not been able to make my own in my life so far. For example, I couldn't manage the right-handed guitar at all, while I found it easier with the piano. I made it as far as an advanced beginner on the piano and was able to teach beginners on this instrument. For myself, I occasionally play left-handed electric piano to unwind and enjoy the relaxation that comes with it.

When I used to sit down at the piano (as an unrecognized left-hander on a right-handed instrument), it was always a hard piece of work. From time to time, I looked at the options for "repoling" an electric piano.

I first came across the "Bome Midi Translator" several years ago. I also managed to mirror my keyboard with the free version. You can read an article about this on Linksgespielt. However, it is relatively time-consuming to carry out this "mapping".

A few years later I discovered the program "MidiPipe", which only runs on MacOS (Apple computers). However, it can do the same as the Bome Midi Translator with the help of an existing file (Mirrored Piano.mipi) and is free of charge.

Both programs, Bome Midi Translator & MidiPipe, are actually designed for the versatile processing of MIDI messages and can do everything possible to control MIDI devices.

The "web-midi-mirror" is actually like a hardware keyboard mirror: it only has this one function and is therefore easier to use. A hardware mirror is of course the best quick and easy solution because it is small and portable.

However, the "web midi mirror" is probably more cost-effective, if you have a laptop/PC. You then only need to purchase a midi interface costing from around € 20.

A tablet is connected to an electric piano
The web midi mirror on a small tablet PC on my Clavinova

The photo shows the simple buttons for selecting the midi interface and the LOCAL CONTROL switches in the browser window. LOCAL CONTROL means that the internal sound of the electric piano can be switched on/off.

When playing left-handed, LOCAL CONTROL must be switched off so that only the "mirrored" sound can be heard and not both at the same time (original & mirrored). The fact that this command is controlled remotely (from the browser) means that you don't have to look in the electric piano's menu to find out where to switch it off, which can be a somewhat complicated process and is different for every brand.

Heidi Schneider thankfully pointed out one aspect of the reversed electric piano to me: If the keyboard is successfully mirrored, the sound unfortunately comes from the wrong side! If you want to have an authentic listening experience here, the stereo sound would also have to be reversed left/right.

Electric piano with external speaker boxes to the left and right of the sheet music and tablet.
Solution: Clavinova with extra speakers

If you play with headphones, the problem is easier to solve: turn the headphones around!


Setup scheme: Computer display - USB MIDI interface - electric piano

I have tested 3 types of MIDI interfaces with the web-midi-mirror according to the setup scheme above:

  1. Made by TIE: an inexpensive USB-MIDI interface for approx. 20,- €.

  2. Maded by Presonus: the AudioBox96, an audio & MIDI interface for approx. 95,- €.

  3. Made by ESI: a pure 4-channel MIDI interface, for approx. 140,- €.

All interfaces are connected via USB to the computer and via MIDI cables to the electric piano:

The Interface's MIDI Out is connected to the electric piano's MIDI In and vice versa, the Interface's MIDI In is connected to the electric piano's MIDI Out.

Unfortunately, the cheapest MIDI interface does not work with a Windows computer. It is therefore worth choosing a more expensive product when purchasing a new one.

Web midi mirror test

Table on the compatibility of the tested interfaces with different operating systems. Result: The "AudioBox96" and "ESI M4 U" interfaces work with Mac OS, Windows and Linux. "TIE", on the other hand, only works with Mac OS and Linux.

Summary: Software for keyboard mirroring

The "web-midi-mirror" program can be downloaded free of charge and works on any laptop/PC with a CHROME browser (or compatible browsers). Once downloaded, it can also be used without Internet connection. It is even easier to use than a "hardware mirror" as the LOCAL-OFF command is controlled remotely.

If you already have a MIDI interface, you can mirror the keyboard of an electric piano free of charge.

If you are considering buying a "hardware mirror", you may be able to save some money because you only need to purchase a MIDI interface. If you are buying a new MIDI interface, make sure it is Windows-compatible if you are using Windows.

In order to adjust the sound experience of the mirrored keyboard, the right speaker must be swapped with the left speaker to achieve the correct surround sound. This can be achieved with extra speakers. This problem does not arise if the electric piano has no built-in speakers or is played with headphones.

Photo credits: Peer Oehlschlägel


bottom of page