Controlling pitch bend for Audio Unit instruments

The Eigenharp’s keys are extremely sensitive and one of the first challenges when learning to play it, is to control accidental pitch bends while applying more pressure. Eventually this should be possible to configure through Belcanto when Eigenlabs releases the Workbench, however in the meantime I have found a solution for Audio Unit instruments that seems to offer a good compromise.

One of the things that makes the Eigenharp so expressive is that notes are never fully in tune, like with stringed acoustic instruments. Even if you play the note perfectly, there are always minute continuous variations that make the sound come alive. This is something you certainly don’t want to lose. Another great feature of the Eigenharp is that you can pitch bend notes on the keys themselves and don’t have to reach out to a separate pitch bend wheel, we certainly don’t want to lose that either. However, in between these there’s a whole range of accidental pitch bends that you might want to eliminate.

To keep the pitch bend under control, I use Plogue Bidule. It’s basically an audio and MIDI patching application that you can use to transform, generate, trigger, sync, … anything sound related. Apart from being able to run standalone (I use it as a host for my live guitar effects and MIDI triggering), it also runs as an Audio Unit instrument or effect which can host other Audio Units or VSTs.
So, instead of running Omnisphere (or any software instrument) directly as an Audio Unit instrument in EigenD, I first run Bidule as an Audio Unit and then instantiate and wire up Omnisphere inside Bidule. However, before sending MIDI to Omnisphere, I first filter the pitch bend messages. The full range of pitch bend messages goes from -8191 to 8191 and I keep the first 30 values (from -30 to 30) to have the minute continuous changes, but then filter out everything until the values -300 and +300.

The first thing to do to get this working is to install the Plogue Bidule Audio Unit (requires a commercial license of the software which costs only $79) and then select it through the EigenD browser as an Audio Unit 1 plugin:

You’ll then have a Bidule window open and you can go to the File menu to open the ‘Bidule Pitchbend Control‘ file I attached to this post (unzip it first):

This should show you the patch I set up with Omnisphere already in there as an instrument and a MIDI monitor window open for debugging:

You can now double-click on the ‘Omnisphere’ module, open the UI and play around with it as usual.

Do let me know how this works out for you and if you’re making changes that could be useful for other Eigenharpists. To me this gives some control over the sensitivity of the Eigenharp without having to wait for a full Belcanto understanding.

(Bidule patch Bidule Pitchbend Control.bidule)