I got a keyboard midi controller recently, because I wanted to experiment playing in different tunings on the keyboard, wondering for example how much sweeter a piano may sound if I could use some form of just intonation rather than standard ET.

It was rather a difficult learning curve to set this up, and I could not find too much help on the web for this topic. So I like to share how it worked out for me. I use a Windows XP platform.

I found some interesting and some great sounding VST virtual instrument plugins, which work in Cubase (which came with the keyboard) and in two standalone VSt host players I found (VSTHost http://www.softpedia.com/get/Multimedia ... Host.shtml and MiniHost http://www.tobybear.de/p_minihost.html).

The problem was to set up micro tuning. I was familiar with the Scala software http://www.huygens-fokker.org/scala/ , which is great for loading all kinds of scales and tunings, and writing your own. Scala was taking the MIDI input via USB from the controller keyboard, but then wanting to output to a MIDI synthesizer, like Microsoft MIDISynth. That is, till I found a software internal MIDI "cable" called LoopBe1 http://nerds.de/en/loopbe1.html which is a virtual midi driver. With this driver installed I could direct the Scala output via its Relay settings to LoopBe, and the MIDI input of Cubase and the other VST hosts to LoopBe as well, LoopBe acting as a virtual internal midi cable.

With this setup I was able to retune VST instruments in Cubase and the other VST host shells via the scale file loaded in Scala. But not all VST instruments, some behaved badly, some refused the retuned MIDI input. Some worked well though. I think it depends how the VST has programmed the pitchbend controller. For VST instruments where the pitchbend worked for a semi tone up and down the retuned input usually worked.

Okay, I think this covers the basics. And it is a budget solution, I only paid for the keyboard!
Maybe this can help someone, maybe you can add something!

Not much ... except that I have also played with non-12TET with my MIDI keyboard and virtual synth, and I think it's an interesting exercise. It's amazing how quickly the ear/brain adjusts to a particular intonation, making all the others seem weird. And as with any kind of sensory experimentation (taste, smell, etc.), I need frequent rest breaks before my ear/brain complains about the effort involved.

Perhaps I should add that the complex setup for microtuning I described can be avoided by using some commercial software. For instance Pianoteq http://www.pianoteq.com/ offers virtual piano software, which judging from the demo is quite good, and which has loads of build-in tunings, and let you load Scala scl files as well. The free Kontakt Player from Native Instruments http://www.native-instruments.com/#/en/ ... -5-player/ has also a number of different tunings, and I believe the full Kontakt version lets users load different scale files as well.