Dan Lavin
Joined: Nov 09, 2006 Posts: 649 Location: Spring Lake, Mi, USA
Audio files: 21
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Posted: Tue Jul 01, 2014 11:19 am Post subject:
Midikit Midi Channel Filter Implementation Subject description: A Midi Channel Filter makes the GM Voice work better in a multi-inst. set-up |
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One of the problems with the GM Voice, either the original or my update earlier this year, is that it does not work well in a multi –synth midi set-up. It responds to all Midi channels, all the time. Most of the time, I would just like to use it for piano, organ or strings…..just as a single voice. I’d rather have separate synths for bass, lead and drums. There’s ways around this using midi volume, but that could also affect the desired midi synth as well. It’s messy to say the least.
Tom Scarff has been designing midi controllers and hardware aps for some years now. I’ve been using his PIC16F877- based bass pedals for a number of years with good success. Most of these aps he sells, but he does have a couple Arduino aps that you can download the source code for: ( http://www.midikits.net/downloads/downloads.htm ). I chose the midi channel filter to correct the problem above. The midi channel filter will take incoming midi data and only pass the one channel selected and reject all the other channels. Now my GM Voice is single midi channel selected.
Full project description at http://www.midikits.net/midi_chan_filter/midi_channel_filter.htm
The code is a bit dated and needs some corrections. If you load it into the Arduino programming software and select verify, it will walk you through the process, but it comes down to changing all the “print” commands to “write”. Also, deleting the word “BYTE” in those write commands is needed. That’s it! It worked like a champ first time I wired up.
You’ll need an arduino (I used an Arduino Uno), the 6N139 or optoisolator of your choice, two midi jacks (one in and one out), a 1N914/1N4148 diode, a little bit of perfboard and a couple of resistors and 4 switches to select the midi channel (hexadecimally). I plan on using a rotary hexadecimal switch. You can use Tom’s Miduino schematic to create the circuit, (http://www.midikits.net/miduino/miduino_ct.GIF). In addition, if you build my updated version of the GM Voice, I believe you could mount the Fluxamasynth directly to the Arduino and not worry about the midi output jack. I haven’t tried this out yet, but Tom’s code and pin outs look compatible with the Fluxamasynth. You’d still need the Midi in jack and a little perf with the midi input circuit, though. Tom does sell a little board to handle the midi in/out and switches if you’d prefer. Then it’s a wholly pull-n-play solution. _________________ Synth DIY since 1977! |
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