Korg Forums

I'm looking into building my own analog synth (I have experience building instruments, and my father has 40+ years of experience building instruments and was a design engineer, so we will do it right), but I had a pretty major question.
We were wondering, how do we go about interfacing the synth with the app (outside of using something like the Alesis iO dock)? I saw on the main site that there were some channel numbers for all the knobs and patch cables, do we simply program the midi board to assign the channels to the knobs on the hardware?
Sorry if my question is poorly worded, I am not that familiar with the jargon. We'd appreciate any help we can get!

If I were you, I'd call up somebody like Dave Smith at DSI and ask him for advice... the questions you have are deep and fundamental, and won't be answered by a quick forum post.

I too am curious about this, and have been considering the idea of making a MIDI version of the SQ-10 sequencer to go along with my MS-20 Legacy Controller and iMS-20.

Are you making something that is just a hardware MIDI interface to go with the iMS-20 or are you also trying generate sound from the device?

If it's just MIDI, you'll need to look into microcontrollers. Otherwise, you'll need to look into converting voltage to MIDI, which I think could be pretty interesting.

Companies like Doepfer and a few others produce controller boards for connecting potentiometers to MIDI-over-USB or just plain old MIDI.

If all you want to do is create a controller for the iPad app... Then well first of all you're not really "building my own analog synth" just a MIDI controller for a digital synth app. The two are very different things.

If you can find out the controller numbers, then you should be able to program any controller board to send the appropriate CCs for each knob.

I suggest you read up a bit about what MIDI really is and what messages make it up.

Found this many months ago can't remember where...never looked into it 'cos Im not a MIDI expert...hope it helps!


Parameter NameCC# No. (hex) 
VCO1WAVE FORM 77 (4Dh) 
PW ADJUST 14 (0Eh) 
SCALE 15 (0Fh) 
VCO2WAVE FORM 82 (52h) 
PITCH 19 (13h) 
SCALE 22 (16h) 
VCO MASTERPORTAMENTO 5 (05h) 
MASTER TUNE 18 (12h) 
FREQ MOD MG/T.EXT 12 (0Ch) 
FREQ MOD EG1/EXT 93 (5Dh) 
VCO MIXERVCO1 LEVEL 20 (14h) 
VCO2 LEVEL 21 (15h) 
HPFCUTOFF FREQUENCY 28 (1Ch) 

PEAK 29 (1Dh) 
CUTOFF MOD MG/T.EXT 30 (1Eh) 
CUTOFF MOD EG2/EXT 31 (1Fh) 
LPFCUTOFF FREQUENCY 74 (4Ah) 
PEAK 71 (47h) 
CUTOFF MOD MG/T.EXT 85 (55h) 
CUTOFF MOD EG2/EXT 79 (4Fh) 
MG WAVE FORM 76 (4Ch) 
FREQUENCY 27 (1Bh) 
EG1 DELAY TIME 24 (18h) 
ATTACK TIME 23 (17h) 
RELEASE TIME 26 (1Ah) 
EG2 HOLD TIME 25 (19h) 
ATTACK TIME 73 (49h) 
DECAY TIME 75 (4Bh) 
SUSTAIN LEVEL 70 (46h) 
RELEASE TIME 72 (48h) 
ESP SIGNAL LEVEL 11 (0Bh) 
LOW CUT FREQUENCY 88 (58h) 
HIGH CUT FREQUENCY 89 (59h) 
CV ADJUST 90 (5Ah) 
THRESHOLD LEVEL 91 (5Bh) 
OTHERS WHEEL 1 (01h) 
MOMENTARY SW -- Channel Pressure 
OUTPUT VOLUME 7 (07h)

X-Trade wrote:Companies like Doepfer and a few others produce controller boards for connecting potentiometers to MIDI-over-USB or just plain old MIDI.

If all you want to do is create a controller for the iPad app... Then well first of all you're not really "building my own analog synth" just a MIDI controller for a digital synth app. The two are very different things.

If you can find out the controller numbers, then you should be able to program any controller board to send the appropriate CCs for each knob.

I suggest you read up a bit about what MIDI really is and what messages make it up.

Thank you!