Using Max/MSP with a MOTU 828 to control an E.M.L. synth (1.2 volts/octave)
I'm having trouble figuring this out. The synth is responding to the signal from the 828, sending a sig~ out of output 1 into the oscillators control input on an EML 200 (which is 1.2 v/oct), but I haven't been able to figure out how to use it with a midi keyboard or a sequencer any "musical" 12 tone control of the oscillators yet. I mean, I'm not sure what conversions need to take place etc. Any thoughts?
I did this for my analogue gear by trial and error. First make sure your baby's warmed up and stable. Then patch this...
[toggle]
|
[metro 250]
|
[counter 0 11]
|
| [flonum]
| |
[* 0.]
|
[sig~]
|
[dac] (connected to your VCO CV input)Start the [metro], and tweak the value of the [flonum] until each step of the counter changes your VCO's pitch by a semitone. It might help to attach a second [sig~ 0.5] to the [dac] so you have an audible starting pitch.
Once you have the scaling sorted, you can fine-tune the starting offset so that, say, midi note 60 actually corresponds to C.
HTH :)
BTW, I'm very jealous of your EML. With MaxMSP you are going to really make that baby sing. After your VCOs are sorted, you can use the above technique to tune your filters (provided they have a linear CV input). If you only have log inputs, you only need to make a minor mathematical tweak to your 0-1 output signal. I'll leave that up to you!
get a multimeter and put the terminals on the tip/ring of a jack lead connected to one of your 828 outputs. Set the multimeter to measure DC voltage.
connect a number~ or sig~ + flonum to the dac~ output that goes to the 828 output.
gradually raise the the value you are sending out until you see 1.2 volts on the voltmeter - note down the value. Let's say the value was 0.307. Now you can use the scale object to map semitones to voltage...
scale 0. 12. 0. 0.307
if your synth has good tracking, it should be reasonably in tune without using any kind of pitch tracking (like Volta or silent way does)
hope that helps,
oli
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Thanks So much to both of you! It's working pretty well, looks like there's going to be a lot of number twiddling ahead in order to get the thing to have a nice full range without having the scaling start go funny on me. You guys made my day/night/day. Thanks a million.
J
I'm not sure what the 828's maximum voltage output is, but if you feel like you need a bit more range, you could try using the headphone output. On my Ultralites, with the volume cranked, it gives me an extra octave or so.
Oh, and it's stereo so of course you have two 'high-voltage' channels.
Of course, you'll need to adjust the scaling differently compared to your main outs. And you'll need to wire your cable a bit differently!
Once you've got all this sorted, I'd recommend building a few look-up tables mapping MIDI pitches to output levels for your VCOs and VCFs.
I'm not sure how patchable and voltage-controllable your EML is, but if you have enough connectivity, you can save and recall presets in Max! If you can route the pre-VCA audio from the synth into your computer, try using a software VCA envelope in place of the hardware. Sickness will ensue! Plus you can use MSP oscillators to modulate the analogue... Horrible pitch/filter FM madness is hilariously easy with this sort of setup. :)