MP-201 as Midi-CV Converter??

[Portamental]

Sorry if it's a stupid one!

I've no experience with CV/Gate, but am interested in the old school. I read in the SOS review that the reviewer had a problem with keyboard tracking as the CV input needs to be calibrated. Is this necessary when using the MP-201?

Basically when you connect the OS to the MP-201 does it just play back the correct midi notes without any complicated adjustment?

Thanks

It's a legitimate question. Many things have been written, here included, many I find misleading. I have always found my OS finely in tune with two other midi-to-CV I use (and other musical instruments of course). And this question keeps surfacing now and then with often the same vague answers.

You had to ask? I had to check, and put the matter to rest!

I used a Kurzweil 2500x as pitch reference and as midi controller. First thing first : an audio test. The audio of Kurzweil is routed into the OS. OS settings : a single osc, square wave, switch on 16', no cutoff. Both sounds heard in same headphones. Pressing C4 on Kurzweil, C4 on Voyager. Same pitch. All Voyager's keyboard range is absolutely tuned to the same range on the Kurwzeil. The OS just passed standard tuning test.

Next, MP-201 is called in. Standard midi-to-cv preset 34 is used, root note 60 (which is C4), CV1 into Pitch, CV2 into gate (no changes or calibration to the preset). I press C4 on the Kurzweil, I hear a C4 Voyager note along with the C4 piano sound, both finely in tune. Then pressing all keys on the Kurzweil all the way up to the last. Voyager responds with the same note, finely tuned in pitch with the Kurzweil. No audible variation over a 4 octave range. Next, I change the root note on the MP-201 24 steps down (2 octaves). Voyager now plays 2 octaves lower and I can detect no difference in pitch over a 5 octave range this time, the full swing of the positive CV pitch range.

One would have thought that the MP-201 could have converted notes lower than the base note to negative voltage CVs, but apparently not. Conversion stops as the base note, keyboard keys (on the remote keyboard) lower than base will only play the base note. That's a bit peculiar since the pitch input CV of the Voyager is designed to swing -5 to 5 volts. Bipolar mode does applies to midi-to-cv. This is a little shortcoming that I really think should be addressed in a future firmware release. That does not prevent you from playing in lower keys, just press a key on the Voyager (or use the octave switch) to change it's own internal voltage reference.

But tuning issues ? I can not detect any. As far as I am concerned, the matter is settled.

[vin13]

.. for going to the trouble of conducting that test. It was most helpful, cheers.

[Portamental]

The MP-201 has performed midi-to-cv role mainly for me, doing well. In the above tuning test, I had the pedal in unipolar mode and I was looking into the preset settings to switch to bipolar mode, but no such option was available. So the MP-201 was doing 0-5 volt midi-to-cv.

Upon reading the finer print in the manual to make sure I did not miss some essentials (and i did), i came across the bipolar mode as a global unit setting, and not one for each preset. I did not have to use the feature before.. but now....

And as is printed in black and white in the MP-201 addendum, the pedal in bipolar mode will span the whole CV range (-5 to 5) in midi-to-cv mode, which is confirmed by the display set in voltage units, and also by my now full range Voyager, when played from a 88 notes keyboard. That's quite a glide.

So all is well in the negative CV world afterall. I find that positive

[erer]

noob question....

i have...
2 freqboxes,
one cp251,
one low pass filter,
one midi controller,
one mp201.

with the recent addition of pitch to cv to the mp201...am i able to create a dual oscillator keyboard set up?

plug a midi controller into the mp201...have the mp201 do some midi to cv converting on 2 channels...then run those cv outs to the frequency expression jacks on my mf107s...run both audio outs to the mixer of the cp251...take the summed signal and put it through the filter.

would that work?

[Portamental]

Interesting question for which I don't have the definitive answer yet. I find the freqbox very intriguing. My next fooger no doubt. I just got the MF-101, I have yet to REALLY learn how to use. I have pretty much the same goal as you regarding the freqbox, except in a one Osc set-up driven by the Etherwave.

As i understand the freqbox, I think your setup should work, except for one thing. The freqbox needs an audio tone to align it's frequency to. Instead a using a plain midi controller, you would have to use a midi tone generator, such as any entry level Yamaha midi keyboard. Set the keyboard to a rounded, yet steady sound (sharp organ) and play monophonic lines. By setting the Mix on the freqboxes to 0, the audio tone will not be heard, only the osc of the freqbox.

If I were to try a similar setup though, my first try would have the freqboxes daisy chained, with the MF-101 at the end. The first freqbox would receive midi keyboard audio, with Mix to 0, the second freqbox would align on the first one's audio, with mix to taste. The MP-201 can the be configured with 2 more possible gates channels, one of which will go on MF-101, for sure. Maybe use the fourth channel for an expression pedal. The mixing of both freq audio output being done in the audio chain, that leaves the CP-251 free for other uses : mult and/or mixer for more gates or exp cv (from the MP-201) to the freqboxes. I wonder just how many combinations are possible there.

That's a plan (the one freqbox version of it) I hope Santa will help me realize

[Amos]

noob question....

with the recent addition of pitch to cv to the mp201...am i able to create a dual oscillator keyboard set up?

Yes and your plan will work; if you are sending a pitch CV to the FreqBox then it does not need any audio signal; you'll get a signal from the OSC OUT jack all the time. It's only the MIX OUT that requires an audio input signal in order to get an output signal.

This does bring up a useful point, which is that the only ingredient you're missing compared to a classic mono synth is a VCA (voltage-controlled amplifier) and gate, to cut off the sound in between notes.

You might be able to fake it by using a third channel of your MP-201 as a Midi-controlled envelope generator, and connect the CV output from the Envelope to the Cutoff CV input on the filter. Then turn the filter cutoff knob to zero. If the Env Amount on the filter is also at zero and the filter Mix is 100% wet, then the unit should filter out all of your sound until you press a key and fire the envelope, which should open the filter enough to let sound through. Not quite the same as having a real VCA in the chain somewhere, but it should be close enough to do some interesting stuff...

[Portamental]

if you are sending a pitch CV to the FreqBox then it does not need any audio signal

That's the one answer to the one question. May be Santa will show up early knowing this

[Amos]

If I were to try a similar setup though, my first try would have the freqboxes daisy chained, with the MF-101 at the end. The first freqbox would receive midi keyboard audio, with Mix to 0, the second freqbox would align on the first one's audio, with mix to taste.

This, however, works perfectly just as you describe it... and the audio-signal input does gate duty for your two freqboxes that way. The result will sound very much like a 2-VCO synth with Moog filter!

[erer]

badass. thx dudes

[tubeampguy]

noob question....

with the recent addition of pitch to cv to the mp201...am i able to create a dual oscillator keyboard set up?

Yes and your plan will work; if you are sending a pitch CV to the FreqBox then it does not need any audio signal; you'll get a signal from the OSC OUT jack all the time. It's only the MIX OUT that requires an audio input signal in order to get an output signal.

This does bring up a useful point, which is that the only ingredient you're missing compared to a classic mono synth is a VCA (voltage-controlled amplifier) and gate, to cut off the sound in between notes.

You might be able to fake it by using a third channel of your MP-201 as a Midi-controlled envelope generator, and connect the CV output from the Envelope to the Cutoff CV input on the filter. Then turn the filter cutoff knob to zero. If the Env Amount on the filter is also at zero and the filter Mix is 100% wet, then the unit should filter out all of your sound until you press a key and fire the envelope, which should open the filter enough to let sound through. Not quite the same as having a real VCA in the chain somewhere, but it should be close enough to do some interesting stuff...

I cross patched the Osc out to the Audio in to try and buffer down the signal. The input pot is counter clockwise all the way and the Mix knob is at 12:00 O Clock. I haven't figured out how to approximate a VCA or patch the gate with this simple patch. Any ideas?

[erer]

i was maybe going to check out the pigtronix attack sustain for a pseudo vca

might be sweet...what do you dudes think?

http://pigtronix.com/products08/attacksustain.html

[Lux_Seeker]

Very cool. I really like the capabilities of this gadget. The only drawback I keep imagining is programming it. If it were a desktop objet that would stay put, then tweaking it would be fine. But using the foot pedal would be primary for me so I'd keep it on the floor, and the thought of picking it up off the floor (with a half dozen cables sticking out the back) every time I want to make a tweak doesn't appeal to me. I realize setups can be stored as programs, so that would help a little. Still, it's a negative to me. If the MP-201 had a software editor, I'd have no choice but to buy it.

I guess I don't see having a fixed setup for this pedal so I will be doing a lot of moving around of cables. You could label cables at both ends as CV 1-4 which would make it easy to reconnect them and to connect them into foogers, Voyager, Phatty, ect at the other end.

[GregAE]

You could label cables at both ends as CV 1-4 which would make it easy to reconnect them and to connect them into foogers, Voyager, Phatty, ect at the other end.

In Electronic Musician's review of the MP-201, the author suggested using colored cables to keep track of which cable came from which channel output. A color-coded scheme should make it very easy for quick repatching.

- G

[Portamental]

In Electronic Musician's review of the MP-201, the author suggested using colored cables .....

Are you saying some people are NOT using them ? I got a pack each of Hosa's 1.5 and 3 feet colored patch cable. I bought them initially because I was tired to make my own and they were nagging from the pegboard. After using colors, you don't want you life in black again. Visitors are attracted to them bright colors, a good opportunity to show the real jewel underneath (Voyager OS)

No luck getting an MF-107 today, dealer out of stock So I won't be able to try the MP-201, MF-101, MF-107 combo this week end.