Hello Everyone,
 
I just purchased a used Sequential Circuits Pro One synth, and I am wondering if I am somehow able to use controllers in Cakewalk to somehow draw in parameters on my Pro One (such as filter cutoff, resonance, etc...).   

The synth has a CV/Gate in but is CV/gate only for note on-off? 
 
Ive seen MIDI to CV/Gate converters, but if its just for notes, I don't need that.   I would like to draw in my synth parameters rather than adjust by hand.
 
I hope I stated clearly what I am looking to do.  I am new to the CV/Gate world.
 
Thank You!

I am not familiar with that synth, but if it just has CVGate and not MIDI in you won't be able to control knob parameters remotely. CVGate is just for note/pitch control from what I know.

so I can control the Filter cutoff as it has filter CV in, but I think i need a MIDI CC > CV/gate converter in order to do it inside Sonar. correct me if I am wrong.

Sonar only sends out MIDI data.  Since that synth was built before the MIDI standard, you will need to convert.
 
https://en.wikipedia.org/wiki/CV/gate
 
http://www.vintagesynth.com/sci/seqpro1.php
 

You're right. Sonar can send out and receive MIDI data.

If you device doesn't speak MIDI you'll need some hardware to translate for you. You'll probably find it cheaper to get a controller keyboard and have all the sounds played in side Sonar via VSTi plugins and use the controller keyboard to write your midi messages recorded in Sonar. Controller keyboards are relatively cheap. I'm not sure how expensive MIDI to CV vice versa hardware would be not to mention availability.

Much easier and more straight forward get a $150 to $300 controller keyboard and never look back.

For $99 there is always this plugin to take you back to 1981 from Urs Heckmann at u-he. 
 
https://www.u-he.com/cms/repro-1

I recently sold my Pro One.
 
There are two CV ins on the back. One determines the note value, the other controls the filter only.
A midi-to-cv converter should at least control the note value (CV) and timing (gate) for one note. Beyond that, it may offer multiple CV outs and may be configurable to respond to MIDI mod wheel, or something else, to control a 2nd CV. So it's really up to the converter to provide the control you need. But the Pro One does not have a way to have its other parameters be controlled by CV or any other automated means. (A robotic knob-twister?)
 
I noticed a midi retrofit for the Pro One from Kentron. But I don't think it offers control of any other parameters.

Thank you for the help everyone.   Really appreciate it.
 
OH and yes, i knew about the u-He plugin, but hardware is so much easier to use really.

Doepfer make MIDI to CV converter boxes that aren't very expensive, and the Dark Time sequencer is MIDI clockable and sends CV. As does the Boss/Roland Sq-1.

As for controlling parameters via external CV sources, if the synth doesn't have the necessary inputs it can't be done. A lack of MIDI control does have some advantages though. MIDI only has 128 values, assuming it's the usual 7bit variety. This means that MIDI "continuous controllers" actually aren't continuous at all but go in steps. This can be particularly noticable when manipulating filter frequency or pitch slides and you get a 'zipper' noise if the change is fast or a series of steps if the parameter is changing slowly. It's particularly noticable at high frequencies where the Hz difference between notes is greatest. CV control does away with that, though it does mean turning knobs.

The Pro One's a nice synth, my advice is to use it for its strengths and the quality of the sound. If you really want something very similar but entirely MIDI controllable the DSI Mopho and Prophets are the things to look at. Or maybe a more modern MIDI controlled synth to go with it.

mudgel
You're right. Sonar can send out and receive MIDI data.

If you device doesn't speak MIDI you'll need some hardware to translate for you. You'll probably find it cheaper to get a controller keyboard and have all the sounds played in side Sonar via VSTi plugins and use the controller keyboard to write your midi messages recorded in Sonar. Controller keyboards are relatively cheap. I'm not sure how expensive MIDI to CV vice versa hardware would be not to mention availability.

Much easier and more straight forward get a $150 to $300 controller keyboard and never look back.

The idea is to go in the other direction, to control the hardware from Sonar. The Pro One is a desirable vintage synth.

I say just record audio. Overdub in case of problems. All famous recordings of Pro Ones have been done that way.