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Hardware Instruments => MatrixBrute => MatrixBrute - General discussions => Topic started by: charloctave on April 11, 2019, 05:44:31 pm

Title: CV in/out...
Post by: charloctave on April 11, 2019, 05:44:31 pm
I'm so new in this forum that i don't even know where to post my question...
I drive my MB with the CV outputs of my theremin: mainly the pitch antenna CV into the MB VCO1 input, and the volume antenna CV to a filter CV input. Can I patch a CV output to another module CV input to control more than one parameter with my antennas ?
For example, if I drive the steiner filter, can i also drive the ladder filter by patching the steiner CV out to the ladder CV in ?
Of course i tried, but it doesn't work... is it normal? how can i do?
Title: Re: CV in/out...
Post by: DrJustice on April 11, 2019, 07:37:42 pm
Welcome to the forum :)

Yes, that's normal. On the MatrixBrute, the CV inputs go straight to their labeled function and does not appear on, or are being mixed with, the corresponding CV outputs.
What you need to do to control both filters is to use a multiple (several jacks connected together for distribution of a single signal, often found on modular synths), or a split/Y cable and connect the one CV output from the Theremin to both the Steiner and Ladder CV inputs on the MatrixBrute.

Edit: It's not that critical where you post this question - it could be here, or perhaps in Technical Issues or Tips & Tricks.
Title: Re: CV in/out...
Post by: charloctave on April 12, 2019, 11:18:57 am
Thank you doctor!
I don't know much about CVs... If I use a split/Y cable, will it divide the voltage by 2 ?
also : could my demand be a feature request for the next MB OS upgrade, or does it involve the hardware itself?
Title: Re: CV in/out...
Post by: DrJustice on April 12, 2019, 03:52:51 pm
The voltage will be the same, you just send it to 2 places simultaneously (if you go by the physics of it, there will be double the load so the output will drop a very tiny amount, but this has no effect in practice and is how it's done - that's one of the things that makes voltage control very convenient).

Here are some examples of what you can use (I  used Thomann for these examples, most synth shops have similar things, especially if they deal in modular synths):
Multiple ( (handy little thing)
Stackable cable ( (you can plug another plug into the plug...)
Split cable ( (you'd need two male/male cables - the one shown here is stereo, but that doesn't matter as only the tip an shield part is used)

The MxB's CV arrangement is in hardware, so it'll have to stay as it is.
Title: Re: CV in/out...
Post by: charloctave on April 12, 2019, 05:25:58 pm
Thanxx again ! the blue star shape stuff should do it perfectly
just one more question before i drown back into my experimentations: can i launch/trig on an MB sequence with the gate out of my theremin?
Title: Re: CV in/out...
Post by: DrJustice on April 12, 2019, 08:59:26 pm
Almost, but not quite... Do you want the sequencer to play as long as you hold a note, or do you want it to play single notes, advancing one step for each gate you send? Both launching the sequencer and trigging it step by step is not supported through the MxB's gate or sync inputs. The things you CAN do are:

- Play the sequencer from an external MIDI device, just as you can from the MxB keyboard, but no step by step triggering.

- By connecting the the Theremin gate output to the MxB Sync input, and using the MCC to set "MIDI clock source" to "All" or "Sync" and setting the "Sync Clock In/Out Settings" to "1 step (Clock)", then setting the MxB's MIDI Sync to on and selecting 1/16 notes, you can get the sequencer to trig step by step if sending a fairly steady stream of gates. This isn't real step by step trigging though (in reality it calculates a tempo from the incoming sync pulses), so if the gate tempo changes or you stop sending gates, you may lose a step or get more that one step.

So, in this area there is grounds for a feature request. E.g. a new "Sync Clock In/Out Settings" of "1 step per clock". There''s one dilemma here though; how long should the gate time of the note be? Normally, when the sequencer runs it has a tempo and thus it can calculate the internal Gate length to use per step. The solution might be to treat the Sync input as a Gate/Advance input and, playing each step for as long as the gate is held open, then advancing to the next step on the next gate.

Another feature request might be to have the Gate input do the above, with a corresponding configuration parameter in the MCC. Currently the Gate input will just play a steady note, not start the sequencer (if the seq is enabled) as is done for notes received by MIDI. However, I'm also thinking that this feature could "just work" without any configuration, by treating the Gate input just like a received MIDI note or a note played on the MxB's own keyboard.

Hmm.... perhaps we should submit the latter as a feature request?
Title: Re: CV in/out...
Post by: DrJustice on April 14, 2019, 03:56:12 pm
In the above reply I forgot to mention that you can use a CV/gate to MIDI converter to control the MxB, or any other MIDI equipped gear, from the Theremin.

There are several to choose from, and example is the Kenton Pro CV to MIDI Converter (

Title: Re: CV in/out...
Post by: endreola on April 15, 2019, 07:42:37 am
Nice choice.  From my experience the guys at Perfect Circuit are very helpful, maintain a good stock of inventory, offer free Fedex delivery and provide top notch customer service.  Their showroom is chocked-filled with wall to wall gear and is well ogranized and maintained. Yea, I am just a customer and have no other business affiliation with them.

As for the Theremin or the Kenton controller I can't offer much in that area but think it's a cool controller and it sure sounds like fun. I do like Moog's Theremin as it offers auto scales which will help this noob to produce something more melodic than the sounds of fingernails against a chalkboard.  Maybe I'd rig one up using a pair of robotic arms :)  And speaking of controllers, it would have been cool if Arturia included a ribbon strip controller with the MB, at least it appears there's room for one :)
Title: Re: CV in/out...
Post by: charloctave on April 15, 2019, 11:36:26 am
I tried the "1 step per clock" and it works fine ! thank you !