CV Switching – Reason101

At some point when working with CV, you end up wondering if you can expand beyond the limits. For example, if you have a Matrix loaded with 32 pattern banks, you’re going to wonder if you can push it to 64. If you have an Arp applied to an instrument, you’re going to wonder if you can have two Arps applied to the same instrument. I know that’s what I was wondering a few nights ago. And that’s the subject of this article. How to expand upon CV connections by switching between these CV devices in real-time.

You can download the project files in the following zip file: cv-switching. These project files include 2 Combinators that show you how to switch between two matrixes or two Arps on the fly. Both Combinators are connected to the same mixer, so to hear each one separately, just mute/solo each one and press play on the Transport bar.

Switching between 2 Matrixes

First open up a new document, and first place a 14-2 Mixer at the top (if you are in Record, you won’t need the mixer, because everything gets tied to your BIG mixer).
Now, open up a Combinator and holding Shift down, place a sound source at the top (for example, a Subtractor), a Thor underneath that, and then two Matrixes underneath the Thor.
Next, flip the rack around and let’s route the audio up. Route the Left Audio output from the Combinator to Channel 1 on the mixer. Then Route the Audio out of the Subtractor to the Left audio In of the Combinator (From Devices).
Now for the CV routings. Route the CV 1 and CV 2 Modulation outputs from the Thor to the Gate and CV Sequencer Control section of the Subtractor, respectively. Take the Note and Gate CV of Matrix “A” and route them to the CV 1 and CV 2 Modulation inputs of the Thor, respectively. Finally, route the Note and Gate CV of Matrix “B” to the CV 3 and CV 4 Modulation inputs of the Thor, respectively.
Proper CV routings for the Thor and Matrix A & B devices
Flip the rack around. On the Subtractor, select a patch you like, or program in some patch parameters that you want to hear. Alternately, leave the default init patch as it is.
On the Thor, completely initialize the patch by turning Oscillator 1 Off, Bypassing Filter 1, turning off the Mod/Filter/Amp/Global envelopes, and reducing the Range, Polyphony, and Release Polyphony down to zero (0) in the Global section. We’re using Thor purely as a CV switcher between the two Matrixes.
In the Modulation Matrix area of Thor, enter the following:
CV In1 : 0 > CV Out 1

CV In2 : 0 > CV Out 2

CV In3 : 0 > CV Out 1

CV In4 : 0 > CV Out 2

A completely initialized thor, with the proper routings in the Modulation Bus Routing Section (MBRS)
In the Matrix A, fill up all 32 of your pattern banks with random patterns or midi patterns that you want to use to play the Subtractor. Random patterns are just quicker for the purposes of this exercise.
In the Matrix B, do the same. However, note that in the example file I have not loaded any patterns into Matrix B. This is so that you can hear the difference when you swtich between Matrix A and Matrix B. But for practical purposes you’ll want to load up all 32 pattern banks with more patterns with which to play the Subtractor sound source.
In the Combinator’s Programmer, select the Thor device (I call it the CV Switcher) and enter the following settings for the Modulation Routing:
Button 1 > Mod 1 Dest Amount : 100 / 0

Button 1 > Mod 2 Dest Amount : 100 / 0

Button 1 > Mod 3 Dest Amount : 0 / 100

Button 1 > Mod 4 Dest Amount : 0 / 100

The Combinator's Modulation Routings for the Thor device (CV Switcher)
For the Matrix A and Matrix B devices, enter the following programmer modulation (for both Matrixes):
Rotary 1 > Pattern Select : 0 / 31

Now, when you press the play button on the Transport, both matrixes will engage, but only one will be used to play the Subtractor, depending on the on/off state of the first button on the Combinator. This first button determines which Matrix is used (if off, Matrix A is used. If on, Matrix B is used). The first Rotary on the Combinator moves through all 32 pattern banks of both Matrixes, thus allowing you access to 64 pattern banks to apply to your Subtractor sound source.

Everything gets switched using the Thor. And the beauty of this type of setup is that you don’t need to worry about Matrix delay problems. Since both Matrixes are always running, and the Thor is used to switch between them, the switching is done completely in real-time with no latency whatsoever.

Ramping it up with an Arp

I won’t go into too much detail about applying this same technique to an Arp. You have the sample file, and you can open this up and see how it’s done. But basically, instead of two Matrixes, you have two Arps that are going through two Thors (one Thor controls the Note / Gate CVs, and the other Thor controls the Pitch/Mod wheel CVs).

One other difference is that you will need a separate Matrix to play the Combinator (ie: the Matrix Note / Gate CV will be sent to the Combinator’s Sequencer Control). This is to ensure something is triggering your sound source, whereas in the previous Matrix example, the matrix units themselves were triggering the sound source.

Alternately, if you don’t want to trigger your sound source via the Matrix, you can set up two sequencer tracks (one for each Arp device) and add your midi note clips there. If you want to switch between both Arps and have them both playing the same part exactly, just duplicate the note clips on both Arp tracks so they are identical. Or have some fun switching up the notes. Experiment with this one.

Proper routings on the back of the rack for the Arp Switcher Combinator

Where do I go from here?

Using this method you can switch between any two CV sources going to the same destination CV input. So let your mind wander and try it out using a Scream or RV7000 or any filter envelope. Anywhere you use CV, this method hopefully inspires you to try playing around with CV and using it more creatively when working on your songs.

Did you find this tutorial useful or beneficial? Let me know. And as always, if you have other ideas related to CV switching, please share them with all of us.

We don’t live in a vacuum (well maybe sometimes we do, however, for the most part we learn by experimenting with many different elements from different sources) and so this tutorial will build upon a previous tutorial on using Thor’s CV capabilities to switch between 2 different CV sources. In addition, there will be a new element which shows how the Auto CV on the back of the Scream can be used to follow the audio from a Dr. Rex. And this is really the heart of the tutorial.

The “Auto CV” feature on the back of the Scream device is an envelope follower with a twist. While most envelope followers work on Audio and in essence shape the parameters of the audio, the Scream’s envelope follower follows the audio, and then converts that to a CV signal. Before Reason 4, this was the only way you could essentially create a CV signal from an audio source. With the advent of Reason 4, you can use Thor to perform the same functions. Even so, it’s worthwhile to note how the Auto CV works in the scream, as it can still be used effectively, with the added bonus that it leaves a lighter CPU footprint, and allows you access to the Scream as an FX insert as well. Finally, I’ll touch upon how you can achieve a similar effect using Thor.

The project files can be downloaded here: auto-cv-chasing-audio It contains three Combinators which are used as examples to show the Auto CV setups described below. A matrix is used to play a random pattern so you can hear the results. All Combinators play simultaneously through the main mixer, so don’t forget to mute or unmute the channels to hear the proper example.

Using the Scream Auto CV to convert Audio into CV

Create a Combinator and a 6:2 Line Mixer. Then holding shift down, create in order a Thor, NN-XT, Scream and Dr.Rex device.
Click the Show Programmer button in Thor, and turn off Oscillator 1, Bypass Filter 1, and click the “1” button next to the Filter 1 slot. Add a Low Pass Ladder Filter in the Filter 3 slot. Finally, click the Delay button to turn on the Global Delay.
In the NN-XT open up the patch browser and navigate to the Factory Soundbank. Go to the NN-XT Sampler Patches > Synth Poly and open the Odd Poly patch.
In the Scream device, turn off the “Damage” parameter.
In the Dr.Rex device, open the Patch browser and in the Factory Soundbank, nagivate to Dr Rex Drum Loops and load the Hse40_RideBeat_130)eLAB.rx2 patch.

The Front of the Rack with all Devices necessary to chase your audio

We’re done with the front panel. Flip to the back of the rack, and let’s move on to routings. First, route the NN-XT’s 1/L and 2/R to the Audio In 1 and Audio In 2 on the Thor Audio Inputs, respectively. Then route the 1 Mono/Left and 2 Right from the Thor’s audio outputs to Channel 1 on the Line Mixer (left and Right, respectively). This sets up the audio to be heard. Now comes the Auto CV magic.
In order for Auto CV to work, the Scream needs to have a sound source fed into it. So connect the Dr.Rex L & R audio outputs into the Scream Audio Inputs (L and R, respectively). Then connect the Auto CV output from the Scream unit into the CV 1 Modulation input on Thor.

Auto CV routing to follow the Rex Audio file via CV

Flip the rack around and let’s set up the Thor Modulation Bus Routing Section (MBRS). Enter the following parameters on the left side of the bus:
CV In 1: 66 > DelFBack

CV In 1: 66 > Del ModAmt

Enter the following parameters on the right side of the bus (just to keep things simple for now):

Audio In1: 100 > Filt3 L.In

Audio In2: 100 > Filt3 R.In

With this setup, the Auto CV is affecting the Thor Delay Feedback and Delay Modulation Amount. To hear what the Scream is actually doing, we can set up a Combinator switch on button 1. So click the Show Programmer button on the Combinator, and click the Thor in the Device section of the programmer. Enter the following two lines in the Modulation Routing section:
Button 1 > Mod 1 Dest Amount: 0 / 66

Button 1 > Mod 2 Dest Amount: 0 / 66

Programmer Modulation Routing in the Combinator
Now set up a Matrix to play a simple pattern using the Combinator. Turn Button 1 on to hear the Auto CV affecting the Delay. Turn it off to hear the unaffected Delay. Note that you need to have the Dr. Rex receive notes in order to have it send audio into the Scream device. By setting up the Matrix to sequence the combinator, the matrix ends up playing the Dr. Rex. So you’re all set. Alternately, if you don’t want the matrix sequencing the Combinator, you can always copy the Rex notes to its sequencer track so that the Dr. Rex is played via the main sequencer. The point is, the Dr. Rex needs to be active.

What’s happening is the Dr.Rex loop is converted to CV, and this CV is used to affect the Thor Delay. It’s a simple but powerful setup. And you don’t have to limit yourself to affect Thor parameters. I only used this as an example. You run any audio source through the Scream and then use the Auto CV to affect any other CV parameter. Also, since the Scream is not generating any audio output, it doesn’t affect the mix in any other way than a simple CV conversion (or more technically, a CV envelope follower).

Switching CV sources

Not to be one to leave well enough alone, here’s a way to extend the Auto CV idea above and have the ability to switch between two different Rex Files (2 CV sources) using the Thor. The parameters affected are the same (Delay Feedback and Delay Modulation Amount), but the Rex file used to affect the delay can be switched. Here’s how you do it:

Building upon the above example, at the bottom of the Combinator stack, holding Shift down, let’s add another Scream and Dr. Rex.
Next, turn off the Damage parameter in the second Scream. Also, add a different loop into the second Dr.Rex device.

The front panel with two scream and 2 Dr. Rex devices

Flip the rack to the back, and send the Audio from the Second Dr.Rex to the Second Scream, and send the Auto CV output from the second Scream to the CV 2 Modulation input on the Thor.
Now we’ll have to set up Thor to also accept the second Dr.Rex CV source. In the MBRS section, enter the following:
CV In 2: 66 > DelFBack

CV In 2: 66 > Del ModAmt

Finally we need to use the Combinator button 1 as a switcher between the two CV sources. So in the Combinator’s Modulation Routing section, enter the following:
Button 1 > Mod 1 Dest Amount: 66 / 0

Button 1 > Mod 2 Dest Amount: 66 / 0

Button 1 > Mod 3 Dest Amount: 0 / 66

Button 1 > Mod 4 Dest Amount: 0 / 66

Programming the Modulation Routings in the Combinator

With this setup, Button 1 on the Combinator is used to switch between the 2 Scream CV sources (which in turn comes from the two Dr.Rex devices). Leaving button 1 off uses the first Scream device. Turning the button on turns off the first Scream CV source, and turns on the second Scream CV source. Note: it’s not actually the Scream that is turning off. We’re just bringing the amounts down to zero on the Thor programmer panel, which has the same effect.

It should also be noted that you can program a Rotary on the Combinator to cross-fade between the two CV sources, if you wish to have a fading effect between the two. Where you take this idea is really up to you.

Using Thor as an Audio/CV converter

Let’s say you don’t want to use the Scream, and instead want to use Thor as a “Auto CV output” or CV envelope follower. Here’s how you set that up.

Starting from scratch, Create a Combinator and a 6:2 Line Mixer. Then holding shift down, create in order a Thor, NN-XT, and Dr.Rex device.
Click the Show Programmer button in Thor, and turn off Oscillator 1, Bypass Filter 1, and click the “1” button next to the Filter 1 slot. Add a Low Pass Ladder Filter in the Filter 3 slot. Finally, click the Delay button to turn on the Global Delay.
In the NN-XT open up the patch browser and navigate to the Factory Soundbank. Go to the NN-XT Sampler Patches > Synth Poly and open the Odd Poly patch.
In the Dr.Rex device, open the Patch browser and in the Factory Soundbank, nagivate to Dr Rex Drum Loops and load the Hse40_RideBeat_130)eLAB.rx2 patch.
We’re done with the front panel. Flip to the back of the rack, and let’s move on to routings. First, route the NN-XT’s 1/L and 2/R to the Audio In 1 and Audio In 2 on the Thor Audio Inputs, respectively. Then route the 1 Mono/Left and 2 Right from the Thor’s audio outputs to Channel 1 on the Line Mixer (left and Right, respectively).
This time, connect the Dr.Rex L & R audio outputs into Thor’s Audio Inputs (3 and 4, respectively). Then connect the CV 1 output to the CV 1 Modulation input, both input and output are on Thor, so yes you can route a CV out on Thor to a CV in on the same Thor.

The back of the rack - routing Thor to work as an Auto CV envelope follower

Flip the rack around and let’s set up the Thor Modulation Bus Routing Section (MBRS). Enter the following parameters on the left side of the bus:
CV In 1: 66 > DelFBack

CV In 1: 66 > Del ModAmt

Enter the following parameters on the right side of the bus:

Audio In1: 100 > Filt3 L.In

Audio In2: 100 > Filt3 R.In

Audio In3: 100 > CV Out1

Audio In4: 100 > CV Out1

The MBRS settings in Thor

With this setup, the Auto CV is contained within Thor. The Thor is using the Audio from the Dr.Rex directly, and then converting the Audio source into a CV signal which is then sent back into Thor to affect the Delay Feedback and Delay Modulation Amount.

One note here: if you test out the sounds from the Thor CV setup versus the Scream CV setup, you’ll notice that the Thor CV is much smoother. I’m not sure why that is. It may be a difference in the way I’ve routed things, or a difference in how the Scream handles the Auto CV output feature. But there is definitely a difference in sound. Of course this could be pilot error and I may not have the connections set up correctly. I admit my mistakes all the time. But at least it gets you pretty close.

So any other ideas you have for using the Auto CV output on the Scream device or setting up Thor to convert an Audio signal into a CV signal? This is a very basic example, but it opens up a lot of potential with other sound sources / CV destinations. For example, if you have a CV destination that you want to track to the lead vocals in a song, you can do it easily. So what other possibilities are out there?

Tag: CV Switching

20 – CV Switching