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In-Depth with Reason 4’s Matrix Pattern Sequencer

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Read Time: 13 min

The Matrix Pattern Sequencer is a valuable tool in Reason 4’s plethora of rack devices. It makes no sound of its own—its power lies in its ability to control other devices. If your sound device can receive CV data, the Matrix can make it do all sorts of cool things from the obvious choice of note sequencing, to controlling oscillators and filters.

What Does the Matrix Pattern Sequencer Do?

The Matrix Pattern Sequencer allows you to enter note, velocity and curve data and outputs that data to the CV inputs on other devices of your choice. There are three different types of data output: Note CV, intended for controlling note pitch data but useful for other things, Gate CV, for conveying timing and velocity data, and Curve CV which is useful for controlling synthesizer parameters such as oscillators, filters and so on. Curve CV can be used in unipolar or bipolar modes, which we’ll look at later.

Device Overview

Before we dive into setting up and actually using the Matrix, let’s briefly cover the front panel of the device so you know what to expect, and in which general direction to look for buttons I might mention later on.

  1. On the left side we have the pattern bank controls. These allow you to switch between patterns, and preview them.
  2. In the middle is the sequencer, where you can draw in any sort of data the device supports.
  3. On the right are controls pertaining to the length and tempo of each pattern (they do not effect individual notes at all).

The back panel of the Matrix is one of the most simple back panels you’ll find in the program. There are three outputs and one switch. You route the outputs to the devices you wish to control and the switch controls the type of Curve CV data you can enter.

Setting Up Your Project

Open up a new project and create a sound device. I’m going to create a Subtractor, and for the purposes of this tutorial it’s probably better for you to do so too — however, I’ll explain things so that you understand the principles and don’t necessarily need to follow every step I make.

Right-click on the Subtractor and head for the Create submenu. Right near the bottom you’ll find the Matrix Pattern Sequencer — click on this option to create one. Unless you prevent it or do something wrong, Reason will auto-route the Matrix to the selected sound device. Press Tab to flick the rack around and have a look. In case you wish to route manually, or it routes to the wrong device (which will happen if you create the device with no sound device selected), you need to connect the Note CV output of the Matrix to the CV input of the sound device, and the Gate CV output of the Matrix to the Gate input of the sound device.

The Curve CV output is situational, so leave it unattached for now and we’ll discuss it later. Ideally, you’re back panel should currently look like this:

Flip Reason’s rack back around by pressing Tab.

Output Types

Earlier I mentioned the three output types of the Matrix device and now I’m going to show you where to edit these types of data in the device, and in the next section we’ll start looking at how to edit them.

Note and gate data is shown by default when you create a new Matrix device. In the sequencer area, there’s a switch that toggles between Keys and Curve. This data is shown when the switch is toggled to Keys.

Unless you’re doing something unusual, note and gate data are used in tandem. The note data determines the pitch and start location of the sound, while the gate determines whether a note position is on or off, what its level is (and can be used for a pseudo-velocity control), and whether it is tied to the next note — in other words determining whether there’s an evident break between notes or not.

If you toggle the switch from Keys to Curve, you’ll see the Curve editor. You can click and drag to draw in a pattern, which you’ll want to do in most cases for the most natural result, or you can click to set the value of each individual step. This data is used to control just about anything, but most often variable synthesizer settings. For a bit of fun you can always hook the Curve CV up to the sound device’s CV instead of the Note CV output.

Creating Patterns

At this stage we’re still looking at a blank Matrix sequencer, albeit a correctly routed one! By default, you’ll notice that the Matrix has some basic gate information—full “on” position for every step, so that you can get started quickly.

Note that if you clear the pattern, that default gate data will disappear — don’t panic thinking that your device is broken because it’s not making any noise!

The note data, however, is blank. You can’t edit the length of these steps, so think of entering data here as being much like Reason’s main step sequencer with less options. Click in a space in the grid to set that’s steps pitch to that location.

Although the step sequencer shows 32 steps, by default the pattern length is 16. If you want more or left you can change this number using the Steps setting on the right side of the device. Leave it at 16 for now.

Experiment with drawing in a pattern, though be careful not to waste your time filling in notes past the 16th step. You can tell how may steps are included in the pattern by the dark red line at the very top of the sequencer.

I’ve gone ahead and created a simple pattern of my own:

You can preview your pattern by pressing the Run button in the pattern selection area. To listen to mine, press the button below:

If you’re notation is failing you at this point, feel free to copy mine from the image above (not that it’s anything special!). Now you’ll have set your notes, but the pattern feels boring and monotonous. That’s where our gate data comes in.

Gate Toggle & Level

Each of the vertical red lines underneath the note data represents one note’s worth of gate data. If you can see any red, no matter how tall, it’s On — to turn that note off so you have a rest instead of audio playing, click on the red line and drag it down until you see nothing. To change the level, drag it the same way, even if you can only see a tiny bit of the red line. It’s still set to play that note.

You can play with the level like a sort of fake velocity — it’ll work well enough for our purposes.

I’ve dragged the repeating C notes down, with the exception of the starting note, so that they’re more reinforcing notes than part of the main melody. I’ve also removed a note by turning its gate data off to give a little more rhythmic movement. The level is not particularly sensitive, so I’ve turned it down as much as possible without turning it off.

Here’s what I’ve got now:

It’s slightly more interesting than before. There’s a third setting we can use for artistic effect or just to have more control over note lengths, and that’s the Tie feature.

Tied Notes

There are two ways to create tied notes: you can click the “Tie” button to the left of the sequencer to make all steps you click on in the gate data area into tied notes. The much easier way is to hold Shift and click on the step — you don’t want to be going back and forth between the toggle button every time you want to create a tied note.

You can tell a tied note by the doubled width of the gate. As you can see in this screenshot I’ve created five tied notes for a total of three audible tied events:

There’s a single note at the start that I’ve turned into a tied note so that this particular note sounds slightly longer, but doesn’t tie into the next note. A few steps down, I’ve made two notes (one with a high level and one with a low level) into adjacent tied notes, which means they act as one unbroken note and pitch slides as it would if you had very precise pitch bend skills.

A few more steps down from that and two of the C notes with low-levels have been tied. When you tie two notes of the same pitch together, it creates one double-length note. This is the only way you can control note length in the Matrix Pattern Sequencer.

Here’s what the tied notes sound like — listen out for all three instances:


By this stage you may have noticed that you’ve been restricted to a single octave this whole time! As the Matrix is a purely monophonic step sequencer, you may not need to use more than one octave in a single pattern very often, but the option is there.

To navigate between octaves you’ll find a switch to the left of the sequencer, below the Curve/Keys toggler. It’s labeled from 1 to 5, with 1 being the lowest octave and 5 being the highest. By default, you’re on the third octave.

Simply move the switch to edit notes on other octaves. For this example, let’s change our C notes into bass notes.


If you need to create patterns that are longer or shorter, the Steps setting to the right will allow you to change the length to between 1 and 32 steps. If I set it to 32 steps, you can see the red line that extends halfway across the sequencer in previous screenshots now extends to the end of the sequencer:


Resolution allows you to change the speed at which the pattern is played, by essentially changing the length of each step. This way the Matrix is, at all times, in sync with the project’s tempo, while giving you control over the relative speed of your patterns.

So far I’ve had the Matrix on 1/8T, but the default is 1/16. This is what our pattern would sound like at the default resolution:


Below the resolution is the Shuffle toggle. Shuffle gives the pattern a “swing” feel by delaying sixteenth notes that fall between the eighth notes.

You can adjust the amount of shuffle by clicking on the ReGroove Mixer button in Reason’s transport bar and adjusting the Global Shuffle knob — although this will effect all devices with Shuffle enabled.

Modifying Variables with Curve CV

Let’s take a look at what we can do with Curve. Flip the toggle over from Keys to Curve in the sequencer section and you should see a blank sequencer with a grid like the Keys grid, minus the horizontal lines.

Press Tab to flip the rack around and have a look at the back of your sound device. I’m using the Subtractor so there are plenty of things I can control with CV. Everything under the Modulation Inputs will work, among other things. In this case, I’ll connect the Curve CV output to the Subtractor’s Filter 1 Freq.

Let’s flip the rack over again. I’m going to draw in a staged pattern so you can hear the differences between each level of data change more clearly:

Have a listen to the audio. It starts off with the clean sound from earlier, gets a bit grungier in the middle, and even more distorted towards the end:

You can control all sorts of things this way. I’ve switched the routing so that our curve now controls the Pitch Wheel:

Unipolar Versus Bipolar

So far, we’ve been working with the Curve data in unipolar mode. This means that the data starts at 0 and goes up from there in one direction — when you’re sending Curve CV, you’re adding to whatever data is already there in the sound device, but never subtracting from it. This means that when you’re sending data to something like the Pitch Wheel with unipolar curve CV, the pitch will only ever be “wheeled” upwards. As you probably know, though, real pitch wheels on real keyboards go upwards and downwards. It’s more realistic if we set the Matrix to bipolar, which allows us to move variables both up and down.

Press Tab to flip around the back and change the setting to Bipolar and then come back around to the front of the rack. Instead of a graph with a baseline at the bottom of the sequencer, the baseline is now in the center and we can move the bars both up and down:

I’ve drawn in a diagonal line that goes from the maximum negative level to the maximum positive level. Here’s the difference in sound while the Curve CV remains routed to the Pitch Wheel modulation input:

CV Input Sensitivity

Most sound devices will allow you to set the sensitivity of CV inputs. This is the case with the Subtractor which has the sensitivity pots on the left of the inputs:

Changing this basically changes how much the CV data will effect the sound device’s variables. If I turn the Pitch Wheel up to maximum, here’s the difference in sound:

It’s a more pronounced change because the CV data is allowed to swing the Pitch Wheel further in each direction.

Selecting & Storing Patterns

What happens when you’ve created a pattern but you want to create another one without erasing the current one?

The Matrix has pattern storage for 32 patterns, with 4 banks that hold 8 patterns each.

Simply select the bank you wish to store your new pattern in from the four options (A, B, C, and D) and then the pattern number you wish to store it from by clicking on any number from 1 to 8. Be careful to remember which bank you’re using so you don’t find yourself wondering why your pattern has suddenly “disappeared” later on!

Copy Pattern to Track

There are a bunch of features you can access by right-clicking on the device. Most of these are self-explanatory: the Shift Pattern options move the pattern one step in whichever direction you’ve chosen, Randomize Pattern simply creates a random slew of notes and gates that usually don’t sound useful at all, and Alter Pattern creates a random pattern with the notes you’ve already used — if you draw in a scale you can get pretty decent results with this one.

Probably the most useful of these options is the Copy Pattern to Track option which appears on many Reason pattern devices, such as the Redrum unit and Dr.REX Loop Player. This takes your current pattern and copies it to the sequencer track between the designated Left and Right points.

This feature makes it possible to edit your patterns with Reason’s standard sequencer, and line up different patterns on a track as much as you want in the sequencer window. These patterns, once on the track, play directly through the sound device connected to the track the clip is placed on, independently of the Matrix device itself.

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