If you have a digital mixer, you may be wondering, what is the best use of a matrix?
An audio matrix should be used anytime you need to create a slight variation of your main mix, like setting a crossover for your mains and subs.
What is a crossover?
An audio crossover is basically an EQ filter that enables you to split up an audio signal into two or more frequency ranges.
In other words, with a crossover in place, you can send only the low frequencies to your subs and everything else to your mains.
Modern powered speakers and amps will often have built-in crossovers. For example, on the JBL SRX828SP, you can use the little display on the back to program a crossover at 60Hz, 80Hz, 100Hz or even connect it to your network to select a custom crossover setting.
If your speakers don’t have this capability, or you simply want to program it all from your mixer, an audio matrix is a great solution.
How to Set Up a Matrix Crossover on the X32
Although these are instructions for the Behringer X32, if your digital mixer supports matrix mixes, this should also translate to your mixer.
Step 1: Assign at least three matrix mixes to their respective outputs.
You will need to use at least three matrix mixes: Main L, Main R and Subwoofer. If desired, you can use four matrix mixes for a Sub L and Sub R.
On the X32, navigate to the routing screen and select the out 1-16 tab.
Find the output you are currently using for Main L (most likely Output 15). Set the ‘Output Signal’ to Matrix 1. Then, find the output you are using for Main R (most likely Output 16). Set the ‘Output Signal to Matrix 2.
Finally, find the output you are using for your sub and assign the ‘Output Signal’ to Matrix 3.
Note: If you are currently using the same output as your mains for the sub, you will need to use an open output and connect your sub accordingly.
Step 2: Link Matrix 1 & 2
Matrix 1 & 2 will be used for Main L and Main R, so they need to be linked as a stereo pair. To do this, select Matrix 1, navigate to the HOME screen and push in the knob labeled ‘Link’.
Step 3: Route the main mix to the matrix mixes.
Navigate to the HOME screen. Press the ‘SELECT’ button above the MAIN mix fader. Navigate to the ‘sends’ tab and bring the level up for 1, 2 & 3 (Matrix 1, 2 & 3) to 0dB.
Step 4: Bring the matrix faders up to 0dB.
Press the ‘MATRIX 1-6’ button and bring up the faders for Matrix 1, 2 & 3 to 0dB. Also, you will want to make sure all three are not muted.
Step 5: Apply a low cut filter to Matrix 1 & 2.
Matrix 1 & 2 are for the main speakers, so you’ll need to cut out the frequencies that go to the subwoofers. To do this, select Matrix 1 and navigate to the EQ screen. Activate EQ by pushing the button labeled ‘Equalizer’. Select your ‘Low’ EQ filter and change the mode to ‘Low Cut’. Set the frequency to 100Hz.
Step 6: Apply a high cut filter to Matrix 3.
Matrix 3 is for the sub(s), so you’ll need to cut out the frequencies that go to your mains. To do this, select Matrix 3 and navigate to the EQ screen. Activate EQ by pushing the button labeled ‘Equalizer’. Select the ‘High’ EQ filter and change the mode to ‘High Cut’. Set the frequency to 100Hz.
Side Note on Frequency Placement
100Hz may or may not be the right frequency placement for your speakers. But, it will most likely be somewhere between 80-120Hz.
If you can’t find crossover documentation for your speakers, experiment between the 80-120Hz range to find what sounds best.
Keep in mind, the low cut filter for your mains and the high cut filter for your sub should have the same frequency setting.
Other Uses for Matrix Mixes
There are several other good uses for matrix mixes. Check out your options in this post: