Adding a Subwoofer to the CasaTunes CT-12X8 Matrix Amplifier

Written by
David Krinker
September 1, 2020

The new CasaTunes CT-12X8 Matrix Amplifier is CasaTunes’ flagship, high performance matrix amplifier.  Not only does it offer more input sources, rooms, and power, but it also offers many advanced features.  Over the next few weeks, we will be highlighting these.

In CEPro’s 2020 deep dive research into multi-room audio, dealers reported that 32% of their multiroom audio projects included a dedicated subwoofer amp, providing homeowners a superior listening experience, and dealers an additional revenue opportunity.

The CasaTunes CT-12X8 matrix amplifier is designed to address the growing popularity of subwoofers in multi-room audio, by incorporating a low pass filter option, that is available on both pre-amplified zone outputs, which along with changes to CasaSetup, makes adding a powered subwoofer to a house music system a breeze.

How it works

Adding a powered subwoofer requires you dedicate two zones on your matrix amplifier.  The first zone is used for the main left & right speakers in the room, and the second zone, which must be either Zone 7 or 8, is connected to the powered subwoofer.

We configure the zones using CasaSetup.  Select Rooms in CasaSetup, and configure the main room speakers, as usual.  Then select either Zone 7 or 8 (one of the zones with pre-amplified outputs) to use to connect to your powered subwoofer.  

CasaSetup displays two additional options for the zone:

  • Enable Low Pass Filter
  • Select (cutoff) Frequency

There are 4 cutoff frequencies to choose from: 80, 120, 180 or 240 Hz.

Enabling the low pass filter will pass signals with a frequency lower than the selected cutoff frequency and attenuates signals with frequencies higher than the cutoff frequency.


Suppose we want to configure a subwoofer for the Living Room.

Configuring a subwoofer to the CasaTunes CT-12X8 Matrix Amplifier
Low Pass Filter options available for configuring a subwoofer in CasaSetup

First, power off all the zones except the 2 zones we are configuring.  In this example, we named them Living Room Main (for the main living room left & right speakers) and Living Room Sub (for the powered subwoofer).

Select the zone Living Room Sub, check or enable the low pass filter option, and select the desired cutoff frequency, and Save your changes.

Now, using the CasaTunes App, adjust the volume in the Living Room Main and Sub zones to your desire.  

Next, we will record a room group combining the two zones into a single manageable room (group).

Configuring a Room Group to combine the Main and Subwoofer zones in CasaTunes
Create a room group to combine control of the Living Room Main and Subwoofer zones in CasaSetup

Select Room Groups in CasaSetup, make sure the Living Room Main and Sub zones are checked, then select Record room group, and set the Room group Name to Living Room.  

When you record a room group, CasaSetup creates a new room group consisting of all the rooms that are currently powered on and records the volume for each zone, such that any difference in volume between the two zones is maintained as you adjust the room group volume.

Once you have recorded your room group, test it and if necessary, make further adjustments to the volume levels for the two zones.

In the final step, hide the Living Room Main and Living Room Sub zones so the homeowner controls the two zones using the single room (group), thereby simplifying the user experience for the homeowner.