Custom Filters & Firmware Updates

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Installing a Custom EQ Filter:

To add a custom low-pass filter to your BalancedForce subwoofer:

1. Download the appropriate zipped file to match your main speakers.
2. Unzip and save the custom low-pass file in the root directory of a USB flash drive (a USB flash drive was included with your new subwoofer, but any flash drive 32GB or smaller should work)
3. Insert the flash drive into the USB Input on the back of the subwoofer. The subwoofer will automatically find the file and load the custom low-pass filter.

To assure a successful upload to your subwoofer we recommend having no other files or folders on the flash drive—the subwoofer can only load one file at a time. Please review your subwoofer's manual for more information.

Why do some BalancedForce custom filters have multiple options?

One of the benefits of adding a subwoofer to a speaker system is to relieve your main speakers from having to play low bass. It has long been a common practice for MartinLogan to provide a bass control on our floorstanding speakers. Some early MartinLogan speakers adjusted bass by minus 3dB. More recent models with PoweredForce woofers allow adjustments of plus or minus 10dB.

The woofer sections of MartinLogan speakers are equalized to extend the bass response of their low frequency drivers. This equalization causes power from your external amplifier to be delivered to the woofers. Turning the bass control on the speaker to minus 3dB or minus 10dB (and letting the subwoofer fill in) relieves the load on your external amplifier, delivers more power for the upper bass and midrange, and allows the speakers to play louder. MartinLogan BalancedForce custom filters allow you to experiment and determine which method works best for you—letting the speakers play low bass to their fullest capability or letting the external subwoofer fill in. There is no right answer regarding which option to use. As always, we recommend that you try both options and trust your ears.

Firmware Updates

Updating your Subwoofer's Firmware:

Please note, the subwoofer will load whichever firmware revision is on the connected flash drive—even if the firmware revision on the flash drive is older than what is currently loaded on your subwoofer. The latest version of the firmware is available on this page.

To check which revision your subwoofer currently has installed, press the Custom Low-Pass button and hold it for 3 seconds. The Tone Sweep LED light will blink a number of times that is equal to the current revision number (e.g. two blinks = revision 2 firmware).

Please note, updating the firmware should not erase settings for PBK (Perfect Bass Kit) and the Custom Low-Pass filter. A notice will be posted on our website alongside the firmware download if, for some unforeseen reason, a specific firmware revision must erase these settings—otherwise, these setting should still be in place after a firmware update.

1. Download the latest firmware file for your subwoofer model. Save the firmware file in the root directory of a USB flash drive (a USB flash drive was included with your new subwoofer, but any flash drive 32GB or smaller should work). To assure a successful upload to your subwoofer we recommend having no other files or folders on the flash drive—the subwoofer can only load one file at a time.
2. Unplug the subwoofer from the AC outlet.
3. Insert the flash drive into the USB Input on the back of the subwoofer.
4. Reconnect the subwoofer to the AC outlet. The USB Status LED will continually blink red-green-red-green while the firmware is being updated—this blinking may pause momentarily during the update. Do not remove the flash drive until the LED stops blinking and shows a solid color for at least 5 seconds.

Please review your subwoofer's manual for more information.