DENON AVR-S540BT with Subwoofer Incompatibility Issues


Novice Member
Hello everyone - new to the forum. Hoping y'all can shed some light on some troubles I'm having with my receiver. I got it new in 2018-2019, for context.

About a year ago, a friend offered me some used Definitive speakers - a Center and a Sub - for free. The Center works fine, but I never could get the Sub to work. I thought it was probably an issue with the Sub, because when I did the microphone test with Setup Assistant, the Denon claimed it could never detect the Sub, regardless of if I put the cable in the Subwoofer port (1) or Pre Out (2).

Now, I just bought a new Monoprice Sub and a brand new cable, and I'm having the exact same issue. Even though my bass is set to LFE+Main, my Fronts are set to Small, and my SW is set to On, I get absolutely nothing to come out of the Sub. It's as though there's absolutely no communication between this brand new Monoprice and the Denon.

Any ideas/troubleshooting tips? If I can't get it figured out, I'll probably have to do some deep digging for service techs in the St. Louis area.

Thank you very much!


Distinguished Member
Ensure that the AV receiver's subwoofer pre out is connected to the mono or LFE input on the sub.

Start by configuring the settings on the rear of the sub as follows:

  • Set the gain or volume to what would equate to about 10 o'clock and no more than mid way
  • Set the phase to 0°
  • Set the frequency filter to its highest setting or to a dedicated LFE option if there is one

Run the AV receiver auto calibration using the supplied mic.

Post calibration, set all speakers as being SMALL and set the crossovers no lower than 80Hz. If the calibration set the crossovers higher than this then do not set them lower than where the AV determined.

Note that it is generally suggested not to set the sub to the LFE + MAIN option and to use just the LFE setting. This is because the LFE + MAIN setting can give rise to bass boom.

There's also a LPF of LFE filter. THis should be left set to its default 120Hz.

If the sub has an auto power option then it may be better to leave this turned off?

You can gently place a finger on the sub's driver while portraying audio to determine whether or not it is active or not.

Also note that bass management will not be in operation if or when you have the AV receiver in its DIRECT mode. THis mode bypasses the speaker size and crossover configurations. THe only output to the sub in this mode will be a discrete LFE channel if present in the audio. This LFE channel is not present within 2 channel stereo audio and would only be included within multichannel sources.
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