Getting a subwoofer to work from a stereo source


Standard Member
I have a Marantz SR5013 AV amp and Polk PSW 110 subwoofer (along with other speakers set to 'small' which are irrelevent I hope to this discussion).

It's the problem of getting bass to the subwoofer when playing a stereo source. I've read many articles and posts relating to this and I'm just setting down my thoughts, as although I have it working, it may not be the only or best method.

On the amp, I've selected 'stereo' as the format and under Audio/Surround Parameter "Subwoofer" is ON. The sound card from the PC is the stereo source input into the amp.

With the subwoofer set to LFE, I have to increase the offset from zero to +8db (min) to get any output from it and that's with it's own volume wound right up.

With the sub set to LFE+main, I still have to increase the db level but don't have to turn up the volume on the sub as much. This is expected because more bass is going into the sub.

Is this what you would expect and if so is it OK to up the sub's db's on the amp and crank up the volume on the sub to it's max, or is there a better/proper solution ??

Many thanks.


Distinguished Member
If your front left and right speakers are set as SMALL then the AV receiver will convey all frequencies at and below the associated crossover away from the left and right speakers and out to your active sub (via the sub pre out). THe sub obviously needs to be part of the setup and you'd not even get the option of designating the front left an right speakers as being small in the absence of an active sub.

It has to be noted that the AV receiver bypasses all bass management if its PURE DIRECT mode is engaged. The front speakers would be regarded as LARGE/FULL RANGE in such instances In such instances and only duscrete LFE channel audio would be sent to the sub. Stereo 2 channel audio has no discrete LFE channel.

It is ordinarilly suggested not to set the sub as LFE+MAIN. THis setting duplicated the low end frequencies via both the sub and the speakers and can give rise to issues with bass boom.

I'd maybe suggest that the setup you have is working as intended, but the resuklting audio is not to you liking or not adhering to your expectations?

After running the calibration, fo not alter the sub's volume using the volume control on its rear. Adjust the output of the sub according to you prederences via the adjustment available to your via the OPTION menu.

Prior to even running the calibration you should have set up the sub's own controls as follows:

  • Volume to about 10 o'clock and no hiogher than mideway
  • Phase set to 0°
  • THe frequency filter set to its highest setting or a dedicated LFE option if it has one

Post calibration, set all speakers as being SMALL and set the associated crossovers no lower than 80Hz.

Maybe also worth you investigating the location of the sub prior to then calibrating it? You could be sat in a null were lower end frequencies cannot be heard? Moving the sub could potentially resolve this?

Try placing the sub where you'd ordinatlly be while listening to your setup and then move around the room until the bass starts to sound better. Where you heard the imptovement is where the sub would be better placed.

If you still feel the need to enhance the sub's output, do so via the settings in the OPTION menu. You can even have different OPTIONS relative to different sources. I'd not suggest you mess with the settings on the reverse of the sub itself post calibration though. The only exception to this would be relative to the phase setting. You could try setting this to 180° after the calibration in order to reverse the polarity of the sub. Now listen to determine whether this resulted in an improvement?
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