Sonos Amp and 3rd party subwoofer issue.

  • 11 February 2019
  • 31 replies
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31 replies

I have the same issue and reported it to Sonos. My setup includes two Q Acoustics 3020 bookshelf speakers, a Pioneer SW-8MK2, and an HDMI connection to my TV. I got the following troubleshooting steps from a Sonos engineer:

1) Connect your Subwoofer to the Sonos Amp.
2) Disconnect your bookshelf speakers from the Amp (please disconnect the speakers from the Amp side by removing the speaker wire adapter).
3) Now test playback with only the Subwoofer. Does this work properly?
4) Regardless of the result, please submit a diagnostics while it is playing in this mode.
5) Next, re-attach only the speaker adapters to the Amp but without the speaker wires. You should effectively only have the Sub and adapters plugged.
6) Once again, please test playback and provide a second diagnostics.
7) Lastly, re-attach the speaker wires to the adapters and test one more time along with submitting a diagnostics after completing the test


Unfortunately, I received these tips after I returned my subwoofer (Sonos was taking a while to get back to me, and this thread didn't leave me with much hope that this issue would be resolved). The bookshelf speakers are serving me fine for the time being, but here's to hoping that the steps above will help someone else with this issue.
Those steps appear to be a test to ensure the subwoofer output is working at all. I think everyone with the issue can confirm the sub out is working, just at a greatly reduced level from what the speakers are outputting (easy fix in firmware for them, just increase the starting sub output level)
I can't believe their engineers can't pull one off the shelf and test this, it would literally take two minutes. Maybe they don't have a 3rd party sub and have only used the Sonos sub, which connects differently and I'm sure works perfectly.

Can anyone suggest an alternative box that provides the same functionality and similar power? Will have to replace the Sonos Amp if they won't address this. I replaced my Pioneer XC-HM86 with the Sonos Amp. The only thing that was lacking was power, otherwise a great device and even has a color display screen.

I am having the same issue. I have a sonos amp connected to two standard stereo speakers and a wrs subwoofer. No sound coming out of the sub...

I am having the same issue with a Sonos Amp and a third party sub. I have started the tech support route, but am not encouraged.

Has anyone made headway on this issue? Or does anyone know the target specs on the LFE output signal amplitude? For most amplifiers this number can be dug up, but I can’t find it anywhere online. All I find is “Auto-detecting RCA type, adjustable crossover” which isn’t helpful.

This seems to be a problem affecting many users. I’d like to know if there is a batch of faulty amps, or their target spec for this output is way too low.

If the target spec is low, this would violate the spirit of their manual, which states, “Connect a powered subwoofer to this output using a standard RCA cable. The system will detect when a cable is connected to the subwoofer output and adjust the crossover frequency automatically.” as RCAs typically carry line-level signals, which have a fairly agreed-upon amplitude.

I had the same problem when I got my amp and connected my subwoofer with a simple rca cable: the sub output was very low and I had to crank up the sub level in the Sonos app. Everything was fine after I switched to a y-cable (1-male to 2-male), now connecting both (L+R) inputs of my sub. These cables are available for around $10. Maybe worth a try...

I had the same problem when I got my amp and connected my subwoofer with a simple rca cable: the sub output was very low and I had to crank up the sub level in the Sonos app. Everything was fine after I switched to a y-cable (1-male to 2-male), now connecting both (L+R) inputs of my sub. These cables are available for around $10. Maybe worth a try...

 Can anyone confirm this resolves the issue? This would seem to a ridiculous oversight by Sonos if true.  

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