Sonos Amp and 3rd party subwoofer issue

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I am having issues connecting my Sonos Amp (Black) to my Klipsch SW-311 10-Inch Subwoofer (or vice-versa). I currently have two Klipsch speakers and the Klipsch Subwoofer connected to the Sonos Amp. Both speakers play but I am getting no sound from the subwoofer. The subwoofer is connected to the sub port on the Sonos Amp and the LFE port on the sub. The sub plays when connected to my Yamaha system but doesn't play when connected to the Sonos Amp.

Is my sub's connection wrong? Will a sub with a built-in amp not work with the Sonos Amp? What am I doing wrong?

Help please...


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121 replies

Hey there, jale01. While attempting to play audio to the Klipsch subwoofer, please submit a diagnostic report and reply here with the confirmation number. I'll be happy to take a closer look and point you in the right direction. The Sub Out of the back of the Amp is line level so it should work with no problem when plugged into the LFE port.
I am having the same issue with my infinity subwoofer.
Perhaps following the suggestion in the post previous to yours might be a first step?
Userlevel 1
Hi Keith N,

Thanks a lot for reaching out.

Here's the diagnostics confirmation number: 954397645
I am having the same issue with my SA subwoofer.
I’d still recommend following the suggestion made by Keith a few posts above yours.
Userlevel 1
Same issue here, new Sonos amp, connected 3rd party sub to the sub out but no joy. The sub works if I provide signal from another source.
I can submit diagnostics but looks like people having done that earlier in this thread have had no response......
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Just sent my diags. # 851627850
Userlevel 7
Badge +20
Just to check the obvious: I assume you have enabled the sub output:
Settings > Room Settings > [Room Name] > Advanced Audio > Sub Settings > Sub.
Thanks PWT,
I have a similar issue (only recent, subwoofer worked well for years) with an Amp and a correctly wired subwoofer in a 2.1 configuration. Subwoofer is working fine on alternative sources.The signal from the Sonos amp has become "weak" to non-existing. The cable is ok, the amplifier from the sub is ok. The issue seems to be inside the Sonos Amp.
Funny enough, my Sonos controller on my Android phone doesn't offer me the option of "Sub Settings". My other Sonos controllers don't even have advanced setting anymore.
Dear Keith here comes my diagnostics number. The issue is in "Esszimmer".
Looking forward to read from you,
Cheers, Emile
I have the same issue with a SVS PB12 Plus/2 sub out from Sonos Amp does not play. The sub works fine on other sources, ive called Sonos support but they could not fix it after having looked at logs..... Might have to return the Sonos amp, which is sad, cause it seems like something that could be fixed.
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We have the same problem - A well working powerful sub (Bowers & Wilkins) that recieces no signal from the AMP Sub-out, no matter what we do. I see in that the discussion here is up to 5 months old and there is still no explanation on how to fix it. Keith - have you posted a solution somewhere else?

Please advice us. I do not want to hand the AMP back but will if it does not work as intended.

Just to be clear, you're not using the Sonos Amp to power surround speakers, are you?
Userlevel 1
Just to be clear, you're not using the Sonos Amp to power surround speakers, are you?
We have tried both, surround on and off - no difference with respect to the Sub out signal.

It seems obvious from the preceeding discussions above the many have the same problem. I expect Sonos to come up with a solution well within the 5 months that this problem has been known.
I don't work for Sonos, so I can't give you any insight into whether this is an issue or not. I do know that when the Sonos Amp is set up as powering surround speakers, the subwoofer out is turned off, since the only signal being sent to the Amp is the surround signal, and not any of the additional LFE signal.

Have you submitted a diagnostic, and contacted Sonos support, or are you just posting anecdotal data here on the boards?
Userlevel 1
I do not see the point with submitting yet another diagnostic of the same problem. Several have already done that, without any solution posted so far.
It’s the contact with Sonos support that is the solution. Posting here on a community board doesn’t really further the data about the issue. If Sonos can’t see and reproduce the issue, all the “me too’s” in the world won’t help. Give them concrete data, and call in to discuss it.
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Badge +22
Calling is best but you'll at least get your diagnostic looked at if you use one of the 24x7 support options or even e-mail. These boards do little to help the Sonos tech that visit from time to time find posted diagnostics and even then there is often too little data to do anything with them.

See the Contact page and make sure it is set to your country and then pick an option.
Similar problem, I have an almost brand new Sonos Amp.
B&W speakers.
Paradigm Seismic 110 Subwoofer (10") rated at 1,700 watts Dynamic Peak / 850 watts RMS Sustained

I have enabled the sub output:
Settings > Room Settings > [Room Name] > Advanced Audio > Sub Settings > Sub
See screen print

I am getting a very weak signal.
If I leave the "Sub Level" in the middle, the sub trigger does not even recognise the signal (photo 1)
I have to turn up the signal a long way (almost to the right) to get a signal to the subwoofer (photo 2)

Photo 1

Photo 2

Sonos Diagnostics is submitted today is 1031694162.
I've been using a Sonos Connect Amp to power in ceiling speakers and a Martin Logan Abyss subwoofer in our master bedroom for years. Swapped it out for the Sonos Amp as I'd like to use the Connect amp for another set of speakers. After hooking it up and playing the same music/sources, the subwoofer is severely lacking. I checked the sonos settings and the sub is enabled. I adjusted the crossover and have the sub level in the middle, sometimes the sub won't even come out of standby. I used to keep the subwoofer set to level 3 and the Connect Amp sub setting in the middle and it was plenty of bass. Now I have the subwoofer level set to half volume and the sonos sub setting almost all the way up and it still doesn't seem to produce the equivalent amount of bass. No other changes have been made. I'm contacting support now to see if they have any input on this. I'm pretty disappointed so far.
Just bought a Sonos Amp today. I have the same problem as other recent posts. The Sub output is too weak, even at max volume and highest crossover setting. This output needs to be recalibrated. Sonos should err on the “hot” side, as the output can be adjusted on the the connected 3rd party sub. A hotter signal would also improve the signal to noise ratio.

If anyone at Sonos can address this ... I thank you in advance. C’mon bruh, I want some BASS!!!!
Just to update everyone. I was on the phone with support who took over an hour to understand what I was asking and tbh, at the end of call really didn't address my issue. They wanted me to hook up the sub to my old connect amp and switch back and forth between that and the Sonos Amp while playing the same source to see if there was a volume difference. There is, which I stated within 1 minute of the beginning of the phone call. She put me on hold a few times and basically told me I need to contact the manufacturer of the subwoofer and ask them about level adjustment. It's not their product that is the problem, it's the Sonos Amp. She was also asking me to make level and XO adjustments on the old connect amp. Ummmm, it doesn't have seperate subwoofer adjustments like the Sonos Amp does. Anyone know how to skip the flow chart readers and get to a support agent that is knowledgeable about the product they are supposed to support?
I had the same problem as everyone else her.
I had to set the settings in the sonos app all the way up, and use the "force on" setting on the subwoofer.

Works nicely now. 🙂👌

Userlevel 2
I am about to purchase an SVS sub to replace my Sonos Sub for my Sonos Amp 2.1 set up. Has this issue been resolved?
I have the same issue. Sub turned on in app set to maximum output level and it is barely audible. My sub only has an LFE input and no level adjustment, it is line level and relies on the source. The Amp sub output is way to low and does match the L and R line level, not even close. This is manufacturing defect and will hopefully be acknowledged and fixed in a firmware update very soon. I am shocked that the Amp has been out for months already and this has not been addressed.
This is an obvious known issue that is being widely reported here and really, all over the Internet, just search Sonos. Trying to troubleshoot and fix one customer at a time is not the right approach.
My return window just started, but I hope you take this seriously and get the engineers involved right away. Not sure how this ever made it out if the factory, let alone not already rectified after being widely reported.