Sonos Amp and 3rd party subwoofer issue

I got a sub working with my system.

I did not make any changes in my Sonos app and system settings except in the EQ to get the amount of low end I wanted. It kicks whether it’s flat or with the EQ boosted five points, which is my preference.   

The one I tried initially, the Sonos Connect Amp was either not pushing enough gain to trip the amp on or the sub was defective. So since my Martin Logan wireless transmitter has a Left and Right input for my Home Theater sub, I pulled out the right that connected to my Sony amp and used that channel for my Sonos Connect amp (subs are mono anyway so left and right in is pointless), and now I use the same sub for both my Sony entertainment system and for my Sonos zone in the kitchen (it’s one big room anyway). Problem solved for me! The ML wireless transmitter is its own preamp anyway so I don’t have to send a stronger signal to kick on the speaker since it’s wireless. 

Your mileage may vary but the bug seems fixed on the latest firmware 11.1.

I had to turn the in-app sub level down from +14 to +2 

Me too!
 

I'm not sure yet if it has fixed the “auto-sleep” issue with my sub. But it's definitely fixed the gain issue! It's very loud now!! I've got from +15 to +3, and may go down further yet!

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.

Thank you for that info.  It seems I am not alone in this and as long as I want to use my own subwoofer I won't be able to in surround config.

 Another possible option the Sonos tech brought up was not to use the surround but rather group the rear speakers and subwoofer and use it this way, but once the surround is implemented the sub”out “ will be automatically disabled.  I don't know if the “grouping” option would work or not, and if would be able to tell the difference but I imagine if it is not in surround set up I am just getting left and right channels split between the Sonos Arc and rear speaker.   What is your view on this?

Thanks.

I’m not sure what you mean by ‘group the rear speakers and subwoofer’. In the Sonos ecosystem, there is a single ‘room’ which contains the front and rear speakers, so there is no way to add a sub to the rears.

Grouping an additional Amp driving an extra subwoofer would be challenging, due to the addition of the 75 ms delay between the Arc’s room and any grouped room.

Essentially, using a third party sub in a sound bar driven room in the Sonos ecosystem is a non starter. In order to use a third party sub, you have to be using the Amp with two third party speakers up front, which allows the sub port to be active, but forces you into a ‘faux’ center channel. 

If you want a sub in a Sonos ‘room’ with an Arc, then the Sonos Sub is the only option. 

Beyond the extra cost, it’s a good performing sub, imho. I’ve got two of them. I’ve considered a third, bonded with a pair of Sonos PLAY:5s, but haven’t pulled that particular trigger yet. 

Is there going to be any valid responses from SONOS in regards to this? I find this type of customer service to be deceptive from a technology company.

I've read that the sub out is only 2 volts (personally I feel it's outdated voltage coming from a car audio guy) , but I would think that is plenty for 90% of the powered subs on the market.

I am looking at purchasing the Sonos Outdoor set with Sonos Amp to start my Sonos journey, but this doesn't appear to be a positive start. I would go to Best Buy and have them connect it all in store, but with Covid closures, that cannot happen anytime soon.

No it is not “just a feature overlooked by Sonos engineers” or a ploy to sell you a Sonos Sub.  It was explained quite plainly why it isn’t possible, it’s because the surrounds only get a surrounds signal from the HT decoding unit.  Otherwise, why would they take the time to make it possible when the Amp is used as front speakers, and not possible when used as surrounds (or even give you a sub output at all)?  

My issue is that the amp sometimes takes a bit to triggger my sub after my sub goes into standby.  Unfortunately my Kef sub doesn’t have a force on feature.  I’m not sure if this is related to the low levels everyone’s talking about.  For instance my children watched a show today and sub wouldn’t kick on.  I switched to Amazon music played a song, finally my sub turned on.  Then I went back and watched the show.  I just increased the sub levels to see if that helps with the triggering.  

Doing research on Sonos Arc with non Sonos rear surrounds and 3rd party sub and came across this thread. So just to clarify, if I have 2 rear surrounds that are non Sonos along with a 3rd party sub connected to the amp, the sub will not work? Does anyone have 2 speakers and a sub connected to the amp to get a surround sound setup with the arc? If I can keep my sub and rear speakers, I’d consider the amp since my current HT setup is decent.