Not having this issue on either of my two Arcs. Both are connected via ARC to Vizio TVs using the Sonos cable, the TV’s are being fed by Apple TVs. 

I just updated my whole set (Arc+2 One’s and Sub) to 15.4 and experience less bass output to the sub. I’m not amused because this seems like a dajavu to me. I already had an issue with that like many others and now it’s again after an update that de bass of the subwoofer is affected. What is going on Sonos?!!!

Yes sonos  has had  low volume  along with other  sound  problems for some  time .

When they do a fix update effects  something else ,this is poor  management of quality control that should be addressed  prior  to  release   

All  Sonos customers liked the  product to  buy it and paid good  money for equipment  that should  live  up to what is advertised an not  continued technical problems lasting years .

Please Sonos do  right thing clear  board  of all  your  problems , to maintain your leadership  in this  field  of  Sound  Technology .

Waiting for Mr. Peter Pee review before updates get installed here

My Arc/Sub/300’s all sound worse since the update.  More shallow sounding.  I wish I returned the 300’s as the One’s were just all around better, but I had faith Sonos would get it right and my whole system is now worse since today’s update.  

Sonos are you actually testing this before releasing to the public.  For the money spent, should be flawless and all around better with the 300’s over the One’s.  

Have the same problem with 15.3 and now 15.4; however, I have isolated it to my Era 300’s. If I remove them as surrounds the Arc’s volume returns to normal and sounds great. When I add them back the Arc’s volume is significantly dampened/muted.

I never thought that 15.4 would lower the volume even more than 15.3 did after updating.

Is trueplay required after this update?

Ok, I tried playing the same car and motorcycle chase clip from the intro to John Wick II over and over on 4K Blu-ray switching back and forth between Spanish 5.1 Dolby Digital and English Dolby Atmos and now the Atmos track seems to be performing fine with the new 15.4. I also noticed the image above in my app after doing this test. Odd time to show up. I will continue to monitor and post back if it changes again. Oh and I have not run TruePlay, instead I’m using Peter Pee’s best settings for 15.3 https://www.youtube.com/watch?v=qo2Q06FquTI&t=1s

I have exactly the same problem since 15.3 so this still not solved is 15.4 I guess. Since April 28th talking to Sonos support about this issue. This problem occurred since the release of new Sonos speakers and has effect on certain Sonos subs

Hi everyone, I am new to the community.

I have been a big fan of Sonos since last 3 years. My existing Sonos system consists of a Beam + Sub+ 2 Symfonisk speakers and I have been much pleased with the performance.

Two days back, I bought a new Arc planning to upgrade my Beam. After around 1 hour of troubleshooting I was able to connect Arc to my Sonos S2 app. But I was totally disappointed with the low volume and bass of sub when connected with Arc. I could see significant volume/bass difference between Beam and Arc when connected to Sub. I have now taken Arc out of my config and made the connection back to Beam + Sub. Initially I thought it would be an issue with my new Arc, but after reading these posts, I understood I am not alone and the Sonos updates are the cause of it.

I am now planning to return the Arc.

Previously I had a Beam Gen 2 + Sub Mini + 2 Ones and now I've changed the Beam to an Arc.

If with the Beam I selected a volume around 20-30 now with the Arc I have to select around 40-50.

I feel the volume is lower than before. Could be because of the same issue your area indicating?

I only  have  ARC 2  so can't  relate  to  other  systems .

Still  find  volume  very low ,volume  better what  some when I connect direct to TV not thru  cable  box ,to watch movies or  You Tube 

Some  cable companies reduce  volume  10-15  percent , was  true  on my system had tech from dealer  in did  volume  checks with  cable   on an off  , Sonos  just thru TV .

That  said  TV  volume  15  alone  .with Sonos Arc 2 to get same had to  go to  38-40  with Cable  Box connected  52-55 .

Shows  effect  of  cable box , Also shows overall  SONOS ARC 2 low  VOLUME overall .

Most  cases  seen  to  have  similar problem when they switch to Arc 2 from previous   bar.

SONOS needs to  rectify this issue  to  keep  their quality standards  high   for  all  devices . Many  customers been  putting up  with this  long  time .

Please  define  Problem so we  can all  truly  enjoy our systems to   quality  expected . . 

Skipped 15.3 and 15.4 and waited till Peter pee to give the thumbs up. Now have updated to 15.5 and the sonos arc and subwoofer have lost punch while the bread 300s have remained the same and seem to be over powering the arc and sub. This is nuts.

Welcome to the club! This problem exists since 15.3. Somewhere since 28th April. I have exact the same problem and Sonos is about to replace my ARC to see if that solves the problem. When I connect my Sub to a stereo pair one’s SL’s the sub sounds perfect like before. When i add the ARC to the same set, the sub drops in power. Problem is escalated to 4th line support now and they can’t find the problem.

Great. Will wait till Monday to call them. I'm assuming they had you uninstall and reinstall everything?

Yes, I have been uninstalling, factory resetting, creating different groups etc. Everything. Been busy since April 28th now. The only clear difference was when I made a setup with a stereo pair of One’s together with the Sub. As soon as I add the ARC the sound of the Sub collapses 

Lord,  I can't spend 2 months doing this.  I already spent months dealing with them during the dreaded sub drop outs. 

When you say you have su  issues...are you saying it isn't firing at all or just barely?

I'm having a hard time hearing, but I think the Move I have sounds fine alme, but it also loses its punch when I group it with the rest of the setup I mentioned.

I don't know if it will help, but you can tell them I am experiencing the same issue if they ant to compare diagnostics

sub sounds different without the arc then with the arc. It’s firing but I have set the sub volume to 7+. Before update 15.3 it was 2+, now I have to set it to 7+ for the same experience.

Well I live in the Netherlands, I guess it is the best way you contact Sonos support yourself. And tell them about this topic and the problems of course

So finally my problem since April is solved. Sonos replaced my ARC and SUB. Seems there was a hardware issue which didn’t show up in the diagnostics logs. That’s my point of view! But after the replacement there was a big difference in my sound experience. Everything sounds like before. So in this case a replacement solved my problem. Even with the last FW everything sounds like it was before.