I will try this with my setup (Arc U + 300s + Sub Gen 4 + Sub Gen 3) when I get home, I havent noticed anything but im not a sound engineer.

​@dominiklei  I have the same setup as you and also have the same issue. I have seen many others confirm that they also have the issue on the Reddit channel.

​@Corry P - are you aware of this bug?

Yep I have the same issue. When rear channel should fire only height does 

Same here (arc ultra and 2x 300s), they will get a lot of returns if they don’t fix this ASAP

 When I run a Dolby Atmos 7.1.4 channel ID test I get sound from the outboard side of the 300, then the inboard side of the 300, then the top of the 300.  Maybe TruePlay is flawed if it’s not reproducing those three locations.

 I will say that I don’t think the physical isolation of those channels in the 300 is that good.  Too much bleeding into other areas of the speaker.

Exactly, this is the issue we are having. 

Hi​​​​​ ​@lacerate 

I personally was not aware, no, but we (Sonos) already were, yes, and we are investigating.

I hope this helps.

Hi ​@Spaxx24 

Ah you caught me - my now removed post was written before I spotted that we were in fact already aware.

Thanks ​@Corry P 

Any idea on ETA for a fix?

Sounds similar to the problem we experience with the Era 100 as surrounds.

Hi ​@lacerate 

Sorry, but no - there never is.

I realize it’s impossible to have an exact date, but this is the sort of MAJOR bug impacting hundreds if not thousands of users and should be extremely high on the priority list.

I’m new to Sonos and I already had my fair share of problems (paid for express delivery, got the delivery one week late and with wrong products inside, took close to 3 weeks to get what I paid for….), but this should be fixed asap. It’s not a good look for new customers, possibly even worse for old one who already had to deal with the app fiascos that I read about and hoped were being fixed

I can understand the Sonos hesitation to post dates. Not saying I like it.

If they get bad press over a problem it eventually fades, if they miss a date they get a fresh round of roasting.

They do have their pending fixes site that is some help.

https://trello.com/b/4T9rbg8t/sonos-app-improvement-bug-tracker

Exactly this.

And as we talking about rounting of drivers.

On the Ultra the "wide channel" for the marketing 9.1.x should just play the L/R also. I would give a so much wider soundstage and the "wide channel" in Dolby Atmos is rarely used so this 9.1.x markting is kinda unnecessary.

don’t see anything about this era 300+ultra problem mentioned in that Trello board. See Lost of minor improvements tho. Seriously hope this is going to have precedence over “ui Fit and finish” lol

Isnt that Trello for the app. This isnt an app issue (most likely)

This is a problem on my Ultra/Sub/300s system as well. I await the outcome from Support. 

You’d think validating that the correct channels are being played through the correct speakers would be entry-level quality assurance for a surround-sound product. It’s pretty remarkable that Sonos continues to have very little rigor when it comes to quality assurance.

I have the same issues mentioned. I contacted Sonos support and submitted a diagnostic test to them when the sound on the Dolby 7.1.4 test should be playing out of the rear surround channel. The sound from the rear surround channel comes out of the hight tweeter as mentioned by OP instead of the inward facing tweeter/woofer pair on both Era 300 units. I even switched them over and reconnected them to my system and the same issue persists. It is worth noting here that the outward facing side of the Era 300s plays the test sound for the left and right surround speakers as normal in tandem with the Arc Ultra’s side facing tweeters. 
 

For clarity, I am referring to speaker configuration here Dolby Home Theatre Speaker Guide. The speaker position 6 is the issue. When testing this position for both speakers, the sound comes from the hight channel, number 8 on this set up document, instead of the inner driver pair on the Era 300. Sound from the rear surrounds seems to be routed to this driver for some reason. Number 5, left/right surround, works perfectly fine and has both the Era 300s and Arc Ultra’s side drivers activated to create this channel. 
 

​@Corry P would you be able to tell us when the Sonos team were first made aware of this issue? Understand that you can’t tell us when a fix for this will be implemented and I don’t expect it to be fixed soon, but would be interesting to know when Sonos was made aware of this issue as it drastically impacts the immersion and effectiveness of the surround sound. Can’t wait to get my system firing in all cylinders (drivers) again. Thanks for the support! 

Hi ​@Lewdog129 

I don’t have information on that either, but the Arc Ultra was released on 29th Oct 2024.

Well i really hope they didn’t release it knowing it was actually broken….

I would definitely expect this to be fixed soon. We’re talking about sonos’s flagship surround Product, a very expensive one, not correctly reproducing surround sounds. This is major and if Sonos is a serious company they should have this fixed in no time 

It is not the Ultra that is broken, people with regular Arc has this too.

I am with you here. Paying £449 per rear speaker and only to get less than 50% of it working due to the issue is not acceptable at all. Completely unacceptable given they are advertising it as an ultimate surround experience and you don’t get that in its current state, far from it. Made me think I had two defective Era 300 units at first. I said I don’t expect it to be fixed soon, more as a statement of the current state Sonos is in with the app and software quality assurance issues. In hardware terms, the products are solid and the capabilities are there, it’s just the software for both the app and hardware that drastically lets an otherwise stellar product down.

I would like to see updates on this issue from the Sonos team as they progress through working out a fix. However, I’m not holding my breath on this. 

I can confirm this issue affects the original Arc too. I just tested my Arc + Dual Subs + Era 300s setup using the 5.1.4 and 7.1.4 Dolby Atmos Test Tones videos on Blu-ray disc. The inside-firing drivers don’t play any audio during both tests. 

​@Corry P Another problem I noticed is both REAR height channels are playing through the Arc instead of the Era 300s. So the only driver currently being utilized on the Era 300 (when used as surrounds) is the outside-firing driver.

An interesting note about the rear surround issue is the rear surround channel now sounds louder playing through the outside-firing driver. For some reason Sonos has always had the inside-firing driver play at a much lower level compared to the outside and upward-firing drivers. Maybe this is intentional because so many users sit so close to the surround speakers.

EDIT: I unplugged the Arc from power for 15 seconds and re-ran the tests. The rear height channels are playing correctly now.

Thats interesting, for me the rear-height is definately firing.