is it expected for an Arc Ultra + Era 300 setup to always emit from thr arc ultra with lpcm 5.1 sources?

To follow up and answer some of my own questions here, I ran a test just now in which I configured the PS5 and Switch 2 to output in LPCM 5.1 but disabled surround speakers in the Sonos App by toggling the top option in the Surround Audio balancing screen.

Switch 2: When running the audio testing program now, I hear the front left / center / front right speakers all correctly as expected, but the rear left and rear right speakers I can now clearly hear coming from the Arc Ultra and without any other speakers causing confusion I can also clearly hear it is at least 50% louder than the actual front audio tests, which is insane since they shouldn’t be making either no sound or minimal sound purely in support of the actual rear speakers.

PS5 FF7 Rebirth: When a sound emitter is in front of me it is correct as I position it around the front/left/right positions, but when it moves to behind me the sound now gets LOUDER out of the Arc Ultra, significantly louder, which makes absolutely no sense at all. If I enable the rear Era 300s at any time the sound is even louder as it is now combined with the actual rear sounds being produced, which means any time you walk away from a sound in this game it’s about 200% volume compared to being right in front of you.

Adjusting the ‘TV Volume’ slider on the surround Audio balancing screen only seems to impact the actual rear speakers, no matter what I do any positional sound that starts moving towards the rear speakers is firing at very loud volumes through the Arc Ultra itself at louder than front facing sound volume levels, and this is despite having discrete speakers it should be piped to in the first place.

So LPCM 5.1 is just unusable on Sonos highest end sound bar and rear speakers, seems to be the only conclusion.

Have you checked the supported formats for Sonos speakers? https://support.sonos.com/en-gb/article/supported-home-theater-audio-formats
 

Yeah I’m aware of the supported formats, LPCM 5.1 is just “Multichannel PCM” which is sent over eArc as listed there, there’s no incompatibility and these are standard formats used for gaming devices, it’s infact the only way to do surround sound through a Switch 2.

Further testing just now I realized disabling the rear speakers in the settings does cause more ‘rear’ sound to be routed to the Arc Ultra itself, tho the surround sound slider doesn’t impact this audio the way it does the volume of the actual rears when they are enabled.

From what I can tell, in all scenarios and no matter what you do, even with Atmos (which does mitigtate the issue slightly due to better positional selection) there is just a huge amount of high volume side/rear audio that gets pumped through the Arc Ultra and destroys your volume balance and surround sound stage. With no sliders/eq/balancing options impacting this aspect at all.

An easy test to do is to stand in front of a sound source in ff7 rebirth and listen to it through the center channel, then rotate 180 degrees and listen with the ‘surround’ slider set to -15 so there isn’t much sound coming from the rear speakers, it’ll be way louder coming out of the arc ultra than it was even when you were standing right in front of the thing because its attempts to ‘help’ with the surround sound stage are completely imbalanced.

Reading this forum I can see that about a year ago the surround volume slider actually did adjust the volume of the side firing speakers, along with the surrounds, but people didn’t like that so Sonos unlinked them and then filed comments about side firing speaker control as a feature request and never responded again.

I suppose this explains why it’s impossible to even attempt to balance them.

I’ve been playing around with this all day and it’s almost unbelievable how much worse the surround experience is with this arc ultra and rear 300s than my old arc + ones setup, or any regular av setup I’ve used.

no matter what settings I screw with on the consoles, tv, or Sonos app, the sound balance in surround gaming is just completely broken. It’s hilarious to be standing right in front of a person talking in ff7 and hear them at regular center volume but then turn around to walk away and all of a sudden they are blasting out of both the soundbar and the rears creating a cacophony of sounds, with my only option being to essentially mute the actual rears and even doing so the ultra is still pumping louder sounds when a sound source is considered behind me than in front of me.

There desperately needs to be an option to just say no to the soundbar rendering rear channel directed sounds when you have actually surround speakers, or maybe someone at Sonos needs to play more computer games when forcing this kind of configuration which seems exclusively designed for atmos film viewing.

Just something you might try. However I don’t know how much or what adjustments you’ve made to your PS5 but I suggests a factory reset to out of the box state. Then make sure Speech Enhancement is turned off on the Arc Ultra. Let us know the results.

Edit:

A search for audio issues with FF7 are all over the internet.   Below is a Reddit post 

https://www.reddit.com/r/FinalFantasy/comments/1b3hqlo/ff7_rebirth_audio_quality_issues/

You mean a full factory reset on the console? That’s a pretty unnecessary step since I can easily configure the handful of sound options it has, and fully replicate the issue on my Switch 2 through different means, it’s just easier to test on the PS5 as standing next to a radio in FF7 Rebirth creates a constant sound source where I can manipulate its position quickly. Speech enhancement in the Sonos App as well as everything else that could impact things is off.

I found this thread describing basically the same issue: 

They don’t have surrounds and are mistaking ias a left/right/center balancing issue, but in my testing I can replicate the same behaviour with or withour my surrounds being added in the sonos app.

Basically, whenever a sound source moves from in front of you and passes the left/right side and starts to be partially or fully behind you, the Arc Ultra is working hard firing extremely high volume sounds trying to virtualize and support the rear intended sounds. Significantly louder than when the sound is just in front of you and firing from purely center/left/right channels. This can be even worse when you have discreet rears like I do and configure them at appropriate volumes as it now comes out of both vectors, but is clearly noticable even without actual rears when the Arc Ultra is rendering 5.1 with a sound source asking to be played towards the rear.

I don’t know if this is related to all of the Arc Ultra updates they’ve been pushing across the last year to address everyones film/atmos balancing complaints but it’s pretty frustrating compard to what I’m used to, I do know that removing the ability to adjust the surround firing volume from the Ultra itself as they did in March 2025 when decoupling discreet rear volume from arc ultra rear rendering volume means I can’t actually do anything about it at all.

The QA test case is quite simple if someone at Sonos wants to test it, configure eARC + LPCM 5.1, stand on front of a radio or person talking in Final Fantasy 7: Rebirth, spin the camera 135-180 degrees so they are behind you, observe the volume coming from the Arc Ultra is now 150-200% of what it was when the sound source was in front of you depending on your exact rotation. With or without dedicated surrounds.

Or on Switch 2, set the output to LPCM 5.1 over eARC and simply run the audio tester and note that when it tests the rear left/right speakers you get as much or more volume out of the arc ultra than when it’s testing the front left/right speakers, again with or without dedicated surrounds.

​@SMishra 

Read the “Edit” to my post.

Yeah I can tell about the distance fade configuration and where the listener is positioned in 3d space, my day job is making games so it’s not too unusual for me to analyze this stuff.

the issue is present on both machines in all testing, ff7 is just an easy test case and the game I’m currently playing. But as I said you can clearly hear it even in the Nintendo audio testing screen.