Feature Request: Arc Ultra Center Channel Control

​@nathug75 How did you reach the conclusion the Arc Ultra center is 4-6dB too loud? Is this before or after Trueplay. Did you try tuning down voice enhancement?

I’ve been working with an app producer called Native on a AppleTV and iOS app called Sound Test - Sound Test for Dolby Atmos over this past year. I have been doing a lot of tests with this on various system I own, including my home Denon / Q Acoustics 5.1.4 system.

The last few weeks I have been demo’ing an Arc Ultra with ERA100 surrounds and a Gen 4 Sub for my new homes smaller TV room.

With this app and a program called Smaart by Rational Acoustics and a dB calibrated microphone, I can measure each speaker level of a system individually and also see its EQ curve. I did this after using the full Trueplay on my iPhone 17 Pro Max with no case.

Trueplay very much surprised me and did a fairly good job of leveling the system, and leaving everything flat and loudness off, it sounded great and the EQ graphs were fairly close too what I would expect from a Sonos, which is mostly flat and a 8-10dB boost in the low end. The sub was well matched with the Arc also.

I tested it with this system because I was noticing the voices were very pronounced over all my other systems, and when the camera moved the voices were getting quieter as they were moving from center to left or right. I also noticed that music was quieter too. Doing this test proved that the virtual center speaker that the Arc is creating is much louder than it really should be. 

I have not tested the previous Arc, yet I understand that it does not have this issue.

And don’t get me started on the lip sync! And before anyone says anything, I have all my setting correct, and the audio is behind the video so there is no saving it. It's out by around 65-75ms, which I believe is the internal processing of the Sonos infrastructure. This was tested with CatchinSync iPhone app and their test videos. All my other systems are within 8ms!!!! Same TV and 8k HDMI cables.

I can live with the lip-sync as its just under the 2 frame limit, but the center is driving me nuts and too the point I may return the system. 

Hope this explains it :)

Haven’t noticed any lip sync problems on mine. The center being loud was mentioned before, see 

Regarding your measurements - you sure put a lot of time and effort in what is a consumer grade set up. Sonos has stated the Arc Ultra is meant to deliver an experience, not to play test tones from all the right places. This could be an explanation for what you are measuring.

The “internal processing of the Sonos infrastructure” (otherwise known as a buffer) for the HDMI-ARC input on the Arc Ultra is defaulted to 30 ms.  If you are experiencing a longer delay (and haven’t increased it in the Settings > Arc Ultra > TV Dialog Sync menu), then the delay is coming from the source, not the Arc Ultra.

Some people don’t ever notice lip sync issues, but believe me it’s there. Go get CatchinSync and test it. Once you see something fully in sync, it’s hard to miss. In my line of work video and audio has to be within 2 frames, preferably 1 or less.

The Arc Ultra is advertised as an until that can do Dolby Atmos 9.1.4, so I would fully expect it to align with the Dolby Atmos spec or there abouts when set up correctly. So being able to send test tones to correct locations shouldn’t be a huge task for it, and it does it well. Yet! Having the center almost 2x louder than it should be, should not be the case. We should 100% be able to control it, even at a consumer level. In my opinion.

As I mentioned in my set up the audio is behind the video, so no amount of delay added to the audio with work, it will make it worst.

My old LG C6 you could delay the video, my new G5 you can not. Sadly.

For the record the 30ms is with a PCM audio and not Dolby Atmos with is closer to 64ms, which is what I’m seeing. This is confirmed on the rTings website and their own tests. Please check it out.