Everything else Sonos makes is great.  That’s why it’s so disappointing.   Most of the other products all have a similar sound signature:  warm, punchy, dynamic... belies it’s size.   The Arc is just completely out of step with everything else sound wise. It’s like a completely different company made it.

At this point I really wish it was just a bigger more dynamic 5.1 Playbar replacement.  I think most people would have loved that.  The Atmos feature of the ARC for me is way overhyped.  Most of the time it’s almost unnoticeable.   If you have the perfect size room with 8 foot ceilings, flat side walls, etc it’s impressive.   But with most average living rooms the pseudo effects will struggle.

I was suffering from the same issue.  After I read this thread I contacted Sonos support and was escalated to senior support who actually set up a night time appointment and called me to troubleshoot.  I am playing through an LG OLED 77C9.  Spectacular TV BTW.  We ended up with two solutions that fixed my issue.  I switched HDMI from pass through to auto in the LG HDMI settings and replaced the Sonos ARC supplied HDMI cable with a “higher” end cable.  That fixed the issue and ATMOS now sounds amazing through the ARC.  Night and day difference from before to after.  Good luck with this possible solution for LG users.

That is super interesting.  Did they send you the new HDMI? That is one of the most debated things in audio, whether a digital cable (HDMI/Optical) can affect sound quality.  Most argue it makes no difference, as you either are receiving the 1s and 0s or you’re not.  Which one did you get?

You can pay 100s-1000s of dollars for a premium HDMI from companies like AudioQuest.

A good cable makes a huge difference. I have a Audioquest Cinnamon hooked up to my beam.The sound quality is certainly noticeable.

Whether it will solve Arc problem-give it a try!!!

What was the exact problem? I have a LG 55NANO866 and I’m using the original HDMI cable but I don’t have a problem with Atmos. This always works.

If I use a ‘platinum’ premium HDMI cable, I guess the Arc would produce a more ‘platinum’ metallic sound, vs a ‘copper’ metallic sound?

:-) 

So the Sonos supplied cable is cheap rubbish and we need to all go out and buy a high end cable to magically fix this issue?

To clarify I don't notice this issue and am using the Sonos supplied cable.

Anyone know what the Sonos cable is, is it a capable of 48gbps (hdmi 2.1) or up to 18gbps?

I read this forum since the arc premiere because I have the same problem. With no warmth in the sound, unbearable highs not to mention the sssss. After the update the problem is still there. This update has not fixed anything in my case. I'm going to exchange my arc for another one, I'm still on time. But if this is not fixed I return everything. By the way I have arc, sub and two sonos 1 rear and it still sounds just as bad. I come from the playbar, with sub and 2 one, no point of comparison.

Very well put and exactly how I feel.  

I read this forum since the arc premiere because I have the same problem. With no warmth in the sound, unbearable highs not to mention the sssss. After the update the problem is still there. This update has not fixed anything in my case. I'm going to exchange my arc for another one, I'm still on time. But if this is not fixed I return everything. By the way I have arc, sub and two sonos 1 rear and it still sounds just as bad. I come from the playbar, with sub and 2 one, no point of comparison.

And if this is the reaction from seasoned Sonos owners who are not afraid to admit the problems the Arc co-creates then the bar itself must be technically inept.

It's brave of those already deep in the Sonos system to voice serious concern (especially within the company's own forums) on how unhappy they are with the Arc. These people really have been the bread and butter for Sonos but it now seems they are unrewarded for being loyal. I see lots of posts saying Sonos will fix this, but will they, I understand the following some may want to show given the revenue they have pumped into the system and I do hope their faith is correct. I just don't understand why Sonos released this in the first place as an inferior product to its already better line. 

I’ve been following this and other “ARC not working” threads for quite some time.  Recently my ARC finally arrived and it sounds great!  I have it integrated with a SUB Gen 2 and 1 SLs for surround.  It has replaced my old Playbar/SUB/Surrounds. 

I did the trueplay tuning with an old gen 1 iPad Pro.  I made a series of measurements first with the Playbar and then with the ARC.  I did this on the 25th July - which I believe is before the 12.0.3 update.

I am not hearing any of the problems that people are reporting and it definitely is better for dialog than the playbar.  I have not listened at super-high volumes (certainly less than 50%).  Music also sounds good.

Here are the measurements I made with REW. 

First a comparison of the two full systems with sub in place and trueplay on.  As you can see from the two curves, the ARC if anything has a flatter frequency response than the playbar.  The playbar peaks badly above 10kHz.  Note that I tuned the Playbar with the same iPad Pro but at least two weeks earlier (so it is just possible that Sonos has changed the way trueplay analysis methods in the meantime).  And I definitely have NOT got the two curves mixed up!!

Next is a comparison of the ARC out of the box with the playbar.  no SUB or trueplay.  Here you can definitely see that it was trueplay that has caused the playbar to have a stronger response above 10kHz.

Finally ARC vs Playbar no SUB but with trueplay ON.

My listening tests bear out these measurements.  I’m not hearing any of the harsh  sounds or poor midrange I was fearing.  I am very happy. 

Has anyone who is reporting issues tried a different HDMI cable? 
Just curious if a high end cable may be a solution for some. 
 

High end digital cables are snake oil.

beyond an acceptable build quality, there is no difference….. as long as the 1’s and 0’s get from each end is all that matters.

Build quality matters in that, there could be a bad solder joint or the connector is slightly out of spec or built out of cheaper plastic…. but in terms of bass, treble etc there will be no difference.

the only other thing could be bandwidth, but as long as the cable is built to spec, there will be no difference.

yes, you could have a bad cable…. but that will be that it either works or doesn’t…. Maybe cuts in and out… but would not affect any EQ or sound quality 

‘Premium’ cables also tend to be fatter, less flexible and come with bigger HDMI connectors, and you may find they don’t physically fit, especially when space is tight behind a wall mounted TV/Soundbar.

I’ve been following this and other “ARC not working” threads for quite some time.  Recently my ARC finally arrived and it sounds great!  I have it integrated with a SUB Gen 2 and 1 SLs for surround.  It has replaced my old Playbar/SUB/Surrounds. 

I did the trueplay tuning with an old gen 1 iPad Pro.  I made a series of measurements first with the Playbar and then with the ARC.  I did this on the 25th July - which I believe is before the 12.0.3 update.

I am not hearing any of the problems that people are reporting and it definitely is better for dialog than the playbar.  I have not listened at super-high volumes (certainly less than 50%).  Music also sounds good.

Here are the measurements I made with REW. 

First a comparison of the two full systems with sub in place and trueplay on.  As you can see from the two curves, the ARC if anything has a flatter frequency response than the playbar.  The playbar peaks badly above 10kHz.  Note that I tuned the Playbar with the same iPad Pro but at least two weeks earlier (so it is just possible that Sonos has changed the way trueplay analysis methods in the meantime).  And I definitely have NOT got the two curves mixed up!!

 

 

Next is a comparison of the ARC out of the box with the playbar.  no SUB or trueplay.  Here you can definitely see that it was trueplay that has caused the playbar to have a stronger response above 10kHz.

 

 

Finally ARC vs Playbar no SUB but with trueplay ON.

 

My listening tests bear out these measurements.  I’m not hearing any of the harsh  sounds or poor midrange I was fearing.  I am very happy. 

Quit confusing the issue with facts!

Really glad to have found this thread. I just bought an Arc and was surprised by the poor audio quality. My older setup a pair of honest stereo speakers (AudioEngine A5s). At first setup, the was arc seemed sub-par in almost all respects, especially vocals. 
 

I followed one of the suggestions above - set arc pass through to auto in my LG B8 TV settings, and changed the hdmi cable. Happy to report that the sound quality has improved massively.

Unless your HDMI cable is defective change cable on digital connections should have no sound impact on on a $800 soundbar.  We are not talking about $10.000 system

I agree. This is the first time I’ve even considered switching hdmi cables for troubleshooting something. Based on the response from Sonos support (to user “Marco Sonos” above), the included cable being defective is a clear possibility.
 

More likely, the hdmi passthrough setting in LG TVs somehow causes audio issues in arc. Setting it to Auto helped fix it in my case.
 

Anyways, I’m glad that it worked out. Hoping this helps anybody else with an LG Tv running into the same issue.

Overall though, I’m not impressed so far. As a first time Sonos buyer, I was excited for this. The Arc still seems like a mediocre sounding and over-priced system with Atmos being its main saving grace. Might end up returning it after a few days and invest in build/upgrading a traditional wired home theater setup. 

Which premium HDMI cable are you using?

Can you try testing with the supplied cable and only change the setting to auto? And see if it sounds better only if change the setting and not the cable?

It’s not the HDMI cable causing the issue people.

I would have a hard time believing that changing the hdmi would do anything as well.  The ARC is even worse with music, and I’m sending that over WiFi via Tidal and Spotify.  The HDMI plays no factor in music transfer for me.

Can confirm. Sound issues come back if I change the arc pass through setting back to PCM. So the HDMI cable is definitely NOT the problem. Not sure why Sonos support prescribed it to a previous poster (maybe an extra precaution).

PCM just means stereo.  There’s absolutely no reason it shouldn’t sound good in stereo as well.  What a POS.

Some users are happy with their Arc setups. That’s great and I am happy for them. Other users, me included, find their Arc setups lacking. I have a full 5.1 setup with Arc, Suc, and two Sonos ones, and I experience the harsh S issue and the hollow sound. This ruins the listening experience for me.

Users also report that moving Arc helps, or that Trueplay with older iOS devices helps. Additionally, there are specific Trueplay “dances” that users recommend.   

From the above facts, here is what I think is happening:

1. Sonos Arc was tuned at the factory to a certain room size and shape. Testing was probably done for a limited number of scenarios, and for them it works well.
2. Trueplay also assumes certain factors about a room, such as (maybe) symmetry, wall material, etc. 
3. Thus, there are problems if people have different room setups that cause distorted sound signatures. For example, in my TV room: the Arc is on a cerdenza near a reinforced concrete wall. Across from it ( about 4.5 meters) is another concrete wall. To its left (looking at it from the sofa) is a big glass doorway, and to its right is an empty space (for the dining area and kitchen). Ceilings and floor are both reinforced concrete, and there are no rugs or anything of the sort. This is very different to what you may find in North America, and perhaps differs significantly from the settings Arc was optimized for. 

Now, the above *is* a problem, and Sonos should fix it. Could it be that due to Covid19 less testing was performed? Sonos, please address thus issues! Also @Scott - Sonos @Jean C. @Krishma M and others at Sonos: please don’t let us hang dry, and give us some intermittent updates. Keep us in the loop! 

As for some users on this thread: I am ecstatic that you are not experiencing problems. That’s great for you. This does not mean that “everything is fine” and that other users must be imagining things. Believe me, I am not imagining that the sound is problematic and worse. As someone who loves their Sonos setup, I want to just be happy with it. Instead, I am constantly A/B testing with other speakers. The effect of these problems is to make me, a frequent Sonos buyer, doubt my system and start considering other alternatives. Today, Sonos Arc is frustrating; once the sound problem is fixed, my Sonos system will once again bring me great joy. 
 

I think a lot of the people who are happy with the Arc are coming from listening to tv speakers.  Which in most cases, a Bluetooth speaker would be an upgrade.  You don’t see many people on here coming from another soundbar, and definitely not a decent hifi setup, praising the arc.  Poor or limited reference points.