New Sonos Arc oil/grease on side grille




Recently purchased a brand new sealed Sonos Arc and upon opening, I’ve noticed some oil/grease marks on the side grills. I spoke to the retailer who is well known in the UK and a swap was arranged. Just opened the new unit today and the same issue. The retailer has been sent the pictures and they are going to swap it again for me tomorrow.

Anyone here experienced similar issues? It’s annoying as I’ve never had issues with Sonos and the packaging was intact on both deliveries including all seals etc.






Best answer by Sotiris C. 16 November 2022, 12:28

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Userlevel 5
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From the Sonos User Group forum on fb..


Userlevel 5
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Reading several replies on the fb post I posted the pic of, several comments said they had the same on their Arc and a micro fiber cloth took it off. 


I just noticed mine has these marks too on both sides.  I’ve had mine for just over a month.  

Userlevel 6
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Hello @edcor78 and everyone!

I would recommend contacting our Sonos Support if you haven’t, they will be able to assist you further.

I hope that helped.

Sotiris C

Userlevel 4
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After reading this post I checked my arc which about 3 months old and there are these same stains in both sides. Does not appear to affect performance in anyway so I will just leave it. 


I think I might have an idea what these marks are from.  It must be the Ferrofluid, the only liquid that can be found in speakers, which is commonly used to cool tweeters and make them perform better.  

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Link to related post in FB Group

Keep an eye on this. There might be a deposit on the inside of the grill that diffuses out through the holes. Probably it’s a good idea to register this with Support before attempting to wipe it off. If a single wipe deals with the deposit and it never returns, just ignore it. If the deposit returns, the end cap should be removed and the back side cleaned. This will void the warranty.

Userlevel 5
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Just purchased 3 new Arcs.. all 3 have these stains . 1 much more than the other 2. Microfiber cloth did not remove stains for me. Crappy quality control for sure.

Hey folks.

Only had my Arc + Sub. Gen. 3 set up a few days before these oily patches showed.

I used a fine microfibre cloth to gently wipe away the fluid when I first noticed it. Thinking it may have been condensation, resulting from the icy temperatures we’ve been experiencing. But the oily patches returned not long after.

To be clear. The SONOS Arc + Sub. Gen. 3 have been treated very carefully & both have been in an ambient temperature of between 19°C to 21°C.

But in my case this bleeding/leaking has evidently had a slightly detrimental effect on the sound. Dialogue especially doesn’t seem quite as clear or focussed. Generally sounding slightly less dynamic. As a consequence I’ve been compelled to increase the volume by 20-25% compared to a day or so after initial set-up. Even though the speech enhancement & TruePlay functions have been activated via the app(?)

Contacted SONOS customer service & chatted with a very helpful & understanding operative(Daniel) who offered me a replacement. But I’m just left wondering how these oily patches could negatively affect the performance of the Arc so drastically? And, after learning of other users’ experiences & reviews highlighting similar problems, the chances of this occurring with the replacement soundbar too(?)

Shame really. Until these issues arose I was very much enjoying the combo’s. fast, lean & punchy sound, relative simplicity of set-up & how intuitive the S2 app. was in use.



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@Bob-a-job …I’ve read that some have received reconditioned speakers instead of brand new when getting brand new unfortunately. I’m surprised Sonos has not posted or made  an announcement on what these stains are as the issue is growing with so many. Maybe @Sotiris C. can find out what this is. 

@Bob-a-job …I’ve read that some have received reconditioned speakers instead of brand new when getting brand new unfortunately. I’m surprised Sonos has not posted or made  an announcement on what these stains are as the issue is growing with so many. Maybe @Sotiris C. can find out what this is. 

Thanks for the info. Dogdad.

Bit of a bummer to learn that similarly afflicted SONOS Arc users are being sent reconditioned units.

Might be interested to know that until these grease/oil issues appeared on the Arc had been evaluating SONOS’ Arc + Sub. Gen. 3 against the SONY HT-A7000 & SA-SW5 sub.(with SA-RS5’s surrounds on their way).

For the regrettably short time before their sound was adversely affected, I did have a slight preference for how the slightly faster, leaner & tighter Arc + Sub. Gen. 3 combo. sounded in the admittedly awkward acoustics of our large L-shaped space. More especially so after True Play calibration was completed & speech enhancement activated in the S2 app.

Thankfully we’ve experienced no such issues since setting up the SONY soundbar & sub. directly connected to our router(via USB-Ethernet adapter), SONY Bravia TV, SKY Q box & Blu-Ray/Universal player. Which have worked pretty much flawlessly & seamlessly since installation.

SONY’s HT-A7000 soundbar & SA-SW5 sub. can seem a bit brutal & industrial looking to the eye at first. Especially in comparison to the slightly smaller & sleeker looking SONOS Arc + Sub. Gen. 3.

Thanks again.