We have had an Arc SL for several months. Once it got warmer, and our central AC unit started kicking on, we noticed that the sound would cut out any time the AC came on. Facts from testing: source doesn’t matter; TV, appleTV, AirPlay from phones, even if that’s all off and Sonos Radio is playing. If the AC kicks on, the if the TV is on we see the volume drop to 0. Wait 10-15 seconds, and we can turn it back up. If airplay, the audio stops and it looks like it’s disconnected from the source. If Sonos radio, the song just stops and volume has dropped. We thought it might be a signal from the central AC (ie wireless signal/interference from the thermostat), but we had the whole unit and thermostat replaced 3 days ago (yay for AC breaking in the middle of the summer) and it’s still happening, even with the new old-school wired thermostat. I’ve connected the Sonos power to an external battery, and it happens with that, too (ie isn’t subject to power surge from the AC). thoughts?

Answered

bizarre sound cutout on Arc SL

9 months ago
23 July 2023
9 replies
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DSpar
Contributor I
3 replies

We have had an Arc SL for several months. Once it got warmer, and our central AC unit started kicking on, we noticed that the sound would cut out any time the AC came on. Facts from testing:

source doesn’t matter; TV, appleTV, AirPlay from phones, even if that’s all off and Sonos Radio is playing. If the AC kicks on, the if the TV is on we see the volume drop to 0. Wait 10-15 seconds, and we can turn it back up. If airplay, the audio stops and it looks like it’s disconnected from the source. If Sonos radio, the song just stops and volume has dropped.
We thought it might be a signal from the central AC (ie wireless signal/interference from the thermostat), but we had the whole unit and thermostat replaced 3 days ago (yay for AC breaking in the middle of the summer) and it’s still happening, even with the new old-school wired thermostat.
I’ve connected the Sonos power to an external battery, and it happens with that, too (ie isn’t subject to power surge from the AC).

thoughts?

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Best answer by Airgetlam 23 July 2023, 21:59

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9 replies

Airgetlam
38892 replies
9 months ago
23 July 2023
Answer

Sounds like your A/C motor is a source of wifi interference . I wouldn’t have expected the source to be the thermostat itself, but you’ve already removed that as a potential source.

It’s not clear from your post if your system is hanging off your Wi-Fi, or off of SonosNet. Either way, I’d be testing the use of another channel (1, 6 or 11) to see if there’s less impact, or if the A/C motor is broadcasting across all of the radio spectrum. I’d also recommend having an engineer take a look at that A/C motor to see why it’s generating that interference.

DSpar
Author
Contributor I
3 replies
9 months ago
23 July 2023

Makes sense, but still bizarre; it’s a completely new AC motor. That means we’d have 2 wholly different AC units/motors throwing the exact same interference.

DSpar
Author
Contributor I
3 replies
9 months ago
23 July 2023

And it’s on our WiFi; I’ll see what I can do re: that

Investigate the possibility that there is a duplicate IP address associated with the air conditioner controller.

Hadn’t thought about that as a possibility, but it’s a valid point, @buzz .

In any case, assigning reserved IP addresses to all your network devices in your router’s DHCP table (see the manual for your router, they all seem to be slightly different) is just good housekeeping for a network. I learned how to do that years ago, after some initial and ultimately nonsensical trepidation, and it has certainly helped my network immeasurably from the occasional mess up.

As we were typing I was investigating a very bizarre issue on my own network. Actually it turned out to be two issues. Testimony to my regular comment that once you’ve assumed that the problem must be [...] or cannot be [...] you are likely to be blindsided.

My ISP’s router has a checkered history if one digs around on the Internet. I have two WiFi networks and the one associated with the ISP’s access point started rejecting my Android and iPad. I also noticed that the SONOS system had jumped to the other WiFi access points. (My SONOS system is aware of both) I hadn’t rebooted my router in a while and rebooting solved the WiFi issue. One must keep this router on a short leash.

As I was updating the router’s IP address reservation table (for recently added and deleted devices), I noticed a duplicate. This should not have been possible, but one must keep in mind that this router is not the brightest kid on the block. I couldn’t deal with this by working only with the router and expanded my arena. Eventually I found that my SYNOLOGY NAS, in spite of my explicitly setting it for DHCP, was actually using an address that should have been used only during emergencies (previously I was not aware of this “feature”) rather than an address from the DHCP server -- resulting in a duplicate. Fortunately, the duplicate device was rarely used at the same time as the NAS and the duplicate was therefore unlikely to have caused much trouble. My solution was to change this address and reserve the new (now unique) emergency address in the router.

I’m now wondering if some of the odd issues reported by users that involve SYNOLOGY NAS drives might be caused by this. I can imagine that, if the router’s DHCP server is pokey for some reason, the SYNOLOY will resort to using the emergency address.

DSpar
Author
Contributor I
3 replies
9 months ago
24 July 2023

Fun aside; turned wifi off on the Sonos and wired it directly to the router; still happened 2 seconds ago (sound cutout with AC coming on).

also, new AC unit is non-wireless, should have said that earlier. But broadcast interference still makes the most sense.

I am far away from being a network specialist (see prodigious use of apple products above 😉) but I’ll have some more knowledgeable friends take a look.

thanks for the input!

The interference I was suggesting was electronic noise from the A/C, and not from a Wi-Fi device. Not unlike the interference I got from a failing microwave back in the day. But it happening while wired certainly lends credence to @buzz’s contention of a duplicate IP address issue, it’s much harder (although not impossible) for broad spectrum interference to penetrate CAT-X wiring.