Not much information to go on, unfortunately. 
 

I would recommend that you submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it. But don’t post the resulting diagnostic number here, they get sensitive about GDPR.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

Thanks Bruce

I have been having this popping sounds and does not happen all the time. I have been in contact with Robert C @ Sonos regarding this issue and I am waiting for a email response. This happens while watching tv and only while doing so. Does not matter what channel, or recorded series nor Netflix or Prime this happens out of the ordinary and scares the heck out of you as this sound is quite loud. I am only posting this as I was reading similar issues from Sonos customers. There is nothing so far on my part which was requested that has helped. I have sent pictures and information on my TV with serial number and how Sonos is connected. What kind of speakers i have with various pictures. I am still waiting patiently now for a reply. 

My Sonos Setup: LG 55” C1 OLED TV, Bit Stream input, Passthrough output, eARC, Sonos supplied HDMI cable. No speech enhancement enabled. Sonos Arc Ultra, 2 ERA 300 surround speakers, Sub Gen 3 and Sub 4.  

After trying many different options, I have found a permanent fix that has been working perfectly for me over the last five days and about 20 hours of TV usage.  Hopefully this easy fix works for others as well.  Here is my fix:

(1) Disconnect Sonos HDMI cable at Arc Ultra end and then firmly reconnect to Arc Ultra. 

(2) Disconnect Sonos HDMI cable at TV end (eARC HDMI Input) and then firmly reconnect to TV.

(3) Remove Arc Ultra power cable for 30 seconds and then reconnect and let Arc Ultra completely reboot.  You may also want to disconnect power cable from your TV, but I did not need to do that.  Use your TV and Arc Ultra and enjoy!

Good luck to everyone and I hope this easy fix works for others.  I’ll repost here if my clicking/popping sound reoccurs, but hopefully my problem is now fixed! 

I have tries these options and even replaced my HDMI cable and still the odd time it will make this noise. It does sound like a bolt of lightning struck it. Not knowing when this is going to happen is frustrating. I am listening constantly for this to happen yet it hasn’t happen for at least a month. Strange as I have not done anything to my system and after replacing my HDMI cable it happened again, so it was not the cable change. I do wish I could figure this out without worrying each time I watch something on my TV.

Hello, David again, I've noticed that my problem only happens when I ask the Alexa app questions. The reply will crackle and pop sometime. I probably jinxed myself with saying only happens. Thanks for all the help.