Maybe just see if selecting a different ‘fixed’ non-overlapping 2.4Ghz WiFi channel on your router will solve the issue. Select channel 1, 6 or 11 and if the router allows, set a channel-width of 20Mhz only -

Set any other non-Sonos devices near to the Beam, to use the 5Ghz WiFi band, where practicable, to reduce any WiFi interference and move away anything using Bluetooth, or Zigbee (smart-lights etc.).. at least one metre away.

It’s often a good thing to reboot your Sonos devices, after making the changes suggested above.

Hope that resolves your issue.

Thanks, Will look at changing the wifi channel to see if that helps.

System has work fine since configured/fitted since 2019 with no issues, no changes to the other equipment nearby that use wifi.

When the TV is the source to the beam there is no drop outs to the sub and/or surround, tends to indicate that the wifi link between these units is stable.

Its only when a switch the source to internet radio (BBC Sounds) or from NAS drive do i experience these drop outs.

This has only started happening within the last week.

Routers can sometimes change their channels automatically on startup/update and the same may apply to neighbouring properties too. So a router channel change and power cycling the devices is worth trying initially, to see if that resolves the issue.

Router 2.4ghz fixed to channel 11

Sonos set for channel 11

Recycled power on router and all sonos units.

Turned off all nearby other WiFi equipment.

Same issue, constant drop outs when source is internet radio or nas drive. Only way this works is to turn off sub and surrounds in the app and drop outs stop.

No drop outs at all with sub and surrounds enabled when TV is the source.

Going to run a lan cable direct to the beam from router as next step  to see what difference that makes.

@richardbsimpson, 
That’s quite ‘possibly’ why you’re experiencing the issues mentioned… The SonosNet channel needs to be at least 5 channels away from your chosen router 2.4Ghz channel - try the router on Channel 1 or 6. If the router allows, also set the 2.4Ghz band channel-width to 20Mhz only.

The Sonos wired device for the SonosNet signal, needs to also be set at least one metre (or more) away from the router or other wireless device.

Reboot after making the suggested changes.

Hope that assists you to resolve the issue.