Mounting the Sonos Arc with MantleMount MM340 and SBXL Sound Bar Adapter XL

Sonos arc mantelmount 3

We’ve been using MantelMount’s MM340 pull-down TV wall mount ($299) with our 55” LG C9 for the past few years, but we haven’t gotten around to mounting the Sonos Arc yet, because life just gets in the way sometimes.

That meant experiencing full Dolby Atmos with the Sonos Arc required the TV at its retracted position above the mantle, which is too high for longer viewing durations. When lowering the MantleMount MM340 to its lowest position, that meant the Arc was behind the TV.

So after some research, mounting the Sonos Arc sound bar to the MantleMount MM340 requires the latter’s SBXL Sound Bar Adapter XL, which we bought online from for $49.99 CAD. These are essentially two universal “L” shaped brackets made to fit behind your TV to mount a sound bar such as the Arc. The MM340 does not come with sound bar attachments like the MM540.

To install the brackets, we had to remove the pull-down handles for the MM340 temporarily. You can see how the bottom wall mount screw holes attach the bracket to the TV, while the lower brackets attach to the rear mounts on the Sonos Arc (ignore the messy cables and bias lighting strip that fell down):

Sonos arc mantelmount 5

The Arc mount holes are about 24 inches apart and you’ll need M5 screws about 16-20mm depth available from your local hardware store, plus some washers. You will need someone to help hold the hefty Arc (13.7 pounds) while you attach and centre the soundbar to the rear mounts.

We kept some decent distance from the bottom of the TV and the up firing speakers for the Arc aren’t impeded in any way.

Sonos arc mantelmount 4

Here’s how it looks from the bottom—there are some visible parts of the brackets showing but it’s not that obvious or visible from our sitting position (the mount could use some tweaking to perfectly line up):

Sonos arc mantelmount 2

Here’s a view from the side of the front-mounted Sonos Arc:

Sonos arc mantelmount 1

We eventually will have to adjust the MM340’s installation height since there’s not enough clearance for the TV and Arc to clear the mantle (note to self, mount TV and sound bar at the same time next time). But for now, this viewing position works fine and the TV and Arc have plenty of clearance from the fireplace. Also, we’d highly recommend MantleMount’s Wall Plate Covers to hide most of the mount behind your TV (wife approved).

To hide the jumble of cables behind the TV, we used black gaffer tape, this large cable cord organizer box for the power bar, and this cable concealer for the Sonos One power cables along the top of the mantle (again, wife approved).

Differences with the Sonos Arc mounted up front now, coupled with the company’s Sub Mini? It’s sublime listening to music and watching movies and shows in Dolby Atmos on an LG OLED TV with the Apple TV 4K.

You can click here to learn more and buy the Sonos Arc on the Sonos website.