How about a console console table with two large baskets underneath to hold the wires. You could make a hole in the back of the basket to channel the wires through.

Thanks Beverly - these speakers are built into our ceiling. They're legacy and need wires.

If the speakers are built into the ceiling, why do wire show at all? Don't they run from the ceiling to the TV above the ceiling and through the walls?

another choice is a bench with lid or drawer. cut holes in the back for the wires to escape (and make sure you dont have heat building up) but then you can use it as a window seat, too.

An AV receiver is going to be at least 16" deep, plus you need to leave at least an inch for the depth of the HDMI cable. The Sonos Play bar is a good solution, but you still have to put the cable box somewhere. There are options depending on where you live, such as a client box for the genie system from Directv, which can go behind the TV. Otherwise, maybe have a custom cabinet built under the window that conceals the wires and power outlet. Build it so it extends to the perpendicular wall and you can keep the AV equipment horizontal instead of vertical.

Just get bluetooth speakers and digital tv like appletv. There is no need for an AV receiver or any components in 2016

@shiningautumn8 - this is not great advice. You have not met them or spoken to them about their wants and needs. Maybe they need or want broadcast TV/cable/Directv. The OP stated there are speakers in the ceiling, maybe they want to use these. Sometimes it is better to help solve the problem they are asking about.

Either a console or a long rectangle storage ottoman to be used as a window seat combined with creative shelving design for the wall between the window and the fireplace.

[https://www.houzz.com/discussions/creative-solutions-for-hiding-speaker-wire-dsvw-vd~3777881?n=7[(https://www.houzz.com/discussions/creative-solutions-for-hiding-speaker-wire-dsvw-vd~3777881?n=7)

My favorite set up is putting the cable box and ps4 next to the couch under the side table. The wire run in the wall. And then under/behind the floor molding. And then back up to the tv. Or if possible in the crawl space. We did it once ourselves and another time we hired someone. Worth every single penny. People are always wondering where the cable box is. It is pretty neat. And yes the controller works just fine. I just got super super long wires from Amazon.

You're wanting to get the wires piled on the floor beneath the window to connect to the tv on the mantel and vise versa to get sound from the tv to the ceiling speakers via wiring hidden behind the wall?

Like the basic idea behind these pics. Enclose the wire in a "pipe" and then make the pipe decorative.

https://www.architectureartdesigns.com/15-creative-ideas-how-to-hide-the-cables-in-your-home/

You could have the pipes create a grid from window sill to base board and from left wall to fireplace, then snuggle one into the corner left of the fire place surround above window sill height. Once you get to the mantel with the wires, there are different paths you could take.

You could add a wood "frame" on the wall around the tv to match your window framing and use that to help you hide the wires and/or add a container to the left side of the mantel and add the wires through the container -- perhaps a hollow ceramic jar or a wood jewelry box.