I'm using this mount for the soundbar: Amazon.com: Mounting Dream Soundbar Mount Sound Bar TV Bracket with Holes/Without Holes, Non-Slip Base Holder Extends 3.4" to 6.1", Up to 20 LBS, Safe and Easy to Install MD5425 : Electronics It hold the Q990F with no problems. With a larger TV you may need longer brackets which Mounting Dream will ship to you for free. All you have to do is ask.
Put it on a Mantel Mount and use a 3rd party soundbar mount like this: Amazon.com: Mounting Dream Soundbar Mount Sound Bar TV Bracket with Holes/Without Holes, Non-Slip Base Holder Extends 3.4" to 6.1", Up to 20 LBS, Safe and Easy to Install MD5425 : Electronics You can get longer brackets on request for a large TV. I'm using that combination with a Q990F and while I'd love not having a TV over the fireplace, it's the only place to put it.
I have my TV on a Mantel Mount and I'm using this for the soundbar: Amazon.com: Mounting Dream Soundbar Mount Sound Bar TV Bracket with Holes/Without Holes, Non-Slip Base Holder Extends 3.4" to 6.1", Up to 20 LBS, Safe and Easy to Install MD5425 : Electronics Works great. Mounting Dream does have longer brackets for larger TVs and they'll ship them to you free of charge. All you have to do is ask.
Remount the TV with a Mantel Mount and one of these: Amazon.com: Mounting Dream Soundbar Mount Sound Bar TV Bracket with Holes/Without Holes, Non-Slip Base Holder Extends 3.4" to 6.1", Up to 20 LBS, Safe and Easy to Install MD5425 : Electronics
I'm using this one. Works great since my TV is on a Mantle Mount so it moves with the TV: Amazon.com: Mounting Dream Soundbar Mount Sound Bar TV Bracket with Holes/Without Holes, Non-Slip Base Holder Extends 3.4" to 6.1", Up to 20 LBS, Safe and Easy to Install MD5425 : Electronics
Been using this one with the 990F since October. Mounting Dream will send longer brackets for larger TVs free of charge: Amazon.com: Mounting Dream Soundbar Mount Sound Bar TV Bracket with Holes/Without Holes, Non-Slip Base Holder Extends 3.4" to 6.1", Up to 20 LBS, Safe and Easy to Install MD5425 : Electronics
First, ignore the too high idiots. They have nothing better to do. That out of the way, I am a big Mantel Mount fan so consider it. But even if you don't, you can get a soundbar mount like this one that I'm using with Q990F: Amazon.com: Mounting Dream Soundbar Mount Sound Bar TV Bracket with Holes/Without Holes, Non-Slip Base Holder Extends 3.4" to 6.1", Up to 20 LBS, Safe and Easy to Install MD5425 : Electronics Pic to give you an idea.
Here's my solution. Soundbar: Amazon.com: Mounting Dream Soundbar Mount Sound Bar TV Bracket with Holes/Without Holes, Non-Slip Base Holder Extends 3.4" to 6.1", Up to 20 LBS, Safe and Easy to Install MD5425 : Electronics Rear speakers: USX MOUNT Adjustable Height Speaker Stand for Satellite & Bookshelf - 11LBS Capacity - Walmart.com
I'm using this one. If you have a large TV Mounting Dream will send you longer brackets. Here's a pic. I'm using a piece of cardboard to hide the brackets. And yes, the TV is on a Mantel Mount. Amazon.com: Mounting Dream Soundbar Mount Sound Bar TV Bracket with Holes/Without Holes, Non-Slip Base Holder Extends 3.4" to 6.1", Up to 20 LBS, Safe and Easy to Install MD5425 : Electronics
I used this to mount a Q990F: Amazon.com: Mounting Dream Soundbar Mount Sound Bar TV Bracket with Holes/Without Holes, Non-Slip Base Holder Extends 3.4" to 6.1", Up to 20 LBS, Safe and Easy to Install MD5425 : Electronics Works great but I needed to request longer brackets which were shipped to me, free of charge.
My $0.02 based on experience similar to yours so take it for whatever it might be worth to you. Use a Mantel Mount above the fireplace combined with this for the soundbar: Amazon.com: Mounting Dream Soundbar Mount Sound Bar TV Bracket with Holes/Without Holes, Non-Slip Base Holder Extends 3.4" to 6.1", Up to 20 LBS, Safe and Easy to Install MD5425 : Electronics Honestly, it's the best solution rather than trying to mess around, squeezing square pegs into round holes. Here's mine. Not a work of art by any means (and my usual note to lurkers. The TV is at a perfect height pulled down and with the blinds closed, no reflections. 77" LG OLED with the Q990F (which is currently on sale on Woot--US model--for $897.
I used this to mount the soundbar directly to the TV: Amazon.com: Mounting Dream Soundbar Mount Sound Bar TV Bracket with Holes/Without Holes, Non-Slip Base Holder Extends 3.4" to 6.1", Up to 20 LBS, Safe and Easy to Install MD5425 : Electronics

