Speakers near fireplace

The fireplace will absolutely affect SQ.

You might want to experiment with panels of different
material that are cut to match the fp opening.

It should be possible to have your cake and eat
it too: a nice looking setup when the fireplace is
cool, good sound when also playing music
(with or without a back panel), and the ability to move
the speakers and the panel away, when things get hot.

bearskin rug and SQ be darned!!!!!!

just kidding..

two out of three pairs of Vandersteens we own flank fireplaces. The 7 and before that 5a were for years powered by an Ayre amp off to the side. On unequal wire length for a time and phase accurate speaker designed for biwiring, I and I believe the designer would advise equal lengths, you can always always listen and let your ears guide you. I managed to get the Ayre stereo amp close enough to use two 9’ wires..Have monoblocks now so the XLR for the right channel crosses the FP insert.
In our Condo system w TREO they also flank FP, equal length Kimber that will eventually get routed thru walls and under firebox.

IF you want to experiment in absorbtion inexpensively, I recommend 4 x 2’ x 2’ SONEX foam panels on a 1/4” Luan plywood backer.

have fun

I am sure Johnny R will have lots of input.

IF you do go equal length, do not create an inductor ( coil ) with the short side wire.....a large diameter coil Ok, loop back and forth is better ! 

I concur with Tomic. You should have no issues with the fireplace. If it is functioning properly, the heat should be mostly going up the flue.
I also agree in equal or near equal lengths of cable. The excess not coiled, as Tomic mentioned.
As far as hiding the cable in front of the fireplace, why not buy some of those cable conduits that allow you to walk on them? Not that you need to walk on them, but they would hide the cable in a discreet, visually appealing package.
Bob

I have 5A's that were in the same room as the fireplace ....all the lows flu away.....up, up and away....