Need Long Length Speaker Cables

You guys are wrong, he won’t lose anything as long as he goes with a 12 gauge cable. Canare 4S11 speaker cable which is 11 gauge will run you less than $2.00 a foot plus termination from Blue Jeans Cable.  You  are probably looking at around $300.00 and they will sound as good as speaker cables costing $1K. 

No doubt you will lose a little but if you have a beast of an amp you may be ok. 45ft isn’t crap in studios or live performances. If you can’t set your amp closer and use long XLR cables back to preamp then look at Canare. Unless you have Golden Ears you may not notice the difference regardless. Top end may get a little rolled off but I’d be more concerned about them working as antennas and picking up a lot of EM/RFI which is why I’m throwing out Canare as it is very good at canceling out noice being it’s primarily used in studios and pro audio. Canare 4S11 is a good cable regardless of cost. 

IMO, running long XLR interconnects (if the upstream kit is diff balanced) is a superior option. If your kit is not, then consider going that route first
hth

45Ft you will loose sound quality for sure.

I have used Supra for long runs and has worked well.

https://www.ebay.com/itm/154301399329?hash=item23ed148121:g:624AAMXQLQVR62Lf

Also DH Labs.

https://silversonic.com/products/bulk-wire-and-cable/bulk-speaker-cable/prelude-11-awg-speaker-cable...