Longest Advisable Speaker Cable Runs?

Keep your amp between your speakers and purchase longer interconnects.

Hello. I manufacture cables and 30 ft. is not to long. It's dependent on the type cable used.
I'm not promoting my cables by any means. Just making reference that 30 ft. can be done.
I've made 75 ft bi-wires for a costomer that was very happy with the results.
Do your home work and find the right cable and you can do 30 ft. with no problem.
Hope this helps.

I would probably just recommend making sure you shielded cables with lower capacitance. With more details, you'll certainly get more specific recommendations, but in general, 30 feet isn't really a problem; it just means you'll have to be pickier about the cables you choose.

Look into Supra and OCOS cables. I have used both for runs of 18 ft. with no issues. The Supra can be purchased through
Sjofn-HiFi (get the shielded set). The cost and return policy make trying these very low risk. Not sure who is selling OCOS these days but they are considerably more expensive, unless you can track down a used set, and I don't know if any OSOS dealers offer a return policy.

Agree with Jazzerdave. A good quality cable will degrade the sound very little. We went from 8' to 20' ( same cable ) without any audible difference. We could probably go with 15' but then the cables would be visible.