Need Two Way Speaker Switch That Won't Negatively Impact Sound

There's no reason why a well designed, appropriately specified switch should degrade the sound. I don't know what commercial options there are but if you're willing to DIY then I'd just select a switch (or two) which is over rated for the voltage & current with gold contacts (silver if it's sealed). There's loads of choice but a quick search turned up this on Mouser as an example.

All mechanical switches degrade, period.

If you want the highest quality listening, switch the cables manually.

Putting a cheap switch with poor materials is a superb way to diminish sound quality.

@douglas_schroeder 

All mechanical switches degrade, period.

That's quite a blanket statement... what is the mechanism by which this degradation occurs?

Putting a cheap switch with poor materials is a superb way to diminish sound quality.

I don't really understand why something needs to be expensive to be effective... a silver contact switch is pretty much as good as it gets (maybe mercury wetted contacts are better). Gold is non-reactive so sensible if the switch isn't sealed as silver will corrode. Rubidium is entirely unnecessary unless your equipment is in a corrosive environment in which case you have other problems.

A switch is just a contact between two conductors like the contact between the cables and the terminals on the amp and speakers. As long as the switch is correctly rated and makes a good contact it should be fine. One advantage of inexpensive solutions is that they are easy to try for yourself.

No one is saying it won't work, but its presence will degrade the sound, whether it cost $500 or $5. You were told by authorities in the past, and I'm confirming it. If you don't wan to believe it, go get your cheap switch. Build a few hundred systems like I have, and you will have an opinion about it. :)

You can do it with a sealed high current relay which you can switch from your seat. I use one to AB loudspeakers but it is pretty old and I doubt it is still being made. Go to Digikey.com and search the relay section. You will need a small power supply to drive it, some wire and a push button STSP switch.