I think I agree with TLS Guy's criticism, even though I also agree with what the original poster wants to try. I've always advocated that people compare speakers' sound qualities, not their looks or price tag. Usually most people do that kind of rigorous comparison before they buy speakers, not afterwards. It must be a case of
Audio Nirvana Nervosa more serious than mine, to keep comparing speakers you already own

.
There is such a switching device, but at $1,400 it ain't cheap. That's the price these days to indulge
Audio Nirvana Nervosa. This device can safely switch among as many as 3 pairs of speakers, using high-powered amps. It also allows switching of up to 2 preamplifiers and 2 power amplifiers. It has a remote control, and allows the listener to precisely adjust volume levels to match within 0.1 dB.
I once had my hands on this item. When Dennis Murphy displayed his different Philharmonic Audio speakers at a local audio show, he also used pre-amps & amps borrowed from Audio by Van Alstine. Frank Van Alstine also threw in this switch/comparison device for the show. It worked well. But to be honest, I don't know anyone who wanted to buy one.
Due to high demand we have produced another run of our ABX Switch Comparator. This unit allows seamless switching of up to two preamplifiers, two power amplifiers, and three sets of speakers either with or without subwoofers. The AVA ABX Switch can be used to evaluate cables and component parts...
avahifi.com