HOW TO POSITION 2 PAIRS OF SPEAKER FOR ALTERNATE LISTENING

The biggest problem is that you may want each pair of speakers in the same location in the room when being listened to. Better to put the unused pair in another location in the house. If the unused pair must be in the room, short the speakers by running jumpers from positive to negative terminals, and cover them with a blanket.

@stfoth  Can't respond about hearing an audible impact.  The only time I've experienced multiple speaker pairs in the same room is at a dealer's and they are not usually interested in moving other speakers out of the room to accommodate to a customer unless serious $ is at stake.

i have 4 bose 901 speakers i bought back in 1971. at that time bose had a system that was called 'the super bose system' anyway you would have the 2 speakers up front and the other 2 on both sides to bring the soundstage out.to the left and right.

The place where the second pair will have the least impact is behind the first pair. Turntables. I know of one shop that employed this solution before they moved. 

I have to give you an answer you won’t like, but such is life. If you want a True, accurate sound comparison anything done to keep the speakers in the same room at the same time simply for convenience is a compromise therefore you will not get a true comparison. It’s a pain in the derriere but you must move one pair of speakers out of the room and set up the other pair properly, listen to them, get accustomed to them, take them out and do the same with the second pair. Never Promised You a Rose Garden. Sometimes this hobby sucks but there it is. I will add one caveat if you're not dealing with a critical listening pair of speakers or system and it is not that important to you to have a true accurate comparison in it and it's just background music then who cares probably doesn't matter a bit. you didn't mention the type of speakers or system you were using so all this maybe for not. Just saying.