An Odd Question

Sympathetic Resonance is the issue. I have tuned guitars in the studio and then played forceful passages in the same room. What you hear after abruptly stopping is the stings and body of the guitars, violins and snare drums ringing due to the acoustic waves that are being produced and flowing/reflecting throughout the room. Similar to a slap echo you may produce by aggressively clapping your hands as you walk around and excite frequencies in the immediate space.

     Simple, just make sure nobody is playing any of them while listening and there will be no sonic impact.

That was easy,
      Tim

Wrong Tim. They resonate anyway. Not so easy after all.

I've never heard any notable change when I've had one of my acoustic guitars sitting on a stand as I played my stereo. True, sometimes the guitar boomed or buzzed a bit in sympathy but when it comes to tone or imaging emanating from the stereo, nothing. 

Sonic impact of having multiple (3) acoustic guitars on stands in your listening room?

To kill off most sympathetic resonances
Put a soft clamp across all the strings, and block off the sound hole in the bodies.

Cheers George