to the OP, I'd say in my case it's very, very short. OFC memory exists, in every form, and ofc those abilities vary per person, but as mentioned above, when forced, or wanting, to really concentrate on the task (as, maybe, during blind testing of several similar components) If the gap between the component audition exceeds a minute or so, then I was never quite certain that my memory of the sound...it's exact nature, was accurate. However if I wrote down my experiences (The Cello is positioned exactly in line with that curtain, and the sound has real timbre, sounding louder than the Violin just to its left) then I can compare better.
One can remember general character fine ofc...one amp warm, one cooler sounding etc, but precise details, not so much.