Tinny sound accompanying cello on recordings ?

I'm somewhat baffled by an on and off tinny sound I've heard on several recordings of Dvorak's Cello Concerto. Up until a few years ago, I either didn't hear it or didn't notice it. The more revealing the sound system, the more obvious is this phenomenon. At first, I thought something was wrong with my speaker drivers, but when I listened through other transducers, I noticed the sound was still there. I proceeded to isolate the rest of my equipment, but the rather unwelcome "guest" remained. It didn't matter whether I used the same recordings with a cd player or a phono front end, things didn't vary. I listened to identical passages of the Dvorak Concerto with Fourier/Szell and Harrell/Levine. I haven't yet bothered to check other cello recordings. This tinny/sizzling sound is a shadow-like resonance hovering around the cello's notes as they are being played, asserting its presence more frequently, it seems, from the mid to upper midrange. I assume some of you classical fans have heard this. Can anyone explain exactly what's going on here ? By the way, I hear it also (though less obviously because of the much smaller sized sound system) when watching and listening to the same piece performed by Rostropovich on You Tube with my computer and its little Altec speakers. Listen in particular to the first movement from the time the cello enters, and onward.