Dumb question..but just wondering ?????

I agree w/Rcprince about veneers and wood. Perhaps the question should be "what happens to MDF over time in terms of sound"

In my case although I have kept speakers for long periods of time I have always tweaked some part of the system so can't properly asses the issue. I am really curious to hear what others have to say though.

Prpixel is almost correct - cherry does darken over time - but it is photoreactive and therefore it is light, not age, which causes the color change.

As stated above, if your speakers are veneered then it is unlikely that the veneer would contribute to the 'sound' of the cabinets. If there were any solid hardwood panels then they may change over time, but I would suspect that the change would not be positive. If I remember correctly, the body of a string instrument is intended to resonate and, as such, contributes to the sound of the instrument. In the case of a loudspeaker, I don't think that the cabinet is supposed to 'participate' in the same fashion.

Perhaps more knowledgeable individuals will chime in.

The wood will darken with age, but the Formby's or whatever you use will accelerate the aged appearance. It should have no affect on the sound.

Ekistler,

I am aware that it's light that causes cherry to darken. Sometimes, when I build a piece out of cherry, I let it sit out in the sun for a few days to darken it; I hate using stains or dies.

Later,

Prpixel - I am sorry if I offended you, and I certainly didn't mean to insult anybody's intelligence (although I can understand why you might have interpreted my post in that fashion). I corrected your statement for the benefit of Garebear, who may have been thinking that the Formby's was responsible for the color change.

I have done a little bit of woodworking myself and I have always had very good results using Watco Danish Oil, typically applied with steel wool.