Replacement Tweeter?

Good evening... first post here! I have a much loved pair of Genesis Genre 1's, getting on in years, purchased from Audio Advisor somewhere in 1994. They have been great, although per the advice of one of the Genesis tech's, I sent the midranges and woofers out to be reformed due to dried up glue. Nothing lasts forever, right? That was somewhere around 2005, and they have been pretty darn good. However (there's always a but, right?) they have sounded a bit off recently, a symptom that can best be described as "nasally". It seems to have been getting worse, although all of my friends think I am nuts. Tonight, I arrived home from work, very excited to toss in a new CD from Amazon, and the system sounds REALLY off... the right channel has no highs, and the midrange seems a bit muffled. I suspect the tweeter is cooked, and perhaps being part of the same circuit as the midrange crossover, has affected the output of the midrange. Where would you begin? I suppose I could swap the tweeters, and see if the problem swaps from right to left, or if something in the crossover is cooked. I am sad, kind of like when you favorite old shoes give up the ghost. I honestly think the loudspeakers are worth being repaired, any thoughts?