Problem with midbass speaker in Prelude MTS Tower

I have a pair of Infinity Prelude MTS speakers and one of the midbass speakers in the left tower buzzes during certain songs when a cd or record is played. Does this speaker need to be replaced? I can't see any tears in the cone itself.
Can these speakers still be purchased? Any suggestions would be greatly appreciated.

Your suspicion that the midbass driver is blown may be well founded. I had tweeters replaced in mine recently, so I guess parts are still available.
I've had the same issue, usually with loud piano passages. Others on the forum have stated similar problems usually with the 3.5 midbass. I have contacted Infinity several times and get the usual "we don't receive any complaints about that speaker". Guess I will try snail mail. You can try this link, it looks like they have parts.
Hey, has anyone managed to get the mid bass repaired? I mean repaired in a audio repair shop, not at infinity/harman.

These are excellent speakers, my mid bass broke down now, and i was just wondering if it would be easiest to give some audio repairman them.
It should be easy to replace the bad driver, but you can't repair it.
I have 9 mids for the MTS, 3 subs and 3 tweeters available for sale.
I live in Ecuador, so shipping will be expensive, but if you want, I can get a quote.