Problems with Infinity Prelude MTS mid-range

Has anyone else had problems with the mid-range driver on the Prelude MTS, (buzzing, dust-cap falling off etc.) I have now had three of the towers have issues, especially distortion with piano pieces.
I have 6 prelude mts's, have had extensive problems with the subwoofer amplifiers (5 of the 6 have needed repairs) I've also "blown" two midranges over 6 years, spiders detached from voice coil, possibly from being under-powered, rather than over-powered. The dust caps seem poorly attached on several drivers (poor fit), but don't buzz or rattle (other than "blown units" that the partially delaminated spider allows voice coil to rub in gap)Certainly not built with the "care" one would expect in this price range...
Haven't experienced problems with mine. But agree with Hhiggins that clipping will blow the midrange driver.
yes, i sold my mts preludes after replacing many of the drivers, mine also buzzed on piano music and after replacing the drivers i took apart the old ones only to find that the prelude drivers are faulty, the coating that infinity uses on the neo magnets starts peeling off with age and gets trapped between the voice coil and magnets causing the buzzing sounds that you hear, there is no way to repair them once they get like this, i replaced about 6 drivers in my towers and all of them had this same problem, although the 5.25 inch woofers are harder to detect the buzz sound as they are crossed over lower, but they also scrape or buzz, i called infinity and told them of the problem i was having and asked if there was a problem with this happening and of course the said no, they weren't going to tell me that they were faulty, i read about allot of other people that are having the same problems i was having, most of them thinking that they just lost a coil, boy if the only took apart the old driver they would be pissed to find that the magnets failed, as these speakers get older you will hear about it allot more, because IMHO the neo magnets are faulty as they deteriorate with age and peel,causing the buzzing sounds that you hear, too bad as i actually liked the sound of the speaker, what a joke i have a pair of 25 year old infinity's that have neo magnets and they are still like new, since Harmon took over infinity speakers went down hill, they really skimped out on the quality of neo mags used in the prelude.
i also had one of my subs go out for no reason at all, i never play my system loud so the subs were never pushed hard, they were working fine and the next time i went to turn on the system the sub did not work, had to send it in for repair, i never had any speakers before with so many problems as i had with the preludes.
Thanks everyone. If you are having problems please add to the thread. I'm going to keep pushing Infinity about this. They told me they get very few complaints about this speaker. That's insulting. Any one at Infinity is welcome to comment on our problems.
One of my 5.25 inch woofers is distorting.
One of the subs went bad and I sold the subs after it was repaired.

It's disappointing to hear this is becoming common as I was thinking of trying to get this 5.25 woofer repaired. I've been very pleased with the sound otherwise.

Yes, am having issues me-self.

I have a couple of the midrange drivers that are experiencing the buzzing you're referring to. Not sure if the voice coils have actually collapsed or if it's due to the peeling.

I was fortunate to have purchased quite a few replacement drivers and just take care of it myself. I know it's not from clipping or under driving my Preludes. I went with tons of clean power to prevent that from happening. I believe it to be a defect in the drivers.

Now I'm getting some really nice humming coming out of my subs. When you first turn them on they're fine. But, as soon as you send a signal to them... up comes the hum. Very annoying. Anyone else having this issue? Where did you send your Preludes to be repaired?

I was told to take them to a local electronics shop by Harmon. Don't know about you's but, here in WY, I'm not sure anyone would even know who/what Infinity is. Let me park my sheep first and then I'll take a look at your High-End Bose speaker-er!

I could repair the problem if I were able to have someone diagnose and tell me exactly which part's at fault. Use to build pc boards and can replace any and all electronics but I have no expertise on troubleshooting circuits.

Still love the sound reproduction from my Preludes. Running full range front and rears with the Prelude MTS for the Center Channel. Used to have a surround setup with Legacy's Focus and there's no comparison. I was really hesitant on powered subs but these have made me a true believer. Now if I could jut get rid of that annoying humming.


There is an authorized repair shop here in California, not far from me. I will see if he can give us some answers and post them here.

Still hoping one of you folks at Infinity will get in on the discussion. You are welcome anytime. I might like to point out that your competition checks in from time to time with some helpful answers.
I've had problems with the sub amps (have 6 prelude subs & 3 intermezzo subs,very similar amps) All but 2 have had the amps stop working, & one has hum issue. Repair shops have no incentive to repair, as reimbursement for warranty work is very low. I've rewired & using crown amps with a velodyne sms-1 to power/eq (also a few velodyne sc 1250's power amps)
I also have a problem with a distorting midrange when playing certain CDs (for instance Louis Armstrong, his voice sounds awful, and some rock CDs).
I have been playing them pretty as probably the former owner also did.
No problem with the subs, although they sound not as powerful as they should be, but maybe i am expecting too much.
A rep from Harmon said one could press on the cone lightly and listen for scraping sound, then press some more back and forth and the sound would get better for a while at least. I have not tried it. He didn't mention why the problem was there, but hinted at overdriving.
I don't know what to do, the info here makes me feel I might as well buy a new set of speakers (and keep the subs).
Any tips are welcomed! (I live in Europe.) The speakers sound really good when on a lot of material (jazz, classical).
According to this page, the 3.5 inch driver is no longer available!

What to do? Does anyone know of a similar speaker if one would try to replace it?
I'd look for an extra pair of towers for replacement parts, because you're not going to find a pair of speakers as good as the Prelude MTS for the price of an extra pair of towers.
Drivers are now available as of 31 OCT 2010 according to Harman page:

Anyone knows if these are better than the original versions?

I contacted the Swedish company that services Infinity (and JBL etc.) and amazingly they just had another MTS speaker in that had the same problem with thew 3.5" driver, sold at the same HIFI dealer as mine. The service man showed me the reason it sounded bad (same reason as stated earlier in this thread), and that it was clearly a manufacturing problem, probably due to magnetic material being present when they made the driver.
So he replaced both the 3.5" (left and right speaker) at no cost! "When you buy Infinity you should get good service, and these were faulty drivers from the beginning ..."
He had never come across this before and now he got two customers the same week!

Anyway, now that new drivers may be ordered you might as well have the speakers serviced if you have started to hear som buzz - it will get worse, believe me!


Thanks for the information. Hope the replacement 3.5's have the problem resolved. I will contact my dealer and see if he will do the same for me. As I live in the U.S. where the customer services the company instead of the other way around, I will probably have to replace the speakers myself. I have the complete surround system and two MTS w/ sub for a dedicated room. Every 3.5" driver has a problem now except one. Listening to a pair of Audioengine 2's instead of surround right now, and bought a pair of Dunlavy's for the dedicated room. Perhaps the New Year will find working Preludes again as they are excellent sounding speakers.
I have this problem with my midbass. Has anyone managed to repair them in a repairshop? (not infinity) Since i hear the problem is with some peeling, i thought maybe it could be cleaned, and thus repaired.

Has anyone tried/done this??
Well, I have Infinity Prelude Compositions since I think 2002, and I hope these problems don't crop up. I really like them a lot. They're especially good with low powered SET, better still if you can give them just a little more juice. The Cary V12 and Cary 300B are wonderful with the built in sub (25hz). The Primaluna Dialogue One I own also performs well, my brother's Leben CS660 is really a nice match. I always wondered why more people with moderate low-powered amps were not purchasing speakers such as the Prelude Compositions? These speakers cost about $3,400.00 back in 2002. Good luck solving issues, HK sucks for not owning up.
I change MTS for a pair of Tyler Acoustics D1 last year, GREAT DECISION. Didn't missed them.
They had more problems every day, first the mids, then one sub, then...
If you need spare mids or anything, let me know, I can sell them. The only problem is that I live in Ecuador and shipping will be expensive. I have 3 subs, 2 tower and a center speaker.

Does anyone know the part number for the 3.5" CMMD midrange driver and if they can still be purchased? I'm getting distortion during piano pieces on one of my towers.

Does anyone know if the midrange drivers can be repaired?

Too bad because I really like the sound of these speakers
I could look at mine but it doesn't really matter no one makes them or have any. Almost impossible to find. I have three
I‘ve got the problem with the neomagnet too and it’s pretty depress not to find one in the internet. 

But there is also another problem. Since I had to bring them to my new Appartement the Towers just play with one of the drivers. That’s quite strange. And in both towers the problem is the same. Just this one driver in the middle of each tower is working. 

Is there anybody having an idea what is wrong?

would be great to find help here
for a fix of infinity prelude MTS  have a look at they ship international.
Great site the also do complete rewinding.
Count another one. Most of the towers buzzing. One sub is out. Really bad that this should happen. They are such nice looking speakers too.
Yes they are.
And, when fully functional are amazing.

I contacted Bill @ Millersound, two weeks ago, and he says he can repair the delamitation issues plaguing the Infinity MTS' drivers.

As I have many sets of these Preludes... I'm in the process of finding and sending him two of my 3.5" midrange MTS drivers

May be worth a try if you like what these speakers provide.