1132 drivers and when is a diaphragm too old?

[Dave A]

I buy used gear and so rarely get to hear what new Klipsch is capable of. I have read about diaphragms in K-55-V's needing refreshing but have never done so since they ohmed OK and seemed to pass frequency sweeps fine too. I had rebuilt an LSI beater into a two piece recently and used the K-55-M drivers for the mids. They were shrill enough that it was clear something was wrong and since I had put new large MAHL tweeters in there I knew it had to be the mid drivers. So I grab a set of K-55-V soldered lug's and set them in there and it sounded great. At $80 a pop for diaphragms to redo these old mids though if they are that bad I think I would rather just spring for new Atlas drivers at $100 more for a new set that will last my life time. And I assume there have been improvements made along the way as a plus.

 

  Improvements along the way is why I am posing today. I have run through 9 sets of KPT-456's which have used the 1132 drivers and also put those on my 402 horns on the S-MWM. They sounded good in all cases. I had a chance this week to listen to these same drivers with current phase plugs and new diaphragms and the difference was NOT subtle. All things being equal and nothing touched when I fired these up it was pretty shocking. I have no idea what the life span is of diaphragms but I am having to rethink the idea of good until they fail. The other part of the equation here is how these were installed. I did not install these but recently I had a set of Ti diaphragms to put in a set of K-792 tweeters and one sounded good and the other did not until I aligned it using a frequency sweep generator. I had these in a set of KP-250's and don't like them at all by the way. WAY to shrill and soon to be EBay bound. And the last part is what difference exactly can I attribute to the new phase plugs? Maybe 90% was due to them and I have no way of determining that.

 

  What I can say is considering the difficulty in finding 402's and the difference between the old 1132's and the new ones I think if I were to do this over again I would buy the new gear from Klipsch and be done with it. Sitting in the shop today and thinking how nice things are sounding as all the pieces come together and get dialed in. I am very close to the point where I can be happy with what I have and not seek for more because I don't feel my system is up to snuff. Then something like this 1132 episode pops up and I wonder what else am I missing?

 

   

[mark1101]

If you decide to replace the 1132s I would look into 691s.  Not expensive and the benefit is that you can pop Roy's settings into the Xilica and be done with it.