Tweeter upgrade for Rt55i

billbill

I have an opportunity to buy some used Rt55i's which I would place in my secondary basement system as right and left speakers in a 5.1 setup. I like the dual 6.5 inch woofers which is very rare in modern day bookshelf speakers. I have read that this is a decent old speaker. However, I've also read that the metal tweeters make the highs a little tinny/harsh. Does anyone know if it is possible to replace the 1 inch metal tweeters in these speakers with some modern Polk silk tweeters (or any other brand tweeters)? If yes, would it be difficult?

vmaxer

No idea on the tweeters, but I have a set I bought new and love them. I would also be interested in upgrading them.

[Deleted User]

Actually the speaker's tweeter is a hybrid design, a vaporized metal deposit placed over a plastic substrate, called a 1" diameter "trilaminate". The thin metal coating worked to improve rigidity and reduce resonant nodes while the plastic acted to damp any ringing that could be a result in a purely metallic dome. It was that the company that made the complex dome no longer was able to produce them that caused a different tweeter to be developed.
Because of the uniqueness of the tweeter's mounting, being attached to the inside of the curved front baffle, I don't believe it would be easy to substitute a different tweeter. Plus the speaker's crossover was developed with that tweeter and drivers in mind.
I would suspect that associated electronics would cause any complaints of harshness or treble edginess. Put them with worthwhile equipment and use a little care in placement and they could be very satisfactory. Remember that they are very similar to the top half of the highly regarded RT3000p/RT5000p system.

[Deleted User]

You're welcome, I'm glad the information was helpful.

billbill

Kenneth, Thank You for your knowledgeable and informative response. I really didn't know much about trilaminate tweeters but you gave me a good explanation. I wish I could hear the sound before buying this well regarded speaker. Unfortunately you usually don't get to hear what you are buying from eBay the majority of the time. I will have to think about it some more.
Yes, it is the unique front baffle that is making me think that it would be difficult to substitute another tweeter. The existing crossover may also not work well with a different tweeter. So I have some thinking to do. If this speaker's woofer or tweeter blow, I may have a difficult time finding a replacement which makes me think twice about this purchase.
I do agree with you that electronics can cause harshness/excessive brightness. But some speakers have a reputation for being harsh or bright which means sometimes it's the design of the speaker. Although almost all of my speakers are Polk, I do have a pair of BIC DV62si's for my basement budget system. They are known to be harsh and fatiguing. But I had the famous Ed Frias crossover modification done to them and that reduced the brightness and made them sound a bit more natural.
Thanks again.