Replacement Tweeters for Polk rti12

A

Alexandre Bertrand

Audiophyte
Hi there,

I'm new in here but I was a big fan of hometheaters few years ago.

Few weeks ago friend came home to make some karaokee and the feedback from the microphone made the speakers 'scream' for a second or two. One of the crossover is gone (polk sell me a new one) and the two tweeters are dead too.

The original tweeters (which I can get from polk at 90$ usd a piece) are not really interresting to me. I like the rti12 but they were always too 'bright' for my liking. They are powered by a behringer '500 watt rms' pro amp.

I saw a suggestion for some 'tang band 25-17119s' somewhere. I've got an avr that let me adjust alot of the freqency thing. I need it to 'merge' with the polk cs5 center and if possible get and more laid back but still detailed sound from the two big polk tower


rd0697-1 1 inch tweeter is all polk let me know about their product. I think I read somewhere the the fs was around 800hz? no sure on that though


polk doesn't seems to want to help me out with this and i really need to make a move now
any suggestion? i never clip the signal beside that microphone feedback time, but i still need them to play as loud as they can with the behringer pro-amp configuration
 

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Swerd

Swerd

Audioholic Warlord
Welcome to Audioholics Alexandre. You didn't actually ask a question, but I assume you meant to ask if replacing the dead Polk tweeters with the Tang Band 25-17119 tweeters will work.

The short answer is no, it is highly unlikely that the Tang Band tweeter would substitute for the Polk. More is involved than than the resonance frequency (Fs) and size of the face plate. The crossover from the mid range drivers to the tweeter was custom designed by Polk for that combination of drivers. Unless the Tang Band tweeter is identical in performance to the Polk tweeter, a substitution will change the performance of your speakers. Whether it sounds better or worse is unknown. $90 each is a high price for the Polk tweeters, but unless you find them cheaper somewhere else online, its less than replacing your speakers.

For what its worth, I looked online and found these Polk tweeters at $40/pair. The description says they work in the Polk RT speakers, including the RT5, RT10 and RT12.

Parts Express sells Tang Band drivers including the 25-1719S tweeter. Is that the same as the '25-17119' that you mentioned? Look closely at the dimensions of the face plate. Is it the same as on your speakers? One of the customer reviews said "Great tweeters. I use this to replace the tweeters of my Polk Audio Rti12 towers, (one went bad) and this ceramic tweeter are smoother. The sound is more balance, and the detail is still there. The original Polk tweeter were in my opinion bright." I don't know whether this person understood what he was doing or not.

If you think your speakers sound 'bright', making it less bright sounding may be as simple as adding a 1 or 2 ohm resistor between the plus terminal of the tweeter and the wire running to it from the crossover. That should work better than trying to alter the sound with the AVR tone controls. Of course, you need working tweeters to do that.

It is unusual (but not impossible) that a crossover got fried by your friends karaoke mishap. How do you know one of the crossovers is dead?

In the future, don't let friends plug a microphone into your system. A microphone will always pick up sound from nearby speakers, and feedback will result. Home audio speakers were not made for that.
 
Last edited:
A

Alexandre Bertrand

Audiophyte
Hi Swerd, thanks for your feedback

It seems like the tweeter in the 40$ link you gave me works with the RT line , which doesn't seems to match the RTI line (mine has 3 7inch woofer, 2 5.5inch mids and the blown tweeter)

I did the 'defect crossover' deduction from a test with other tweeters and a multimeter (sp?) no signal reach the tweeter no matter what i send but the rest of the speakers works well.

as far as the Tang Band part, I just wished that the guy was a professional or extremely competent DIY sound guy. As i can't even get the technical information from polk, i guess that just buying them a putting them in place of the other might be risky.


The part i'm looking at rd0697-1 doesn't seems to be sold online beside the technical guy from polk customer service in canada (outragious price)

I'm just stuck there. I did have the center that match the overall 'timbre' of the tower set, so i just can't put anything in here without knowing how the overall sound will be past the pioneers calibration system
 
Swerd

Swerd

Audioholic Warlord
It seems like the tweeter in the 40$ link you gave me works with the RT line , which doesn't seems to match the RTI line (mine has 3 7inch woofer, 2 5.5inch mids and the blown tweeter)
I misread those speaker names. RT12 is not the same as RTi12. I'm sorry for the mistake.
I did the 'defect crossover' deduction from a test with other tweeters and a multimeter (sp?) no signal reach the tweeter no matter what i send but the rest of the speakers works well.
That does seem like a blown crossover part. Usually a resister burns before a capacitor or inducter coil fails. If you can see the crossover board (you'll probably have to remove a woofer), look for a part that appears charred or blackened. However it may be difficult to identify a failed part by it's appearance alone.
as far as the Tang Band part, I just wished that the guy was a professional or extremely competent DIY sound guy. As i can't even get the technical information from polk, i guess that just buying them a putting them in place of the other might be risky.
That was my thought as well. Just looking at the Tang Band tweeter picture at Parts Express, it didn't look the same size as the tweeter in the photo you posted. Will it fit? See the dimensions here http://www.parts-express.com/pedocs/specs/264-865-tang-band-25-1719s-specifications-45762.pdf
The part i'm looking at rd0697-1 doesn't seems to be sold online beside the technical guy from polk customer service in canada (outragious price)

I'm just stuck there. I did have the center that match the overall 'timbre' of the tower set, so i just can't put anything in here without knowing how the overall sound will be past the pioneers calibration system
Is your center speaker also a 3-way like your RTi12 towers? If so, the overall timbre is mainly due to the mid range and is less due to the tweeter. I wouldn't worry about that.

I think you have only three choices:
  1. Replace the Polk tweeters
  2. Gamble and try the Tang Band tweeters (if they actually fit)
  3. Replace the tower speakers
If it were my choice, I'd do the first.
 
A

Alexandre Bertrand

Audiophyte
Guess i won't have the choice beside the option one.

And the 'bracket' that comes with the tweeters seems pretty unique, so to make sure i keep the original look, i'll just bit the bullet and pay the price polk ask for


thanks for the help,

drunken karaoke night have their cost i guess :S
 
j_garcia

j_garcia

Audioholic Jedi
Option 4 - ebay or CL another pair of these. Picking up a used pair of those speakers would give you parts to repair them at least once (or keep those as the parts speakers). I would honestly choose option 3 and replace the center too as a total solution.
 
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