Fuzzy Noises

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djbrettbsu
djbrettbsu Posts: 3
edited November 2003 in Troubleshooting
I just inherited a pair of vintage RT12's purchased back in '96 by my parents. They sound great as they did the day we bought them. However, at a LOW volume, I notice an extra noise, almost always along with the midrange of the listening spectrum... namely male voices. The sound resembles the noise a kazoo makes. Only not as forceful. It just is there... along with the vocals. Not overpowering at all, but still a bit annoying while listening at low levels. I figure it may be a driver problem. Or maybe a crossover. Maybe even my Sony STR-D915 receiver? I'll try a pro audio amp on them and see what happens in the meantime. Any suggestions?

-Brett Williams
Email me directly or post to this thread! Thanks!
Post edited by djbrettbsu on
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  • ken brydson
    ken brydson Posts: 8,650
    edited November 2003
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    Hi Brett-
    First off, welcome to the forum. Lots of good info to be had here. To your problem. I had a similar issue with my LS50's. It turned out to be a bad driver. See if you can locate first, which speaker it is and second, which driver. If you can isolate the driver, pop it out and check the wiring for loose connections. If they seem ok, disconnect the driver and see if you still hear any issues with any of the others. If not, trying swapping a working driver from the other speaker to rule out a c/o problem. If it sounds ok then the driver is shot. Replacements can be purchased from Polk. Make sure you mention you're a Club Member and you get a 20% discount + free 2 day shipping. I am by no means one of the forum experts. Some others will probably post other suggestions.
    Good luck!

    EDIT- I should have mentioned the most obvious first. If you haven't already, check all the speaker connections. Make sure they are secure and there aren't any frayed wires possibly touching the other wire or post.
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  • djbrettbsu
    djbrettbsu Posts: 3
    edited November 2003
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    Bryd-

    Thanks for the welcome. I will take action given your suggestions.

    In the meantime, I hooked the speakers up to a signal from my computer and played pure sine waves at different Hz levels... and was easily able to figure out which drivers were making the noise. After removing the drivers from one of the speakers, I pushed lightly on the cone... on the good-sounding one, no resistance, no noises. On the funny-sounding one, resistance, a rubbing sensation... as if the cone was rubbing on something.

    I'm afraid the only remedy to the problem is replacement. I imagine the way the driver got this way was being overdriven to distortion... the STR-D915 is only 110 watts per channel... but I can hardly believe that it is CLEAN PURE power. Hooked up to a Mackie amp, I'm sure I could drive these RT12's with 400 watts and not have a problem just as long as I didn't get any distortion.

    Thoughts? The driver's blown?



    -Brett
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  • ken brydson
    ken brydson Posts: 8,650
    edited November 2003
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    Sounds good. Keep us posted. I looked up the club price on the MW7010 driver and it's $60.
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  • djbrettbsu
    djbrettbsu Posts: 3
    edited November 2003
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    I just totally changed that post from before, while I was editing you posted again!
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  • dorokusai
    dorokusai Posts: 25,576
    edited November 2003
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    Bad driver. That's a nice speaker, get that puppy replaced and start rocking the house again :)
    CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
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