rti a9 crossover fried

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tj1855
tj1855 Posts: 5
in DIY, Mods & Tweaks
edk9mf7747hz.jpg
Bought a pair of Polk Rti A9's about 3 years ago. Never had any issues until now. Noticed that listening to music, they sounded dead. While watching movies, they sounded great. Ran them 2 ch stereo and noticed that the tweeters were dead. Swapped in a dif tweeter from surrounds and still dead. Called crutchfield and, since they were still under warranty, they sent new crossovers. They actually wanted to send a new set of speakers!!!, but I was not ready to pack these monsters up to ship back. Long story short, this is what I found after removing x-overs. Obviously the white component, which is discolored and cracked is the problem. Can anybody tell me what this component is?
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  • stevep
    stevep Posts: 365
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    Sand cast resistor.
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  • tj1855
    tj1855 Posts: 5
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    So by looking at it, does it look terminal?
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  • stevep
    stevep Posts: 365
    edited November 2020
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    From looking at it, all I can say is it's clearly broken and highly suspect, from a little google usage it seems that it's happened before to others. I'd get the multimeter out and measure it and check the tweeter too cause it seems to be a coin toss if the resistor failed first and saved the tweeter or took it with it.
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  • pitdogg2
    pitdogg2 Posts: 27,765
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    I've seen worse. Too much volume not enough power to get there...
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  • F1nut
    F1nut Posts: 52,294
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    Noticed that listening to music, they sounded dead. While watching movies, they sounded great.

    With no tweeters playing I'm not sure how it's possible for movies to sound great.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • F1nut
    F1nut Posts: 52,294
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    pitdogg2 wrote: »
    I've seen worse. Too much volume not enough power to get there...

    Yep, drove his AVR into clipping.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • tj1855
    tj1855 Posts: 5
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    for what it's worth, I'm running an Onkyo TX RZ810 for surrounds and center. From there I run pre outs to Crown XLi 1500 for mains.
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  • tj1855
    tj1855 Posts: 5
    edited November 2020
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    As far as sounding good for movies, I have 3 other speakers that have good tweeters to compensate.
    Post edited by tj1855 on
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  • F1nut
    F1nut Posts: 52,294
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    Apologies for my AVR assumption.
    tj1855 wrote: »
    From there I run pre outs to Crown XLi 1500 for mains.
    Features: For PA System, Rack Mountable

    Pro amps do not belong in the home.

    Resistors get hot and when they get too hot they can crack and/or fry. Usually when crossover resistors get too hot it's a result of the power source sending clipped signals. Since your other speakers were not damaged the logical conclusion would be the Crown was clipping.

    Even with the other speaker's tweeters working it should have been obvious something was off.

    The good news is the damaged resistors can be replaced. You'll find the values printed on the body.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • tonyp063
    tonyp063 Posts: 1,154
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    I would also look long & hard at that cap next to it.
    They don't love heat
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  • F1nut
    F1nut Posts: 52,294
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    Good eyes Tony, it definitely looks bad.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • Hansvelton
    Hansvelton Posts: 151
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    F1nut wrote: »
    Noticed that listening to music, they sounded dead. While watching movies, they sounded great.

    With no tweeters playing I'm not sure how it's possible for movies to sound great.

    You beat me to that comment for sure~! A logical conundrum!
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  • joblo
    joblo Posts: 9
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    I have the same problem. one of the 2 resistors fried on one Rti a9 tower. Its powered by a Rotel RB-1590 which is quite powerful. There's 25 feets wiring from the amp to that tower, could be caused by that?

    I will change the resistor. Should i use the same type or resistor or anything with the same specs (5W2ΩJ) will do the job? I did some researchs and those ceramic resistors are the cheapest available, installing a better resistor will improve the sound?
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  • la2vegas
    la2vegas Posts: 768
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    tonyp063 wrote: »
    I would also look long & hard at that cap next to it.
    They don't love heat

    No need to look too long at the questionable cap as the OP stated that he is getting a new crossover from Crutchfield. I would believe that Crutchfield would replace the entire crossover, not simply the cracked resistor.
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  • pitdogg2
    pitdogg2 Posts: 27,765
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    joblo wrote: »
    I have the same problem. one of the 2 resistors fried on one Rti a9 tower. Its powered by a Rotel RB-1590 which is quite powerful. There's 25 feets wiring from the amp to that tower, could be caused by that?

    I will change the resistor. Should i use the same type or resistor or anything with the same specs (5W2ΩJ) will do the job? I did some researchs and those ceramic resistors are the cheapest available, installing a better resistor will improve the sound?

    I would up the wattage to 10 or 12 watt same 2 ohm value. The larger wattage value will help dissipate heat better. Vishay/Mills or Mundorf are good bets.
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  • joblo
    joblo Posts: 9
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    Thx alot! Ill follow your advice. Vishay/Mills dont have the resistor in stock. The Mundorf dont have 2 ohms. Should i go with 1.8 or 2.2 ohms?
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  • westmassguy
    westmassguy Posts: 6,850
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    http://www.soniccraft.com/product_info.php/ohm-mills-mra-12-p-683
    http://www.soniccraft.com/product_info.php/ohm-vishay-mills-mra-12-p-5330
    Home Theater/2 Channel:
    Front: SDA-2ATL forum.polkaudio.com/discussion/143984/my-2as-finally-finished-almost/p1
    Center: Custom Built forum.polkaudio.com/discussion/150760/my-center-channel-project/p1
    Surrounds & Rears: Custom Built forum.polkaudio.com/discussion/151647/my-surround-project/p1
    Sonicaps, Mills, RDO-194s-198s, Dynamat, Hurricane Nuts, Blackhole5
    Pioneer Elite VSX-72TXV, Carver PM-600, SVS PB2-Plus Subwoofer

    dhsspeakerservice.com/
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  • joblo
    joblo Posts: 9
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    Thank you!
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  • joblo
    joblo Posts: 9
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    In case changing the resistor dont work, someone know where i could buy the rti a9 crossover?
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  • la2vegas
    la2vegas Posts: 768
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    joblo wrote: »
    In case changing the resistor dont work, someone know where i could buy the rti a9 crossover?

    They pop up on Ebay every so often.
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  • joblo
    joblo Posts: 9
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    Thank you!
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