Some weird sound grnn grnn coming from subwoofer when increasing bass

valechadeepak
valechadeepak Posts: 11
in Customer Service
Hi I have Polk Subwoofer PSW12 and it's making weird noise of grnn grnn when I increase the base woofer is good nothing is lose I have checked the connection but still sound is there can you help me out with the problem I love the woofer sound but because of the weird noise I can't enjoy fully
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Answers

  • treitz3
    treitz3 Posts: 19,243
    Hello and welcome to Club Polk. That sounds to me (based upon what you have described) like a mechanical failure. Try moving the woofer in with your hand. Do you feel any kind of grinding, scratching or obstruction at all, or does it glide in and back out unhampered/smooth as silk?

    Also, double check all of the connections between the amp and the sub. Make 100% sure that they are not worn and a solid connection is made. This includes the signal and power cables.

    Tom
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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  • valechadeepak
    valechadeepak Posts: 11
    Hi
    I have checked all connections before and nothing is loose I have an amplifier Denon AVR 4306 which is a good amplifier only it's a sound coming from subwoofer,woofer is good nothing loose connection also good nothing lose and the floor is wooden,but still a grnn grnn sound coming from subwoofer
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  • treitz3
    treitz3 Posts: 19,243
    Try moving the woofer in with your hand. Do you feel any kind of grinding, scratching or obstruction at all, or does it glide in and back out unhampered/smooth as silk?

    Tom
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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  • valechadeepak
    valechadeepak Posts: 11
    Yes smooth as silk but the sound is there
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  • valechadeepak
    valechadeepak Posts: 11
    I can send the video of noise
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  • treitz3
    treitz3 Posts: 19,243
    That may prove to be very helpful in this situation. Please do so.

    Tom
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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  • treitz3
    treitz3 Posts: 19,243
    One further thought.....have you verified that something internally within the sub has not come loose?

    Tom
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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  • mhardy6647
    mhardy6647 Posts: 34,019
    perhaps the surround is failing? This may or may not show itself in the "fingertip test". :|
    Yes, to echo @treitz3, we eagerly await some audio of the problem!
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  • valechadeepak
    valechadeepak Posts: 11
    Yes i have checked subwoofer internally and the connection box internally subwoofer is good although not sure about box internally
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  • mhardy6647
    mhardy6647 Posts: 34,019
    edited January 14
    Come to think of it -- and with apologies if I missed this earlier! Did you check for loose screws?
    The self-tappers that secured the woofers in my old (and long-gone) Klipsch Cornwalls used to work themselves loose over time, with audible consequences.
    Jennifer Warnes' infamous track Way Down Deep was my standard assay for this, FWIW. ;)

    https://youtu.be/dbxkbSfOVZc?si=mobjSqqkzMdkng60
    probably not enough audio resolution to do the track justice. :)
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  • valechadeepak
    valechadeepak Posts: 11
    https://youtube.com/shorts/52TTsp5DVbE?si=WbW_Ewwf-xxGsiPK
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  • valechadeepak
    valechadeepak Posts: 11
    Please check out the video you will understand the sound I'm talking about
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  • treitz3
    treitz3 Posts: 19,243
    edited January 14
    That sounds like you have burned the voice coil in one or more areas. Are you sure (sub powered off) that you don't feel any scraping or obstruction, (no matter how slight) when you press in on the woofer?

    szmxvlpt4sw7.png

    What I would suggest it to take out the woofer and test it independently from the body of the cabinet. Do you still hear this noise? If so, it is the burnt voice coil. Smell, to see if there is any kind of burnt smell, or abnormal smell to the woofer coil. If any of this is detected, then you need a replacement woofer.

    Alternatively, it *may* just be something internally within the sub itself that has worked itself loose, and is resonating with the frequencies (I doubt it but it won't harm anything to check).

    Tom
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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  • mhardy6647
    mhardy6647 Posts: 34,019
    edited January 14
    Excellent! We've got 'em sniffing voice coils! B)
    Sorry, couldn't resist. :/
    @treitz3's suggestion is likely spot on. It is known in some circles as cr@p in the gap. should be fairly easy to feel, as he suggested.
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  • valechadeepak
    valechadeepak Posts: 11
    Well I checked woofer and it's not smelling burnt so what's the solution now
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  • HzTweaker
    HzTweaker Posts: 793
    Check and see if the spider is detaching from the voice coil?
    2ch rig: Speakers: Magnepan LRS w/Magna Riser stands Preamplifier: Parasound P5 Amplifier: Parasound A23 CDP: Pioneer DV-563A Cables: Wireworld Equinox 7 XLR ICs, Wireworld Ultraviolet 7 USB, AudioQuest Q2s, AudioQuest NRG X(preamp)

    Standby: LSi9s with VR3's Fortress mods
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  • treitz3
    treitz3 Posts: 19,243
    While you have it open, take some snapshots of the coil, magnet and wires. Even if you don't think it would help. Take them anyway and please share them with us. Thanks.

    Tom
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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  • valechadeepak
    valechadeepak Posts: 11
    I have opened subwoofer not the woofer
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  • pitdogg2
    pitdogg2 Posts: 25,728
    edited January 14
    valechadeepak wrote: »
    I have opened subwoofer not the woofer
    I sure he's speaking about taking pictures of the woofer, not taking the woofer itself apart.
    Pictures of the voice coil wires going to the cone itself and all aspect views of the actual woofer.
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  • mhardy6647
    mhardy6647 Posts: 34,019
    HzTweaker wrote: »
    Check and see if the spider is detaching from the voice coil?

    Since I last dropped by this thread, I had got to thinking about a sagging spider, too!
    Again, some photos of the driver (i.e., the woofer) could be very helpful.

    One other thought -- does anyone know if the suspension on this particular woofer tends to sag? I kind of doubt it, and I reckon that the "fingertip test" would have probably demonstrated some voice coil dragging if there were some gravity-induced sag going on... but when sag is a problem, sometimes removing the driver and rotating it 180 degrees can help, or even solve, the problem.


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  • mhardy6647
    mhardy6647 Posts: 34,019
    edited January 14
    Just spent some time listening to the video... that sounds like some sort of resonance. Do the dustcaps on these ever tend to come unstuck (or is it one piece with the cone)? Or perhaps the surround is separating from the cone? I am leery such things, which are known to occur with plastic cones and dustcaps.

    If it were my subwoofer, I'd try some very gentle finger pressure on the driver while it was playing to see if the buzz could be mitigated. I am loath to recommend this to the OP, only because it requires a deft and gentle touch. Pushing too hard or unevenly while the driver is being driven could result in some damage -- and I am not about to own that risk! ;)
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  • treitz3
    treitz3 Posts: 19,243
    Oh, but you went there!!!!

    Tom
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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  • mhardy6647
    mhardy6647 Posts: 34,019
    I planted a seed.
    The fertility of the soil is not my responsibility.
    :D
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  • Viking64
    Viking64 Posts: 7,165
    mhardy6647 wrote: »
    Some photos of the driver could be very helpful.

    Does the suspension . . . . tend to sag? The "fingertip test" would have probably demonstrated some gravity-induced sag going on... but when sag is a problem, sometimes removing the driver and rotating it 180 degrees can help, or even solve, the problem.
    Here's a photo of the driver.

    Do you recommend rotating the driver 180 degrees BEFORE the "fingertip test"?

    f8a0budhsyco.jpg

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  • treitz3
    treitz3 Posts: 19,243
    So far, we have a video. No photos.

    We need more pics!!! (Otherwise, you are on your own), unless some schmuck decides to chime in...

    Tom
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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  • valechadeepak
    valechadeepak Posts: 11
    I have tried yesterday Finger pressure but still same.but yesterday listening it the sound was reduced and bass was playing well but sound is still there
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  • valechadeepak
    valechadeepak Posts: 11
    Hi
    I change the woofer I have other subwoofer brand Kef 10" I change it and tryed to see if it was woofer problem but it's not woofer problem it's something in box
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  • skipshot12
    skipshot12 Posts: 1,229
    edited January 16
    There’s something vibrating with or in the enclosure.

    Not sure this may help but…..
    I purchased a pair of brand new Infinity Kappa 8 speakers many moons ago.
    When certain frequencies were reached my left speaker had a buzzing noise.
    I tightened everything and no help.

    One day I removed the woofer to have a look around. What I found was one of the rivets holding an inductor, on the crossover, was never installed. It was vibrating on certain Enya songs.
    I mixed up some metal set and cemented that side of the inductor to the crossover and BAM, the buzzing was gone.
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  • msg
    msg Posts: 10,299
    mhardy6647 wrote: »
    I planted a seed.
    The fertility of the soil is not my responsibility.
    :D
    Stealing this!
    I disabled signatures.
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  • Viking64
    Viking64 Posts: 7,165
    msg wrote: »
    mhardy6647 wrote: »
    I planted a seed.
    The fertility of the soil is not my responsibility.
    :D
    Stealing this!

    LOLOLOLOL You're stealing his seed. LOLOLOLOLOLOL
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