MW7011 magnet shift

ChrisD06
ChrisD06 Posts: 929
in Speakers
Apparently solid metal drywall anchors suck. Just kidding, the drywall literally ripped apart and now there is a giant hole in my wall (2, actually, one from my fist).

RT35 magnet shifted. It's REALLY bad. Completely locked up and the coil seems like it's been pushed up as far as it goes. Can I remove the magnetic shielding or is this practically impossible.

I know the coil is probably destroyed, but I'd at least like to see how bad the shift is. If anyone wants this driver for some odd reason you can have it for shipping.

The cabinet damage is a whole other beast... can't believe this, super upset right now.

ac6wb3gt94ib.jpg

The spider isn't even stretched evenly all around, and the wires to the coil are tight like guitar strings. I think the coil is toast 🥲
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Comments

  • F1nut
    F1nut Posts: 50,643
    Ouch
    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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  • ChrisD06
    ChrisD06 Posts: 929
    It still plays high frequencies and the coil tests ~2.8 ohms on my multimeter, and my spare MW7016 does too.

    I have the MW7016 in there now, but I'll get a 7011 just so it's a 1:1 replacement.

    If anyone knows how to pop the shield off then please do tell.

    Also, I agree with you F1, it's a big ouch
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  • xschop
    xschop Posts: 5,000
    4" angle grinder transversely cutting the shroud. Just be careful of depth when you're near the magnet OD's. Can't believe it shifted with that shroud. It basically locks the magnet and pole-piece from doing so.
    Don't take experimental gene therapies from known eugenicists.
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  • ChrisD06
    ChrisD06 Posts: 929
    xschop wrote: »
    4" angle grinder transversely cutting the shroud. Just be careful of depth when you're near the magnet OD's. Can't believe it shifted with that shroud. It basically locks the magnet and pole-piece from doing so.

    Dude I can't believe it either. It hit the ground HARD, like 20 lbs speaker falling 5 feet right on the corner.

    I'm just glad that, other than the woofer and pretty nasty corner damage (cosmetic, no biggie, I'll just fix it myself with $5 and patience) the RT35 itself is fine. In other news, I just bought a second pair for $110 shipped in flawless condition for my 9th channel!
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  • xschop
    xschop Posts: 5,000
    edited July 2023
    Set it up on flat table and check flange distance to table each side. @gp4jesus sent me his RTiA drivers. One got damaged in shipping like yours, cocked the coil, although magnet didn't shift because shroud held tight.
    Don't take experimental gene therapies from known eugenicists.
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  • ChrisD06
    ChrisD06 Posts: 929
    xschop wrote: »
    Set it up on flat table and check flange distance to table each side. @gp4jesus sent me his RTiA drivers. One got damaged in shipping like yours, cocked the coil, although magnet didn't shift because shroud held tight.

    What is the flange? All I know is the actual driver itself looks perfectly symmetrical, the edges of the magnet/shield are all even and such, I think the pole piece broke off of the bucking magnet and the actual driver magnet and jammed the coil, because I can see a little punch/hole in the pole piece through the bottom of the shield and it is WAYYYY off the to the side. If that's the case, then I got really unlucky here.
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  • F1nut
    F1nut Posts: 50,643
    I've got no idea how that shield is attached. Maybe reach out to Kim Jasper at Polk to find out.
    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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  • ChrisD06
    ChrisD06 Posts: 929
    F1nut wrote: »
    I've got no idea how that shield is attached. Maybe reach out to Kim Jasper at Polk to find out.

    I see a ton of glue on the bucking magnet, it could be adhered. I'll reach out to Kim whenever I decide to take a crack at it and find out (hopefully) for sure how it's attached. Would hate to destroy it any further considering the coil at least works and hopefully isn't deformed.
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  • xschop
    xschop Posts: 5,000
    edited July 2023
    I think the pics are in my phase-plug thread.
    Those flanges where the butyl surrounds attach are very weak and bend easy with the frame.
    Don't take experimental gene therapies from known eugenicists.
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  • ChrisD06
    ChrisD06 Posts: 929
    xschop wrote: »
    I think the pics are in my phase-plug thread.
    Those flanges where the butyl surrounds attach are very weak and bend easy with the frame.

    Oh you're referring to the spot the rubber surround attaches? No bends there, and it appear all symmetrical. It's definitely a shift INSIDE of the shield, which is super **** annoying, and mind boggling how that occured.
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  • xschop
    xschop Posts: 5,000
    Looks like some forensic dissection is in order.
    Don't take experimental gene therapies from known eugenicists.
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  • ChrisD06
    ChrisD06 Posts: 929
    More bad news: One of my CS400i woofers scratches at the top when I push it in evenly.

    I am inclined to believe this is a manufacturing defect however as I never actually tested for scratchiness on this woofer. It only occurs when the woofer is pushed all the way in I don't hear any problems.

    Fortunately I have some RT600i so I can just throw one of those in, but considering I'm getting a CS1000p I might not bother.

    HOWEVER I will note this woofer is super loose, like it pushes in and out way too easy compared to my other Polks. The other one is quite firm in comparison.

    I'm getting really worried now about magnet shift on these shielded woofers being possibly but I'll wait until I have one more problem (if ever) rather than panic now.
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  • ChrisD06
    ChrisD06 Posts: 929
    ChrisD06 wrote: »
    More bad news: One of my CS400i woofers scratches at the top when I push it in evenly.

    I am inclined to believe this is a manufacturing defect however as I never actually tested for scratchiness on this woofer. It only occurs when the woofer is pushed all the way in I don't hear any problems.

    Fortunately I have some RT600i so I can just throw one of those in, but considering I'm getting a CS1000p I might not bother.

    HOWEVER I will note this woofer is super loose, like it pushes in and out way too easy compared to my other Polks. The other one is quite firm in comparison.

    I'm getting really worried now about magnet shift on these shielded woofers being possibly but I'll wait until I have one more problem (if ever) rather than panic now.

    Nevermind, weird crusty white glue around the coil, it looks like gorilla glue. I bet you that this CS400i had spider separation for some reason and the old owner used Gorilla glue to glue it back. The coil doesn't move straight, the magnet is fine.
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  • ChrisD06
    ChrisD06 Posts: 929
    xschop wrote: »
    Looks like some forensic dissection is in order.

    I did some forensic dissection. It ain't good looking.

    Fortunately I've narrowed it down to being purely from impact, I highly doubt this type of shift would happen over time.

    acruj5o6g6d3.jpg

    The magnet shifted in the direction of the corner which took the impact. How bad is the shift?

    b32bsc058lrb.jpg

    It's bad. I cut the surround and went to yank the cone out and it held that coil really tight. You can see a piece of screwdriver which broke off from my trying to see if I could move the pole piece. It's stuck in that one spot. I don't know if my screwdriver is crap or the magnetic force is really that strong... but...

    7b50lq4zjgoc.jpg

    Here's the coil. It wasn't damaged when I pulled it out, infact it was perfect. I just wanted to unravel it for fun. Here you go.

    Lastly, I discovered a way to remove the dustcap perfectly. Make a slit in the center with a knife, stick your finger in, grab and pull straight up. It literally peels the whole cap off and the glue with it, leaving a clean looking cone. Would be good for cosmetics on Rob's phase plug mods.
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  • xschop
    xschop Posts: 5,000
    Wuhan coil time.
    Don't take experimental gene therapies from known eugenicists.
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  • Gardenstater
    Gardenstater Posts: 4,497
    Is that wire of round cross section or were the coils edge wound? Copper or CCA?
    George / NJ

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