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Radial Failure

Discussion in 'audio' started by Yank, Jan 4, 2022.

  1. Yank

    Yank Bulbous Also Tapered

    I've just replaced my second Harbeth woofer in three years, both from the same affliction - a cracked cone:

    [​IMG]

    Does anyone familiar with Harbeth know if this is the "usual" failure mode for these speakers?

    I was amused that it's a radial crack...



    Going by the rough condition of the screws, I would guess that the previous owner of these SHL5+ had replaced the woofer at least once before.
     
    Tom60300 likes this.
  2. Robert M

    Robert M pfm Member

    Very poor for such an extremely expensive brand.
     
    Peter Leo and Shane2468 like this.
  3. Yank

    Yank Bulbous Also Tapered

    Definitely not a Gallotone:

    [​IMG]
     
  4. Tryant

    Tryant pfm Member

    That's surprising. Did they offer any explanation and did they replace them for free?
     
  5. graystoke4

    graystoke4 pfm Member

    Hi, expensive brand ??, i always thought woofers were weaved carbon fibre ish, or paper weaved again, that looks like a cheeep plastic cone, never seen anything like that before, could be old thin plastic, gone brittle, keep away from that brand, :eek:
     
    Peter Leo likes this.
  6. Old Shatterhand

    Old Shatterhand pfm Member

    @graystoke4 It is expansive it is an injection molded cone. Because it is so stiff it can crack the same thing can happen with a ceramic woofer. I would stop talking BS if I haven't got a clue what I'm talking about.:rolleyes:

    @Yank As mentioned in STF: I have had 10 pairs of Harbeth speakers with the 8" driver even older ones from the mid 90th. and have never had a brockenone even if I played louder but if you push them too loud you hear the distortion and if you still push further...
     
  7. tuga

    tuga Legal Alien

    Wow!

    Has the cone material dried? What did Harbeth say was the cause?
     
  8. tuga

    tuga Legal Alien

    If I'm not mistaken, most woofer and mid-woofer cones are made of Polypropylene, a material which like Bextrene was firstly developed/used by the BBC Research Department, and used in the original Harbeth HL models I think:

    http://www.nutshellhifi.com/library/speaker-design2.html
     
  9. Mr Pig

    Mr Pig ^'- -'^

    Looks like a design or manufacturing flaw. They could buy the cones from anywhere. Change of supplier, bad batch, these things happen.

    I would definitely contact Harbeth and complain. A well worded letter can work wonders.
     
    Peter Leo likes this.
  10. tuga

    tuga Legal Alien

    The Radial material actually looks quite pliable (jump to time 15:43):

     
    graystoke4 likes this.
  11. tuga

    tuga Legal Alien

    The Radial patent is not clear in regard to the base material of the cone, it seems Shaw wanted to cover all the bases to avoid being "copied" or perhaps change the material at some point in the future:

    [​IMG]
     
    Peter Leo likes this.
  12. graystoke4

    graystoke4 pfm Member

    Tuga hi i agree, good video, he was bending the cone all over the place, and the size of the crossovers looked on the big size, by that i mean a lot of components, on each board,
    Old Shatterhand
    , i hope your not saying that a plastic woofer is comparable to a ceramic woofer, which to my understanding is a type of pot, which of course you cannot bend,
     
    Peter Leo likes this.
  13. Old Shatterhand

    Old Shatterhand pfm Member

    @graystoke4 I hope you don't say that every plastic has the same stiffness and can be bend.;)

    @tuga : The cone in the video is one of the P3ESR so much smaller and doesn't have to be that stiff (thick) because of the smaller diameter. Hard plastic can break easily if bend too much.

    @Mr Pig Another claim based on assumptions. Why should it be a construction and/or manufacturer fault? Do you have a degree related to injection mold or design of injection mold tools?
     
  14. Mr Pig

    Mr Pig ^'- -'^

    What do you think it is then? What would cause a cone to crack like that under normal use in a domestic environment?
     
  15. Old Shatterhand

    Old Shatterhand pfm Member

    I don't know it for certain but if I have to guess I would say deep bass at high volume. The OP said at SHF that he listens to rock and louder. IMO that isn't the right speaker for that use. Maybe a M40.x but even then I could thin of better alternatives like big Klipsch or Tannoy for example.
     
  16. Mr Pig

    Mr Pig ^'- -'^

    He did? Ok but I've never seen loud music cause a cone to split like that. It's a loudspeaker drive unit, playing music is what it's for. I've seen drivers damaged by abuse but I've never seen that happen.
     
    Peter Leo likes this.
  17. Old Shatterhand

    Old Shatterhand pfm Member

    https://forums.stevehoffman.tv/thre...-something-right.864210/page-64#post-28605578
    The same thing can happen to Ceramic drivers or even some metal drivers, softer polyproylene or paper can stretch more.
    It can be that there was a tiny air entrapment (sorry, I hope the term is right) that can have a negative influence, but you have to check that with a microscope. That was the reason I mentioned that assumptions or assaulting doesn't help, because without the right tools you won't find out.
    Yank mentioned that it isn't the first time that this happened to him. As mentioned before: "I have had 10 pairs of Harbeth speakers with the 8" driver even older ones from the mid 90th. and have never had a brockenone even if I played louder but if you push them too loud you hear the distortion and if you still push further..."
     
  18. chartz

    chartz If it’s broke fix it!

    Do you use them with your bass guitar? Marty?
     
  19. tuga

    tuga Legal Alien

    [​IMG]
     
  20. Yank

    Yank Bulbous Also Tapered


    I think there's only one source for their proprietary injection-molded cones. Harbeth buy them in very large batches, to lay in a supply that will last years. Or maybe there was just the one batch?

    I have not confronted Harbeth. I ordered a replacement woofer from the US importer before I had discovered the failure mode. I thought I would feel out the public first, to see if this is a known problem, before presenting Shaw & Co. with my information. For all I know this could be the standard result when Harbeth woofers are "blown"? Or maybe my cats did it? (there are paw prints on the grills)
     

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