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compression driver problem

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Jo bg View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jo bg Quote  Post ReplyReply Direct Link To This Post Topic: compression driver problem
    Posted: 16 December 2017 at 9:20am
Hi
i isolated the problem so here's a new specific topic
One of my 18sound nd1460 cds developed a hole in the response between 2 and 4k hz, here's a measurement without the horn.
what would you think could be the cause?
Misaligned diaphragm? burnt coil?
 
I am scared of removing the diaphragm to look at it as i have never aligned one but i think it's the only thing left to do...


Edited by Jo bg - 16 December 2017 at 9:21am
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Elliot Thompson View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 16 December 2017 at 10:32am

Have you considered sending the photo to Eighteen Sound? If it is a manufacture defect, Eighteen Sound should be able to rectify the problem.


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Elliot Thompson
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Jo bg View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jo bg Quote  Post ReplyReply Direct Link To This Post Posted: 16 December 2017 at 10:46am
hi
i've been using this rig a little more than once a month for the past 18 months, it's not new and i think this problem developed just now so i don't think it's a manufacturing problem.
 i felt i couldnt get the mid range right last session and i found out the reason was on cd was off 2 to 4k.
that mt121 took a hit, maybe it decentered the diaphragm?
i think later on we are going to remove it and check it out. hope i don't make it worse...
 


Edited by Jo bg - 16 December 2017 at 10:48am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jo bg Quote  Post ReplyReply Direct Link To This Post Posted: 16 December 2017 at 10:55am
uploads/20832/nd1460-1.doc
here's the transfer function, just rename to .trf
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Jo bg View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jo bg Quote  Post ReplyReply Direct Link To This Post Posted: 16 December 2017 at 11:21am
and here is a distortion measurement at 15 cm...
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Elliot Thompson View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 16 December 2017 at 11:41am

Unless you are willing to examine the voice coil for some means of damage, there is really nothing else you can do but send Eighteen Sound the photos. Sometimes it is best to let the manufacture handle the situation than, trying to play Mr. Fix It. Eighteen months is not long so, it should still be under warranty with Eighteen Sound.


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Elliot Thompson
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Jo bg View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jo bg Quote  Post ReplyReply Direct Link To This Post Posted: 16 December 2017 at 11:49am
hi
well one side of me wants to inspect this and learn how to deal with it and learn to replace a diaphragm when it's needed, at worse it should cost a new diaphragm.
 
the wise side says to see what 18sound says, but this means i will be in the same situation next time something goes bad and dependent from assistance...
 
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DMorison View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DMorison Quote  Post ReplyReply Direct Link To This Post Posted: 16 December 2017 at 1:28pm
Originally posted by Jo bg Jo bg wrote:

  
the wise side says to see what 18sound says, but this means i will be in the same situation next time something goes bad and dependent from assistance...
 

You won't lose out on anything by emailing them a couple of screengrabs and asking the question - you'll still have the drivers there and once you receive any info they send you, you'll be that bit better informed if you do decide to investigate further yourself.

Worst case, you're only waiting an extra day or 2 for them to respond, then you decide to carry on yourself anyway if what you get back from them leads you to believe that's appropriate.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote toastyghost Quote  Post ReplyReply Direct Link To This Post Posted: 16 December 2017 at 6:48pm
I don’t trust anything on that measurement frankly. Terrible coherency. I would wager something wrong with your measurement setup before suspecting a driver.
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