[b5pt9]

I've got a rattle internal to one of my IB1's  .  I know this problem has come up before and some people have replaced midrange drivers.  I don't think this is my problem because the rattle is localized to the right side panel, centered vertically and toward the rear of the speaker.

I ruled out loose components on the crossovers by swapping them between speakers - the rattle is still in the right speaker.

What worries me is I can stop the rattle by lightly touching the right side panel  .  Even the slightest pressure will stop the resonance.  So I'm thinking either:

1) a wire is resting against the side panel (easy solution) or
2) internal bracing or other cabinet construction problem (massive problem)

I'll forward this to PMC in California on Monday, but any input here would be appreciated. 



 

[b5pt9]

Well I made some progress .  The photo is taken up inside the speaker cabinet, looking at the side panel about where the resonance seems to be centered.  The vertical piece that tees into the sidewall forms the shape of the transmission line inside the cabinet.

I can't tell if the sidewall is a laminate construction with hardwood sheet / plywood glued to outer MDF, or if it's one solid piece of 20mm thick hardwood.

The nature of the resonance makes the think the sidewall is laminated construction and the two pieces are vibrating against one another.  I might be able to put some woodscrews from the inside to solve this  .

Otherwise the resonance is occuring where the internal vertical piece meets the sidewall.  In this case I might be able to get small angle brackets up in there, or worst case it might need screws from the outside .

[mcullinan]

Are  they under warranty? If so maybe they would replace the speaker.
mIKE

[b5pt9]

Are  they under warranty? If so maybe they would replace the speaker.
mIKE

That would be wonderful but I'm not counting on warranty.  I'm cheap so I buy stuff used and take my chances  .  I wouldn't be surprised if this problem motivated the original owner to sell these.

[James Tanner]

Are  they under warranty? If so maybe they would replace the speaker.
mIKE

That would be wonderful but I'm not counting on warranty.  I'm cheap so I buy stuff used and take my chances  .  I wouldn't be surprised if this problem motivated the original owner to sell these.

Hi b5pt9

It is laminated - maybe try hot glue?

james

[b5pt9]

Hi James,

It's tough to get at that location in the photo.  I could peel the foam and run a glue bead down the vertical piece-to-sidewall contact, but I think the problem is de-lamination of the 2 large sheets making up the sidewall.

Some small woodscrews from the inside is the most practical method I can think of to pin the 2 pieces solidly together.

Do you happen to know the thickness of each sheet making up the sidewall?  It seems to be 20mm thick in total.

[James Tanner]

Hi,

Gee I do not know the thickness but Maurice or Andy at PMC will certainly know so you should hear shortly.

james
 

[b5pt9]

Thank you kindly  .  I'll wait to hear back.  These are #2381 and #2382.

[b5pt9]

James - sent you a PM.

[b5pt9]

Quick update in case anyone is wondering.  Andy from PMC has emailed and I have good confidence I can resolve this at home.  Will provide further info when I make some progress.

[jethro]

"I am wondering." Please keep us updated.