tweeters are the bane of existence

[fender3x]

I just spent the morning popping out three of my tweeters, finding good new elements for them, testing them, popping them back in and calking with dynaflex 230 latex caulk.

The problem was that at least two...and maybe three (could not be sure so I replaced it) of my tweets had rattles in them. I did not catch this when I tested them...all of them worked. I could not hear the rattle with the access panel off...only when the panel was in place. I guess there is more vibration in the chamber then--but what do I know.

It was only when I had the cab all sealed up, attached an amp and played bass on at the low end of the A and E strings that I heard it. At first I thought I had just not give the caulking enough time to dry...but the rattle was around the next day...so... I tore it open, and popped off the elements on the offending tweeters.

In two of the three cases, the cone/piezzo element had come detached from the plastic housing. This is something to watch for! There may be a fix for this, but at less than $1.50 each, I am opting to throw away offending elements.

Just tested the cab and no rattles. Won't play it loud, tho, until the new caulking dries.

I did find a way of ID'ing the offending tweeters without opening them: Hold the tweeter firmly in one hand, and tap the cone hard with an index finger. If the element is loose inside, you can hear a really faint rattle. I have now had this problem with 5 out of 14 tweeters that I used--all goldwoods from PE--so I'd say its common. At least in the 1005's I have been using. When I was looking for suitable replacements, I found one with a damaged cone (the inside part)...so that makes 6 bad ones to get 14 good ones. Moral? Buy more than you need!

Ok, end of rant.

Now a question... I wanted this cab absofriggenlutely sealed, so I sort of overdid it on the caulk. Is there a good way of getting it off the parts of the tweeters that show?

[Bill Fitzmaurice]

Did you read this? http://billfitzmaurice.com/phpBB2/viewtopic.php?t=1987

[fender3x]

Thanks! I have now!

I had read it months ago, but just quickly enough to determine that mine did not have the holes...Should have read more carefully.

In my case there is a little bit of a variation. I am not sure I am saying this right, but cone is still attached to the diaphram, but they are loose inside the back plastic housing. I did not know that would be problem, since they still seemed to work when I tested them. However, when I pumped some real noise into the cab with the access panel closed cab that the rattle began. I don't think I am having a problem with leaks...I am using the ported version anyway.

My first test once I got it all back together had no further noises rattles...If they appear, I will bite the bullet, pull it all apart and re-glue.

In any case, will do a careful inspection and glue up in any future builds.

[Bill Fitzmaurice]

cone is still attached to the diaphram, but they are loose inside the back plastic housing.

It's supposed to be that way. The cone edge is held in place only when the element is attached to the horn body.

[fender3x]

I am not sure what the problem was, in that case. I had a rattling tweeter before and you suggested swapping out the element. I tried it and it worked. It worked this time too, I think. If it was not because of the loose element...I am not sure why.

[fender3x]

My first test once I got it all back together had no further noises rattles...If they appear, I will bite the bullet, pull it all apart and re-glue.

They reappeared. To be sure I used the 30 Hz tone that Dave Perry suggested... It's defintely a leak, and definitely in a tweeter

What works best for sealing up the backs? I am guessing that airplane glue works the best for sealing the backs? I am a bit leery of Gorilla since it expands so much and since the bubbles seem to create the possibility of porousness. I also thought about using a bead of hotmelt around the joint just to make sure... This will be the third or fourth time that I have pulled these babies off and then re-caulked with latex... Will be repainting too, if I can just get this right.

[DAVID_L_PERRY]

They reappeared. To be sure I used the 30 Hz tone that Dave Perry suggested... It's defintely a leak, and definitely in a tweeter

What works best for sealing up the backs?

Hot melt the whole thing to death..........it will be a pain to remove a dead element, but not a major problem in the scheme of things. I probably doubled the weight of the whole assembly with the amount of hot melt I added, but I wanted to be sure about the leaks....It sure ain't pretty behind that piezo array...but who cares

[fender3x]

Hot melt the whole thing to death..........it will be a pain to remove a dead element, but not a major problem in the scheme of things.....It sure ain't pretty behind that piezo array...but who cares

This is how I'll do it then. There are lots of parts of my DR build that are not-pretty-where-you-can't-see. So the tweeters won't be lonely Thanks!

[DAVID_L_PERRY]

Thats why I like grills on the front of my DR's....

[fender3x]

Thats why I like grills on the front of my DR's....

Ha! I see the appeal now. My plan "b" is to put a grill just over the piezos, leaving the horn open. I may yet do that. I like the way the DR looks without grills, and it's easier to carry without a grill. But my calking skills are very poor...effective, but not aesthetic. Not having found an easy way of getting caulking off the tweeter housing, I have decided to remove the old ones, and use them for "melded array practice." I just ordered some more piezos, will mask them well this time and run the roller over the edges... Hopefully it'll look OK. If not, I may go with plan "b."

Does anyone use weatherstripping or neopreme speaker tape instead of calking? It would be less messy, but I am guessing it won't stand up to the pressure? (I was impressed by the pressure coming out of the ports when I played the 30 Hz tone...wow!)

[ripNdeb]

They reappeared. To be sure I used the 30 Hz tone that Dave Perry suggested... It's defintely a leak, and definitely in a tweeter

What works best for sealing up the backs?

Hot melt the whole thing to death..........it will be a pain to remove a dead element, but not a major problem in the scheme of things. I probably doubled the weight of the whole assembly with the amount of hot melt I added, but I wanted to be sure about the leaks....It sure ain't pretty behind that piezo array...but who cares

I was using layer after layer of ABS. I kept doing the flashlight test and still seeing minute leaks here and there. Then it dawned on me that if I put a coat of ABS right down the middle of the front seam, that might do it. I got a Que tip and laid down one layer of ABS down the center seam of the front and voila! No more leaks. After all, when the diffuser is in place, you can't see the ugly ABS coat anyway.

[LelandCrooks]

I use gasket doubled.

Generally a rattling tweeter is a bit of solder floating around inside. I shake them all pretty hard. Pull the head, shake out solder. Rattling from an unglued cone I've never heard. If your array is not sealed it could certainly be cab pressure on the cones.

Rubber cement liberally applied usually is a good cure around the driver lip. And below each screw there is a gap that must be sealed.

[LouC]

+1 on old fashioned rubber cement for sealing tweeter backs. Non toxic, easy to remove, done it a few times with excellent results.

As far as the seams on the piezo array, I wound up with lots of splinters and shavings. Added some to the backs and things tightened up. The ABS "dust" added to the glue can also stepped up the viscosity quite a bit.

Just a thought, I've seen heat shrink "saran wrap" in heavy gage for winter sealing windows. Wonder if something like that would work on the back of a piezo array?

Much as I liked the DR series, the OTOP12s I built really saved a lot of grief sealing everything, don't feel we lost much performance wise.

[Harley]

Just a thought, I've seen heat shrink "saran wrap" in heavy gage for winter sealing windows. Wonder if something like that would work on the back of a piezo array? .

My gut reaction is that it would get penetrated by any sharp bits of the piezo array ( wire, corners of tabs etc ) purely by the pulsing back and forth ( however minute it may be ) caused by the driver....too risky I feel.

[LelandCrooks]

Just a thought, I've seen heat shrink "saran wrap" in heavy gage for winter sealing windows. Wonder if something like that would work on the back of a piezo array?

Tried it a long time ago. Mixed results. A pita to install in the cab and keep sealed. The new DR renders it moot with the sealed chamber.