speaker refoam

>"Applying tones to hear when it rubs works well."

I do that. I use a function generator on sine and set it to the free air resonance frequency It is easy to see, whatever frequency moves the cone the most. Then I see which way it might have to go to be in the most perfect center. It could be fine without touching it but I push it both ways on both axes to find which way the bent bends. Whichever way I got the most clearance before the voice coil rubs is the direction I "coax" it to before the glue dries.

Once I had to fix one someone else had done. He thought it would require removing the glue and tearing everything out. Nope. I simply bent the frame slightly. Of course this will not work on speakers with cast frames so just be more careful on those.

Actually there is money doing that. I heard of a guy in my state who started doing a few and still worked. In a couple of years he quit his day job to do this full time and makes decent bucks doing it. He can't keep up with the work. I am considering doing it. All you need is a little bit of exposure and a few satisfied customers. And of course I would have a discount for cash... It would tie in nicely with any of my stereo fixing endeavors as well, it would be practically the same customers. And audiophiles go in packs, at least on the internet. Of course some of them will fly cross country to hear another's system, but when your system cost more than a new car you do things like that.

 

On Tuesday, November 13, 2018 at 11:06:15 AM UTC-8, John-Del wrote:

This is a favor for a friend of a friend. I've never done a refoam before but I realize it's not rocket science but there's probably a learning curve. I won't have the option of do a trial run.

These drivers come out of a pair of Infinity Crescendos, and the plastic dust caps seem well bonded to the cone. I'd much prefer to shim the cone before bonding the foams, but I don't know if the dust caps can be removed somehow from the cones without damaging them.

Any advice appreciated.

I've done 6 refoams on Advent woofers and 2 on 6" JBL drivers. The first Advent kit came with shims and new dust caps. I followed the instructions and they worked fine. The next sets came without shims and I did not use any and everything is fine. I know the gap in the Advent drivers is quite large though I don't know if it's different in other brands. I have no idea what the gap is in the JBL but had no problem. As long as the spider hasn't shifted I don't think you'll have problems.

G²

 

>"As long as the spider hasn't shifted I don't think you'll have problems"

You can The voice coil could be ike:

|/|_|/| or |\|_|\|

with the top of the coil perfectly aligned but the bottom of it off due to the cone edges not being in the right position I use the generator and find which direction has the most leeway until it rubs and then "coax" it into the best position. This way when it gets pushed and expands thermally the clearances should not disappear.

 

[Look165]

I did refoam speakers (mainly woofers) 5 years ago for my mother and me
; they work pretty fine (8Ohms 45W and 100W peak).

The only specific check is the centering BEFORE glueing.
The best is to put a cylinder of paper or plastic (about 1 or 0,5mm)
around the bobin for centering (take care not to damage the wiring).
Then glue the foam ring to the cone and the circular skeleton of the
speaker ; NO FORCE TO APPLY ; let everything must rest where it is.
After 2 days, take the cylinder off, clean and glue the diaphram.

Then let rest for at least 2 days.

Goodhifi is a very nice supplier, when you provide the right
informations (manufacturer, exact type - written on the magnet...).
They also provide tutos for operations (see Youtube).
You can get new diaphragms, new cones and the appropriate glue.

Before that, check the wiring is OK ; no enammelled wire damaged.

Forgive my lack of English.

John-Del a Êcrit :

This is a favor for a friend of a friend. I've never done a refoam before but I realize it's not rocket science but there's probably a learning curve. I won't have the option of do a trial run.

These drivers come out of a pair of Infinity Crescendos, and the plastic dust caps seem well bonded to the cone. I'd much prefer to shim the cone before bonding the foams, but I don't know if the dust caps can be removed somehow from the cones without damaging them.

Any advice appreciated.

 

[Paul Hovnanian P.E.]

I've done a couple of them. As long as there is no need to repair or replace
the cone or detach it from the coil or spider (I think it's called), I
didn't have to shim the coil. The spider held it centered well enough that
as long as no lateral load was placed on the cone during the foam glue
setup, the air gap remained OK.

--
Paul Hovnanian mailtoaul@Hovnanian.com
------------------------------------------------------------------
A recent study found that women who carry a little extra weight
live longer than the men who mention it.