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Electro Voice Sx 300 speaker

Bass driver giving off a noise like frying bacon of fairly constant level compared to varying audio level. They had used epoxy glue and soft contact glue at 2 different stages of fixing the spider to the frame. Epoxy had squeeged into the interior forming beads of solid epoxy up to about 10 mm long by about 2mm that had later broken off and was rattling inside. So gummy/soft glues only is the lesson . As there is always bits of sub-mm aluminium oxide etc , but greater than air filter mesh size , inside speakers, that don't seem to make any humanly observed rattling interference noises , anyone any idea what is the size that becomes intrusive ?. In the core that is , not staples etc on the outside. RoHS stickers all over and all sorts of other problems in the cab but not PbF isssues (this year)

Reply to
N_Cook
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You want to know the size of a particle that could cause a rub between the VC and the magnet structure core? Is so I can't imagine it would take much knowing the tolerances around the VC are measured in the tens of thousands of an inch. I've seen several of these type and guitar types get re coned living near an individual who did re-coning for a living. Some of the shims used while gluing especially in a studio monitor speaker like a Tannoy I saw get re-coned looked to be around 1.5 mil or slighlty more.

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Live Fast, Die Young and Leave a Pretty Corpse
Reply to
Meat Plow

These bits were rattling around in the interior space not passing through the air filter gauze or getting graunched in the vc gap. Demounted spicer and cone and for "reconing" this one I used 3 slivers of credit card, hardly thou/mil sorts of dimensions.

Reply to
N_Cook

I guess it's up to the person doing the re-coning as to what tolerances they prefer.

--
Live Fast, Die Young and Leave a Pretty Corpse
Reply to
Meat Plow

You need a jam fit, to coin a term. Not a clearance or sliding fit as you need the cone to stay at a pushed in distance, say 5mm below natural level. To allow the glue to have a closing pressure that is a once only application of force. Not removing hands and then placing a weight inside the cone. So the circular VC former goes slightly triangular with 3 credit card slivers or slightly squared with 4 (excessive deformation/ holding force for this one)

Reply to
N_Cook

The precision required for a shim cylinder (even with an axial gap) for coning/reconing would be near impossible to have a "jam fit"

This one given a work out with high power 50 hz and now back with the owner. Does not bode well with its fellow, 5 problems with this one. Loose horn, loose spade connector, another one the wire came out of the "crimp" on normal handling, spider of the bass unit partially unglued from basket and these bits of black epoxy rattling around inside (now in my black museum)

Reply to
N_Cook

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