Drivers stored wrong for 15-20 years

[Skiivari]

Found a pair of drivers that were meant to be used in an old full range speaker kit and having found out the parameters they seem quite nice for a horn sub I've been dreaming of. http://www.seas.no/images/stories/prestige/pdfdatasheet/h1316_ca26re4x_datasheet.pdf

Anyway they're in really nice condition externally but storage in cold and humid conditions combined with apparently having had the cone pushed in during this storage has resulted in the spider being stuck in a position that isn't in the middle... They move nicely but the travel inwards is much shorter than outwards.
Is there anything I can do? I've been running them for a few hours with a 20hz sine wave on low level but it hasn't made a difference.

-Artturi

 

[freddi]

could you try weighting the cones from the rear with mortite (if it would stick?) and gently drive them with sine with the cones facing down?

 

[sofaspud]

An unusual situation, and I don't know how an expert would approach the problem. I'm thinking that low level 20Hz wouldn't be as helpful as just exercising the spider with a higher level music signal, maybe directing steam at the spider before that is done.

 

[revboden]

replace the spider and surround. Steam heating the spider may melt the glue or deform the cone.

 

[Ron E]

freddi's suggestion seems reasonable and worth a try before reconing them

 

[Moondog55]

Mount them in a baffle FACE DOWN and play bass for a couple of hours and see if it helps??

 

[Andrew Eckhardt]

A couple volts DC to push the cone in the opposite direction wont hurt the driver, but if you use the exact same corrective force it might take 20 years.

 

[NEO Dan]

Hair dryer and sine wave while inverted, but gently.

 

[dirkwright]

Did you ask the manufacturer?

 

[Skiivari]

First of all, got the link wrong, but they're 25F EW's even though it doesn't make a difference.

I've been driving them with sine and music at decent levels but the spider still returns to an offset location..
I just jammed one driver with a toilet paper roll (carefully) and I don't think it will help on its own but I might as well try giving it some heat. They are virtually unusable in their current state but I have nothing to lose.
I doubt SEAS will have any reconing kits or can help at all because this driver is listed in their "Very old vintage drivers"...

Will report back if I make any progress!

 

[Skiivari]

Can't seem to edit my post but the spiders are now straight!
All I did was blow some warm air form a hairdrier towards the spider while holding the cone in the opposite direction.
I hope this thread helps anyone with a similar problem, and thanks to everyone who pitched in.