When should a LF driver be re-coned?

Printable View

November 15th, 2012, 12:14 PM
robertbartsch

When should a LF driver be re-coned?

I have a couple of 416s alnico Vs in storage. These are in good shape with no tears, etc and they work well. These have been purchased from others during the last 3 - 4 years, so I don't know where they have been for the first 30 - 40 years. My guess is they are circa early 1970s... (light green paint)

Should I consider re-conning these or should I just build VOTT boxes and play them till they are dead?

I've reconed similar drivers at GPA and they have turned out great.
November 15th, 2012, 02:12 PM
Altec Best

Re: When should a LF driver be re-coned?

They are 15" 416A's. If they play great just play them.You only recone when it is absolutely necessary.. Sagging Cone,Damaged cone,spider,etc... If you are storing them for a very longtime,3-4 years would qualify IMO.Flip them over every so often.. I had a pair that was damaged by leaving them face down for years...I bought them that way and when I measured them they measured very weak (Magnets).And probably why they were sold.When Bill finally figured what the issue was he said from storing them like that for so long the cone pulled the VC out of the gap and while he zapped them 3 times,they still measured very weak,the ( motors).. After recone they were back to factory spec...
November 15th, 2012, 02:29 PM
robertbartsch

Re: When should a LF driver be re-coned?

Quote:

Originally Posted by Altec Best

They are 15" 416A's. If they play great just play them.You only recone when it is absolutely necessary.. Sagging Cone,Damaged cone,spider,etc... If you are storing them for a very longtime,3-4 years would qualify IMO.Flip them over every so often.. I had a pair that was damaged by leaving them face down for years...I bought them that way and when I measured them they measured very weak (Magnets).And probably why they were sold.When Bill finally figured what the issue was he said from storing them like that for so long the cone pulled the VC out of the gap and while he zapped them 3 times,they still measured very weak,the ( motors).. After recone they were back to factory spec...

Yeh.... I remember that thread a while back. ...glad you finally got them working.... Bill at GPA is a great guy and very knowledgeable.

On another issue, I have a powered 18" sub-woofer (JBL) that is mounted in a cab and it is firing in a downward position. If I remember correctly, it has a foam surround. Anyway, I suppose this design is a future candidate for a sagging cone?
November 15th, 2012, 03:28 PM
Altec Best

Re: When should a LF driver be re-coned?

Quote:

Originally Posted by robertbartsch

Yeh.... I remember that thread a while back. ...glad you finally got them working.... Bill at GPA is a great guy and very knowledgeable.

On another issue, I have a powered 18" sub-woofer (JBL) that is mounted in a cab and it is firing in a downward position. If I remember correctly, it has a foam surround. Anyway, I suppose this design is a future candidate for a sagging cone?

I don't know the JBL brand as well.But from what I know they tend to need new foam surrounds every 10-15 years.. They may also have stiffer spiders and surrounds to deal with the effects of gravity,dunno on this one...Do you know what driver is in this Sub ?
November 15th, 2012, 04:02 PM
robertbartsch

Re: When should a LF driver be re-coned?

Quote:

Originally Posted by Altec Best

I don't know the JBL brand as well.But from what I know they tend to need new foam surrounds every 10-15 years.. They may also have stiffer spiders and surrounds to deal with the effects of gravity,dunno on this one...Do you know what driver is in this Sub ?

****

The driver is a JBL 2245 - 18" sub-woofer, I beleive. ...kicks butt...
November 15th, 2012, 04:38 PM
Altec Best

Re: When should a LF driver be re-coned?

Yup and recone kits for those if you can get them are Big Money $$$.I think they are like $300-$400. They last 10-15 years and then the foam surround dry rots.Give'r take a year or two.
November 15th, 2012, 04:55 PM
Old Guy

Re: When should a LF driver be re-coned?

I suspect the weight of the cone pulling down on the spider fatigues it, so the coil doesn't return to "zero".
November 15th, 2012, 07:42 PM
cradeldorf

Re: When should a LF driver be re-coned?

My cones are 58 Years old, And they sound excellent.
November 15th, 2012, 08:19 PM
Old Guy

Re: When should a LF driver be re-coned?

Quote:

Originally Posted by cradeldorf

My cones are 58 Years old, And they sound excellent.

As long as rotated occasionally, they can. But downward facing means the weight of the cone is constantly pulling on the spider. We've been referencing that.
November 16th, 2012, 12:39 AM
Alien_Shore

Re: When should a LF driver be re-coned?

Quote:

Originally Posted by Altec Best

You only recone when it is absolutely necessary.

+1

Bill @ GPA offers the same advice. When it comes to cones, if it ain't broke...
November 16th, 2012, 03:40 PM
Altec Best

Re: When should a LF driver be re-coned?

Quote:

Originally Posted by Old Guy

As long as rotated occasionally, they can. But downward facing means the weight of the cone is constantly pulling on the spider. We've been referencing that.

Exactly ! @ Cradledorf, And I was referring to the pair I bought off eBay that were in storage face down for 10 years on a shelf the seller said..And we were also referring to Robert's downward facing sub.Which ruined the spider (On Mine) and as OG said the VC didn't return to zero, in fact Bill said it was nowhere near being close to the gap and why they measured so bad.(Very Weak Motors).After the recone they measured back up to spec.

Woofers can last a very longtime mounted in cabinets,as long as they are rotated periodically it negates the effects of gravity.Once they are put on a shelf they should also be rotated periodically. (Upward & Downward) or (Facedown & Faceup).Mind you in a dust free environment.