123A modification-- improvement or not?

[mbottz]

Has anyone ever taken an L-100 123A Woofer with a damaged surround and installed a replacement foam surround? If so I would be interested in some feedback on the outcome. Was it beneficial or a waste of time.

Also is there a replacement accordion style surround like the original which can be installed to replace a damaged woofer surround?

Thanks

Mike

[Robh3606]

How bad is the tear?? I have repaired them using a piece from a trashed cone. I heated it up with a hair dryer so it got nice and sticky and and the resin bonded the patch in place.

Rob:)

[mbottz]

This one has a large piece missing on one side and several tears on the other side. I dont think it can keep the cone centered any longer as it rubs when played.

[Earl K]

Also is there a replacement accordion style surround like the original which can be installed to replace a damaged woofer surround?

Hi,

- A good experienced reconer should be able to install a high compliance "aftermarket" accordian style surround.
- I had this done 15 years ago on an ancient 12" that needed help.
- I believe the parts used were originally meant for an Altec 414 .
- A creative reconer can easily rebuild a surround .

- If you want to do it yourself with a foam type , then contact someone like
Rick Cobb at mailto:[email protected] ([email protected]).
- Many people here have used his products and enjoyed his professional advice .

:)

[GordonW]

I've done surround replacements on 123A and 2213H woofers, both in the store (where I work), and for people on the board here. It's a dimensional equivalent, of equivalent stiffness, and I use an "Altec-type" surround coating compound ("rubbery", slightly sticky even after drying) on it. Measurements show that it matches the originals very closely... it's pretty much impossible to reliably measure a difference, or to hear any difference.

The nice thing, is that these surrounds are available to most any good reconing shop. Just be sure, that they use one of the CORRECT stiffness... it's easy to get one that's TOO stiff (which will make the bass response even a bit more "midbass heavy", at the expense of low bass, than stock)...

As for foam- there's no fundamental reason why that shouldn't work, on a most basic level. It might actually improve the excursion-vs.-distortion characteristics of the driver a bit. Don't know what it'll do to the midrange response, though... the additional damping of the foam, might cause a midrange "dip", in the system, due to a lessening of the high-midrange output of the woofer...

Regards,
Gordon.

[DavidF]

...I use an "Altec-type" surround coating compound ("rubbery", slightly sticky even after drying) on it...

Gordon, are you able to identify a brand or source of the coating?

DavidF

[pelly3s]

I have a can of Altec doping compound which is Tolune Hexane based, and I have some from Electrovoice which doesnt get sticky but I like it a lot better. It is easier to work with and stays extremely flexable

[DavidF]

..Tolune Hexane

Thanks for the advice. The above sounds like a character out of a Frank Herbert story.

DavidF

[duaneage]

I would be careful with a foam edge that the woofer does not excurse too far. The xmax of the driver must be respected.