DIYHiFi.org

I was recovering the grilles on my beloved Snells and noticed that I could see through the woofers. I suddenly had a small clue as to where my bass had gone!

After searching around I found several outfits that sell replacement surrounds. The woofers are Vifa's and I was pretty concerned about getting an exact match. I couldn't find anyone that sold Vifa specific components so I convinced myself that the compliance of the surround was probably a second order effect compared to the air loading and decided to buy the closet fitting set that I could find.

It was a pretty easy thing to install the new surrounds. The only harrowing part was removing the old material from the cones. It had decomposed to a glue-like mess. I used a hobby knife as a plane to shave of the old gunk.

They are back in business and sound great. This is an easy fix if you have the same problem.

Driver after removing from the enclosure

New surround glued in place.

I found that I had to continually work the glue joint with my forefingers and thumbs to get it to seat properly.

Hi sabie22,

Nice job. D'ya mind if I send...

Those look like foam surrounds - all the Vifas I know have rubber surrounds. Are the boxes particle board? Reason I ask is the material exudes formaldahyde which eats foam (and our lungs). Always good to seal it off on the inside surfaces and cut edges.

Greg

"...so I convinced myself that the compliance of the surround was probably a second order effect ..."

Hahaha.... I like that. That's reality for you. Looks like it worked out great.

I wonder had you tried some heat, the old glue may have released better, and even, the new glue may have seated easier.

Next time maybe.

I noticed a cut in my foam the other day.... nice to see it can be done.

Cheers

When I did a pair a few years ago I hooked the driver up to an oscillator/amplifier.

After gluing the inner to the cone and letting that dry:

Fed a sinewave in at resonance to give 10mm displacement while running fingers around the outer frame glue line. Thie ensured that the cone was central and not scraping.

It worked a treat.

Hi Greg,

I'm pretty sure the originals were foam. It came apart in chunks and had a very spongy feel to it.

I think the boxes are some sort of composite. The baffle is, for sure. I didn't get a good look inside with all the stuffing.

I guess the formaldehyde must be a byproduct of urea glues or something? I
wasn't aware that particle board/MDF continued to release the stuff. I bought these in '90 so maybe its mostly gone.

best regards, Mike

Every exposed MDF surface must be filled with glue (the white wood glue).
It will last forever, even in humid places.

_________________
Carlos Filipe

"Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius - and a lot of courage - to move in the opposite direction." Albert Einstein

To center the voicecoil (if I remember correctly, it was awhile ago) we used to remove the dustcap and put 3 or 4 plastic shims between the voicecoil former and the center pole piece.

As to the cause of problem it could be gas from the cabinet but it could just be normal air (+ pollution) and the foam - I've seen a AR turntable mat that had turnrd from foam into very gooey glue, I saved the table but not the customers LP

Bill

Sunlight can break down some og the older ones too. They had little UV protection.