Refoaming Speakers

Back in the 1970s I purchased a pair of Advent-1 loudspeakers. They have served me admirably ever since.

The Advents were designed by Henry Kloss and are considered representative of what was called the East Coast Sound. They are large bookshelf or small floor speakers with a 10" woofer and a dome tweeter-- a two-way design. They sounded and still sound great. Here's a recent (2006) review from Stereophile.

The woofers are the large round components on the bottom. The paper cone is dark gray. The round center cardboard covers the voice coils. The foam rubber surround (outside the dark gray paper cone) is light gray. The surround is glued to the cardboard cones and the outside metal ring and keeps the cones from sagging.

By the mid-90s the foam rubber surround on the woofers of my Advents had begun to disintegrate. There were several quarter-sized holes, and every cautious touch of my finger to the surround created a new hole.

The foam supports the speaker cone; without it the cone will sag against the voice coil. The result is bad sound and, if not repaired quickly, damage to the woofer.I knew I had to repair or replace the woofers.

I was sure I could have located replacement woofers, but I was equally sure they would be expensive. And so I did some research on the fledgling internet and purchased a re-foaming kit from Orange County (the one in California) Speakers. It cost about thirty bucks.

When the kit arrived I removed the woofers from the cabinets and, following instructions, used an Exacto knife to clean all remaining foam and adhesive from the paper cones and the outside ring, and then attached them, using Elmer's glue.

By the next day the glue was dried. I put the woofers back in the cabinets and fired up my stereo. The Advents are still going strong.

Here's what a woofer looks like when the foam starts to go:

Here's a re-foam kit:

A couple of weeks ago I noticed the grille of my Optimus center channel  speaker was upside-down. When I removed it to flip it, I noticed both of the 5" woofers had holes in their surrounds. It was deja-vu all over again.

That's the Optimus, just above, with the grille off. 

My options seemed to be 1) buy a new speaker for a hundred dollars or more; or 2) spend thirty or so dollars on a re-foam kit.

But then there was eBay.

Yep, I bought new surrounds for $4.25 plus $2.99 shipping.

When they arrived I removed the woofers from the cabinet (that was a challenge, as the screws were hidden behind the rubber cups that hold the grille on, and it took me days to discover that). I spent an hour or more cleaning the cones and frames and then spent five minutes gluing in the new surrounds. They're drying now, and when I put the speaker together I expect it will sound great.

Alas, one of the binding posts (the place where you connect the speaker wire) on one of my ADS L-810 is loose. I'll have go to inside the box to resolder it.

Luckily, I'll never have to re-foam the woofers of my ADS'. The surrounds are made of butyl rubber, which doesn't deteriorate.

 By the way, the ADS L-810 is a superb speaker; easily and inexpensively maintained. They sound as good or better than most modern speakers that cost thousands of dollars. They look good, too. You can buy a pair used for about $300).

ADS L-810, One of the Best Speakers Ever

Don't even ask me about my Infinity Quantum 2s. I would never shut up.