The replacement foam surrounds from Rick Cobb (highly recommended) arrived last week. I've used Rick's foams many times, they are always a perfect fit. These are the correct filleted foams in the original black color. I bought my first set of foams from Rick as a kit, that includes a small bottle of glue and a 30Hz test tone CD. Now I just buy the foams directly from Rick. His prices are VERY affordable and his knowledge is unsurpassed. I use a bottle of Aleene's Fast Grab Tacky Glue that I picked up at a Local Michael's. With a $5 off coupon on any one item, it was practically free. I'd done about a dozen refoams with this bottle and probably have enough left for a dozen more. If you aren't doing your own refoaming, it's very affordable DIY project.
I got around to installing the replacement foam surrounds yesterday. Of course, removing the original foam and glue always takes more time and effort than installing the new foams. I'd already done this on the Boston Acoustics HD8 woofers, so I just had the Snell woofers to do. After getting them all cleaned up, I glued the foams to the cones yesterday morning before work. Using the original glue line as a guide, it was easy to center the new foams on the cones. I did all four in about 40 minutes. It takes a few minutes for the glue to get tacky enough to hold the foam in position and you have about 15 minutes to make adjustments before the glue sets up too much to easily move things around. I did them one at a time, starting with the HD8 woofers. It's probably not absolutely necessary, but I always allow the glue to cure for 8 hours before I move on to gluing the foams to the baskets. So, I let all four cure while I was at work and then glued the foams to the baskets last night after wok and let them cure overnight. Same procedure, with the addition of playing the 30Hz test tone while the glue was tacking up to make sure there was no voice coil rubbing. Again, about 10 minutes per woofer, 40 minutes total.
Here's some before and after photos (HD8 woofers on top, Snell Type KII woofers on bottom):
Although they were all made by Boston Acoustics (less than three and a half months apart), and all take the same replacement foam surrounds, they are not the same woofers. The HD8 woofers have the square(ish) frames, while the ones from the Snells are round. The Snell woofers also have a larger voice coil and larger, heavier magnets. Since the Snells were originally hand tuned at the factory, I wrote the serial numbers on the magnets with a black Sharpie so I'd be sure to reinstall the woofers back in the correct cabinets.
Tonight I will reinstall all four and begin my listening tests.
BTW, if you've never installed replacement foam surrounds, the square frame 8" Boston Acoustics woofers would be a good place to start. With the polypropylene cones, unlike paper cones, which are more delicate, there is almost no chance of damaging a cone when removing the old foam and glue residue. With the correct foams they practically align themselves. You'd have to really try to get them off center and have any voice coil rubbing. Just use the original glue line as a guide when gluing the replacement surround to the cone. Let the glue dry and then glue the foam to the basket. The square baskets have a recess that the foams just drop to into and fit perfectly. I still played the 30Hz test tone while the glue was tacking up, just to make sure there was no rubbing, but honestly, it wasn't really necessary in this case.
More to follow...
