I thought I read that *adding* insulation was the correct approach, not removing. Seems there have been many discussions that adding fill, for some reason, makes the cabinet larger in volume "mechanically". Not physically of course. I've never seen this adequately explained, but there are people who have confirmed this, but again most of those were subjective and not objective, that I recall.
The correct approach varies depending on a lot of variables. If the original design engineer designed the damping that way then there may be a good reason for the placement of the fiber. Adding insulation is usually worth a try with a sealed system. But on a ported speaker like these it gets complicated. Port size and placement and controlling reflections gets very complicated.
I wouldn't make any changes that couldn't be un-done.
Agreed. What I did can all be undone in a matter of moments.
I'm confused:scratch2:. Since if been here all I've ever heard is people bash 'Sui speakers.:thumbsdn: But now people like them?
We humans are a weird bunch. BTW, I own a pair of 1500's and like them. I must be kookoo:screwy:
Oh, everyone bashes pretty much everything if you wait long enough. I was bashed since the 70's for being keen on Radio Shack's offerings, laughed at and dismissed. Now the Mach 1 has a huge following and they sell off CL before noon. If you wait long enough, it'll all come back in to fashion.
Dampening material in vented speakers usually is used to control the midbass/lower mirange reflections from bouncing back to the woofer cone. Even more important with mild 6db or 12db crossover slopes.
The problem in a vented enclosure is that it really doesn't increase the volume the woofer see's much (unlike a stuffed sealed box)-but the space it occupies can change the port/box tuning, and also (with some woofers in particuliar) how it "breath's in the enclosure" and it's transient response.
The most beneficial way to to have the dampening material directly behind the woofer.
Sometimes it is used to smooth a impedance peak, especially if the woofer was designed for a larger box.
Sometimes they design the ported enclosure as a leaky sealed box-and stuff it full (ESS).
If the woofer suspension is overly stiff from age, this could explain the improvement.
You could easily measure the internal volume, plug in the port size and length and figure out the box tuning.
The minimal amount of damping required to control reflections would be ideal.
If it's for impedance control, you may have to leave it-on the other hand if the suspension isn't up to what it should be-maybe leave it out till you can repair it.
I would highly doubt they used it to (fine) tune the box-as that's a poor way to use damping in a ported enclosure.
I just read through your words, hit a few snags. But I'll figure it out. Thank you so much for stopping by and offering up the information, it's much appreciated!
I gently pushed in on the woofer in the enclosure that I modified, it didn't seem oddly stiff to me. But I don't have a "new" one to measure against, so I don't really know. At the moment I'm hesitant to use a solvent of any type at the moment to loosen things up. I would need to do more reading, maybe some guidance before I move in that direction. But from what I've read on the net, it could very well help things greatly by loosening it up.
Biggles
