[avahifi]

Yes, the plasticlay coated woofer baskets were standard production with the Biro L/1 speakers.

Frank

[rcag_ils]

THANKS FRANK. I DID NOT KNOW THAT. I am not sure if it was even mentioned in the ad during it's production years. If it was mentioned, I missed it. That saves me a lot of work. Thanks again.

[murf]

This is from a speaker builder forum:

"I have been using Permagum on baskets for years. Specially stamped ones. The effect is measurable, specifically from 100Hz to about 800Hz. I don't put pounds. Enough to damp the tink-then-ring when you flick it to a dull thump is enough. Works for cast frames too. Just because a driver has a cast frame does not mean it is designed well and wont ring. "

"Adding mass to lower resonant frequency is not always a bad thing either. In general, a more flexible and non-hardening product will add more damping to the structure, whilst still adding the mass to lower the resonance freq."

"I have found stamped steel frames to ring a good bit, when out in open, but when screwed down into enclosure, most of the ringing vanishes.
I tried damping a few older frames, but was not sure if I really could tell a difference or not. The "rap on it" test sounded better, out of box, but not much different than the screw it down good into box with gasket sound.
Enclosure damping, much more so. "

"I use some of that peel and stick stuff, a generic version of Dynamat"

"I believe ... has been doing this in the full range discussion board for a while.... He used the press and stick window caulking rope. I think frost king makes it and calls it finger caulk. It is a non hardening clay. I have used it with good results."

"A very inexpensive alternative is to go to Lowes and pick up some "flashing."
Epoxy will work great. Try making a pencil out of epoxy and see how well it "rings" when struck.
They make putty epoxy which would really be easy to apply as well."

"I use Mortite as well...."


The concept seems fairly well accepted, but the product is debated!  FWIW, Frank probably spoke with Mr. Salk & some other speaker experts.

But:

"I've tried this on a couple of stamped midbass/midrange drivers using duct seal compound and it made no difference in measurements or subjectively once secured into place. YMMV though."

"This is where the rubber meets the ring, so-to-speak. If you can't measure the difference between raw and treated driver, you will not hear a difference, of that I have no doubt. This type of mod lends itself well to measurement. Mounting a driver on a baffle substantially reinforces it. I've made mods to driver frames that were very easily measured (cavity fill) and some (primarily damping) that made absolutely no measured difference. It's probably going to be more of an issue with large drivers IMO. All of my tests were not performed in boxes, they were on my 2mx2m test baffle, no box influence after mounting."

You pays yer money & makes yer choice.

Murf

[Mike B.]

I had a pair of Sequerra 2 + 2W speakers back in the 1980's. All the speakers were covered on the back with putty. The mid was a Phillips with it's own tube like enclosure. It was heavily coated as well. 

[heiba]

I remember the plasticlay mod in Audio Basics at the time. And in 1987 I bought a pair of B&W DM 330i. A great speaker that can be improved. I've tried different tweeters over the years, as the original tweeter was a bit hard sounding. For two years now I have used the Vifa XT25TG-30/04 tweeter and it works without mod to the crossover. Many years ago I changed the capacitors for Panasonic polypropylene that I bought from Frank. And later on I stuffed the box with polyester damping material in order to damp unwanted reconances. I did tune it by ear - too much and it didn't play low bass. I will try the plasticlay mod one day.

Ola
Norway

[Mark Korda]

Hi. I use Franks idea for my speaker mounting gaskets. This one is about 1/2 inch thick. I used a rolling pin and trimmed around the speakers frame with a credit card used as a knife. No vibes to the enclosure here....Mark Korda

[dB Cooper]

This is from a speaker builder forum:


"This is where the rubber meets the ring, so-to-speak. If you can't measure the difference between raw and treated driver, you will not hear a difference, of that I have no doubt. This type of mod lends itself well to measurement. Mounting a driver on a baffle substantially reinforces it. I've made mods to driver frames that were very easily measured (cavity fill) and some (primarily damping) that made absolutely no measured difference. It's probably going to be more of an issue with large drivers IMO. All of my tests were not performed in boxes, they were on my 2mx2m test baffle, no box influence after mounting."

You pays yer money & makes yer choice.

Murf

Unless you have the specialized equipment to make time-domain measurements, you will not 'measure' a difference- amplitude response is not affected unless you do something wrong, like use way too much material (affecting cabinet tuning) (possible with really small minimonitor cabs) or accidentally block a driver vent hole etc. IN my experience, speakers sound 'faster' because transient response is cleaner. Frank's suggestion in the original article to do one speaker and then compare to the other is a good idea. (Might want to use a mono recording or switch your system to mono for the comparison, so both speakers are playing the exact same signal- and pan with the balance control.) That will tell you whether your ears will find it worthwhile. I found it very worthwhile and have used it on speakers, TT's, even headphones (obviously scaling down the amount used).

[avahifi]

I have always recommended doing one speaker first and then compare them, side by side, with the system set to mono.  Have someone else run the balance control back and forth.  For best resullts, also have that someone scramble the speakers before you listen so you won't know which you are listening to.

Then, if you hear a useful difference, it won't be because of anticipation bias.

Frank