Sound deadening of driver frames?

[lunchmoney]

I've seen that some people are applying rope caulking or some other form of dampening to the steel frames of drivers...

I'm wondering if I should do this to my Dayton 5.25" classics before installing them... I've got some leftover Damplifier Pro from my car audio stuff (similar to Dynamat).

Is this worth doing? Or placebo effect?

[philiparcario]

larger drivers would benefit more. chances are you are not going the have a lot of vibration problems with those drivers.

[denton]

I have no experience that says this will help, but I am unaware of any reason NOT to do it. Those people who have claimed audible improvement, at least in my experience, were applying damping to stamped frames on large drivers.

[terryo]

I'm probably going to get boo'd, but I have one foot in the "fullrange" camp, so I'm pretty familiar with most of the driver mods. My "Hi-Tweek Black Box" speaker uses the lowly Radio Shack 1197 4 inch driver ("Blue Box"). The goal of the design was as a nearfield Monitor for a very small room. The thing about some of the "Cheaper", that is, inexpensive drivers is that they often use stamped frames that may be somewhat thin and are reputed to ring. Another factor, and it may be a problem is the junction between the Magnet and basket. Some aren't glued very well, so it pays to take care of that problem as long as you're tending to various "mods".

First, I mix up a small batch of epoxy and apply it to the junction of the basket and magnet as a preliminary wet coat. Taking the remainder of the epoxy, I mix in Pulverized Lime to create a thick dough which is forced into the groove between the Magnet and basket. I sculpted it to a nice smooth surface and let it set up. BTW, I use a finely powdered Lime, it's like sifted flour and is often sold as Marking Lime (for marking Ballfield base lines, etc.).

Second, I take felt strips cut to the size of the legs and glue it with Aleene's Original Tacky Glue to the inside of the Basket legs. Use clothes pins to hold it in place until it sets. Aleene's is a soft glue and has a certain amount of give, which may or may not dampen the legs a bit. The felt is used to help mitigate reflections back through the cone.

Third, you have a choice of using Duct Seal or oil-based modeling clay. Both remain pliable, never harden and stick well. I used oil-based modeling clay for years and it works well, but I've come to think Duct Seal may be "slightly easier" to use and I think it may be superior for damping.
Anyhow, select which you're going to use and roll it out with your Wife's best rolling pin into a thin sheet of whatever thickness you need. Cut out with a sharp knife strips the width of the basket "legs" and then apply it, pressing it into place securely on the leg. Repeat until all legs are covered. The Clay or Duct seal can extend onto the epoxy/lime junction.

Forth, I make a "felt cap" to fit over the magnet structure and down the sides using what my wife terms as "Darts" to allow the transition from across the top to where it goes down the sides of the magnet. Once you have cut it out to the general shape, then apply a nice healthy coat of Aleene's to the area that the cap will occupy and then place the cap into place and press it into place gently to insure that the Aleene's adheres to the felt and it's centered on the top of the magnet. The sides are then pressed into place and the whole cap is held in place with an audiophile approved rubberband around the magnet's circumference until it sets up.

BTW: Dave Dlugos of Planet 10, liked this idea so well he tried it out and placed the impedance measurements of the before and after "felting" on the pages of diyAudio. Hint: it helped a bit, nothing extravagant, but it was discernible.
I hope this is of some help.

Best Regards,
TerryO

[Æ]

Good idea, never hurts to "dampen" any vibrating metal.
I've done it before, it helps/works.
Try some DYNAMAT type of peel and stick material.
Parts Express sells some of their own peel and stick, 268-030 very affordable. Easy to cut with utility knife or scissors.

[gmilitano]

Like Terry, I have used duct seal. It works well and is inexpensive.

[edlafontaine]

lunchmoney, your question is timely. I have a pair of Pioneer B20's that I will treat with much of what we see here.

Terry offers a good overview.

Let me offer a caution: Here in KY some people went into a store and asked for "lime". They used what they received to mark the lines on the football field for that weekend's game. As the game progressed, it began to rain. Players began to complain about itching, then burning from contact with the field. The material used to mark the field was hydrated lime. It becomes caustic in combination with water. Many players went to the hospital, some with second degree burns.

Your farm store likely keeps a stock of agricultural lime (ag lime). That's the mild-mannered kind. It is dry, pulverized limestone.;)

Stay away from the hydrated stuff unless you use proper protective gear.

[terryo]

lunchmoney, your question is timely. I have a pair of Pioneer B20's that I will treat with much of what we see here.

Terry offers a good overview.

Let me offer a caution: Here in KY some people went into a store and asked for "lime". They used what they received to mark the lines on the football field for that weekend's game. As the game progressed, it began to rain. Players began to complain about itching, then burning from contact with the field. The material used to mark the field was hydrated lime. It becomes caustic in combination with water. Many players went to the hospital, some with second degree burns.

Your farm store likely keeps a stock of agricultural lime (ag lime). That's the mild-mannered kind. It is dry, pulverized limestone.;)

Stay away from the hydrated stuff unless you use proper protective gear.

Ed,
Good point, and as a matter of fact, I picked it up at the local Grange. I believe it was $3 or $4 for 50 lbs., although this was a few years ago.
It's also good for Greening your lawn I believe:)

Best Regards,
TerryO

[johnastockman]

I've seen that some people are applying rope caulking or some other form of dampening to the steel frames of drivers...

I'm wondering if I should do this to my Dayton 5.25" classics before installing them... I've got some leftover Damplifier Pro from my car audio stuff (similar to Dynamat).

Is this worth doing? Or placebo effect?


I've done this since I first found this forum and Dave Brown's web-site. I saw rope caulk used on the Dayton 6.5" woofers for the dB616. I've used the rope caulk, but since I found Cascade Audio's different products, I use those now, mostly the VB-1. My nephew used some of their peel 'n stick products and spray-on for his car and there was a noticeable improvement over the dynamat that he took out. Just wasn't getting the job done like the Cascade. A combo of the VB-1 and damping sheets made a big difference. The comparison demo between other brands and Cascade's that we had set up at CES was very convincing (both sheet and spray-on material). I've used the sheet and VB-1 on driver frames, both the polymer/plastic and stamped steel frames. I can hear a difference, mostly upper bass and midrange, but I have no measured evidence to back me up.


John A.

[jonpike]

Yeah, I'd say tap on various things, and if there's significant ringing, it might be worth a treatment. Some plastic body tweeters can do this more than you might expect.

Another thing to use in the putty catagory, is some stuff called "Quake Hold". Generically, its a "museum putty"... something used to tack items down securely on a table or display.

It's pretty sticky, but non-staining, leaves NO residue. Probably silicone based. It's fairly massy for its volume.

I like it for cone weight, when doing delta mass VAS measurments. I've used it on a few drivers, to dampen out possible vibrations.

[brianp]

Let me offer a caution: Here in KY some people went into a store and asked for "lime". They used what they received to mark the lines on the football field for that weekend's game. As the game progressed, it began to rain. Players began to complain about itching, then burning from contact with the field. The material used to mark the field was hydrated lime. It becomes caustic in combination with water. Many players went to the hospital, some with second degree burns.

Your farm store likely keeps a stock of agricultural lime (ag lime). That's the mild-mannered kind. It is dry, pulverized limestone.;)

Stay away from the hydrated stuff unless you use proper protective gear.

Yep. Hydrated lime is calcium hydroxide, a strong base and rather caustic. Not nearly as bad as quicklime, which is calcium oxide and reacts violently with water to form the hydroxide. Ag lime is calcium carbonate, and is quite benign.