Fabulous Free Factory-Authorized Tweak!

Brian Cheney · « **on:** 12 May 2004, 09:53 pm »

Some years ago John Bau coated the paper cones of his TC50 with Elmer's glue to stiffen them.

Unfortunately it also rendered the diaphragms noiser, negating any benefit. However, since the noise is mostly high frequency I always wondered whether Elmer's (yellow carpenter's) would stiffen woofer cones to good effect.

Since our Passive Radiators are very low mass (less than 20g) paper cones I decided to paint them (both sides) with Elmer's, let them dry, and reinstall (being careful not to let glue drip onto the spider).

The results are most efficacious. In other words, try it and be amazed. You may or may not want to remove a little putty from the PR to compensate for the residual mass of the glue solids.

If you don't care to take out the PR just paint the side of the cone facing you. You will have to unscrew the base to access the PR. Works well with all floorstanders and subwoofers we make.

Enjoy!!

nathanm · « **Reply #1 on:** 12 May 2004, 10:04 pm »

Can we add dried macaroni or glitter?

brj · « **Reply #2 on:** 12 May 2004, 10:41 pm »

Have you compared Elmer's glue with other coating (doping) materials? I saw some discussion about using C37 lacquer as a coating in another AC thread, and am wondering what is driving the improvement in sound.

Since increased driver stiffness is the primary benefit, that would seem to indicate pursuing whatever coating material gives you the most stiffness for the least added mass. (Any theories about carbon atoms shifting resonant frequencies aside.)

Thanks!

Brian Cheney · « **Reply #3 on:** 12 May 2004, 11:19 pm »

I like the glitter and macaroni idea.

Be careful to not drip glue on the foam surround. If you do, wipe it off immediately with a very damp cloth.

Elmer's is the stiffness-to-weight champion for paper cone drivers.

ekovalsky · « **Reply #4 on:** 13 May 2004, 12:44 am »

What are the differences we should expect to hear?

Tighter bass, deeper bass, less distortion?

Worth doing to the 12" passive in the RM/X ???

DFaulds · « **Reply #5 on:** 13 May 2004, 01:56 am »

Brian, if this "tweak" worked so well perhaps you should consider using a PR with a kevlar impregnated paper cone. More costly, but it makes for an incredibly stiff cone which is probably why it is very popular in some of the better commercial and DIY subs.

Brian Cheney · « **Reply #6 on:** 13 May 2004, 02:00 am »

I already have very low mass paper cones custom made now (by RDM)and have not found a stiffer cone that was not too massive (15g for a 10"). But I'll check out paper/fiberglass.

Owners who do the Elmer's paint job should post their impressions.

pjchappy · « **Reply #7 on:** 13 May 2004, 02:01 am »

Brian, not worrying about price, would there be any benefits to using a CF PR?

Thanks!

p

Brian Cheney · « **Reply #8 on:** 13 May 2004, 02:01 am »

Eric: By all means do the Elmer's paintjob on the RM/X PR cones, inside and out. Big rewards for no cost.

zybar · « **Reply #9 on:** 13 May 2004, 03:49 am »

Man, that's a lot of PR's for me to do...

(2) RM 40's + (2) Larger Subs

Time to get up to Depot.

George

zybar · « **Reply #10 on:** 13 May 2004, 03:51 am »

How thin or thick should the glue be?

I am guessing a very thin coat?

George

Brian Cheney · « **Reply #11 on:** 13 May 2004, 04:33 am »

A thin coat is fine, apply with a 2" brush and don't allow drips or puddles to accumulate. Allow to dry 6 hrs before playing. Lots of fun, big rewards.

Keep the glue away from the foam surrounds.

ekovalsky · « **Reply #12 on:** 13 May 2004, 05:54 am »

Quote from: Brian Cheney

Eric: By all means do the Elmer's paintjob on the RM/X PR cones, inside and out. Big rewards for no cost.

Will pick up some glue and a brush tomorrow and report back. Thanks for the tip!

zybar · « **Reply #13 on:** 13 May 2004, 12:35 pm »

Eric,

I will wait to hear from you before I take apart anything.

Are you going to do both sides or leave the PR in place and do the single side?

George

koteng · « **Reply #14 on:** 13 May 2004, 01:49 pm »

The glue mentioned here is it the Elmer's Glue-All glue? White bottle with blue and orange markings?

Does it have to be Elmer's glue? I don't think it is availible outside the US.

I live in Norway.

Regards
Roger

meilankev · « **Reply #15 on:** 13 May 2004, 03:08 pm »

Roger,

Welcome to Audio Circle !!!!

Wow, I didn't know VMPS speakers were so well-travelled. I'm sorry - I can't help you with your question. I just wanted to welcome you to our little area.

Kevin

ekovalsky · « **Reply #16 on:** 13 May 2004, 05:10 pm »

Quote from: koteng

The glue mentioned here is it the Elmer's Glue-All glue? White bottle with blue and orange markings?

Does it have to be Elmer's glue? I don't think it is availible outside the US.

I live in Norway.

Regards
Roger

In the original post Big B said yellow carpenter's glue. So probably this is the wood glue, not the ubiquitous "Elmer's Glue-All". I think this is the product he refers to:

http://www.elmers.com/product/product_page.asp?pCode=E700

Big B will you confirm?

Wood glue does make sense since this is a paper woofer and paper is obviously a derivative of wood.

I'll head to HD later and pick some up along with a 2" paintbrush. Most of the job for me will be moving the RM/X to the ground and then particularly back upright (about the only time I wear the old hernia belt

) so I'll probably remove the passive drivers completely and paint them on both sides like Big B did.

maxwalrath · « **Reply #17 on:** 13 May 2004, 05:15 pm »

Damn, Brian...you have to wait for a week AFTER I sell my VMPS's to introduce this cheap tweak?

Brian Cheney · « **Reply #18 on:** 13 May 2004, 05:28 pm »

The yellow carpenter's glue is the stuff you want.

You're right, this is the wrong time for a cheap tweak like the Elmer's paintjob. Forget I said anything.

maxwalrath · « **Reply #19 on:** 13 May 2004, 05:36 pm »

sorry to vent...I miss them.