avatar

zenmastering

Silverado

Posts: 155 Member Since: 21/02/2011

Lead

Jul 6 15 4:24 PM

Tags : :

Hi There,

I have a pair of Norberg BCS16B that need new foam surrounds for the woofers.  Information about these monitors is scarce and this is the place where I thought I might get some valid info.

Are foam surronds available?

What about  'new' woofers?

Any assistance greatly appreciated!

Graemme

Graemme Brown **Zen Mastering** Gabriola, Canada 1.604.874.9096 info AT zenmastering DOT net

Quote    Reply   
avatar

ssltech

Aqua Marine

Posts: 4,050 Member Since:22/01/2011

#2 [url]

Jul 7 15 8:18 AM

Foam surrounds for pretty much everything are available at very reasonable prices at Orange County Speaker... www.speakerrepair.com
I'd be inclined to try that first... and if you can't get replacement woofers, it may be the route you have to go anyway.

Quote    Reply   
avatar

strummer

Gold Finger

Posts: 355 Member Since:05/02/2011

#5 [url]

Jul 7 15 5:52 PM

I can second Keith's recommendation of Orange County Speakers. They've done surround replacements for me twice. Their customer service and quality of work were excellent.

Last Edited By: strummer Jul 7 15 5:54 PM. Edited 1 time.

Quote    Reply   
avatar

soapfoot

Ruby Baby

Posts: 7,310 Member Since:04/02/2011

#6 [url]

Jul 8 15 5:12 PM

I'll dissent from Keith slightly (and it's with much trepidation that I do so)--

In my experience, the BEST foam for surrounds right now is available from a seller named Rick Cobb. On eBay he goes by "looneytunes".

My experience primarily lies with old JBLs-- I've refoamed a total of 6 old JBLs of various sizes, and did one pair with the stuff you get from the more mainstream suppliers, and the other four drivers with Rick Cobb's surrounds. Cobb's are far and away more like the original foam (what came on JBLs, at least) in both look and compliance. I believe that they allow the speakers to perform most like they did from the factory.

At the very least, I would do some research and look around.

Best of luck!

brad allen williams

Quote    Reply   
avatar

soapfoot

Ruby Baby

Posts: 7,310 Member Since:04/02/2011

#8 [url]

Jul 9 15 8:51 AM

I know! It's foolhardy to disagree with Keith on any technical matter! And it's also a risky proposition to do a DIY re-surround job the first time. But my very first go-round was better than a pair I had professionally re-done by an authorized JBL service center (though JBL does NOT sell factory re-surround kits, and does not recommend re-surrounding... they recommend a full re-cone instead).

I like to use a 30 cycle tone to keep the voice coil centered in the gap while the glue dries. I have a few tricks...

I remove as much of the old surround as I can through mechanical means. A lot of times it will just crumble off. Usually there's still a fair bit of residue left on the back of the cone (or front, if the surround attaches to the front of the cone). I like to use a AAA battery with alligator clips to lift the cone just enough to allow me better access to the back side. I disconnect it periodically (when not directly needing to access some bit) so as to avoid letting heat build up in the voice coil (just a precaution).

I've found that isopropyl alcohol on a cotton swab is very good at dissolving and removing this residue, at least on JBLs. Obviously you do NOT want to get the cone wet-- it's an exercise in care. But with patience, you can get the cone cleaned to a perfectly clear, flat surface. I like to inspect with a pen light before proceeding.

Apply the surround to the cone using the appropriate adhesive , smooth out ANY gaps or wrinkles. Again, the AAA battery and pen light comes in handy. Then I like to allow this to dry and set completely. Once it sets up, I run a bead of adhesive around the cone right at the roll to form a good seal.

Finally, apply adhesive to the frame and affix the other edge of the surround... again, NO GAPS, NO WRINKLES. Then apply the 30 Hz tone at modest level to center everything, and keep it centered while drying. Listen for voice coil rubs (scraping sounds) and if you hear any, stop the tone and adjust-- you've got something badly off-center. I check them periodically as they dry to make sure the vibrating of the tone doesn't cause them to come unstuck. Sometimes I add some light clamping-- little soft clips around the circumference.

Once it's good and dry, I apply the gasket parts over that.

My track record is perfect (knock wood!) so far.

brad allen williams

Quote    Reply   
avatar

ssltech

Aqua Marine

Posts: 4,050 Member Since:22/01/2011

#9 [url]

Jul 10 15 1:30 PM

I'm going to defer to Brad so far as preferences go for people to work on specific drivers... With no reservations at all. I'm glad to learn of endorsements for people who do good work.

For myself, I've always had refoam DIY jobs go flawlessly... It's really just a zen blend of patience, curiosity, and focus. -A different person -one who thinks along the lines of "well, since I'm waiting for this to set up, I may as well answer a few emails, oh, and I can get that car waxed while the sun is in the shade... Oh, and I can give the dog its worming pill..." should probably NEVER attempt a refoam/recone or any one of several other jobs. -My wife for example, I don't even trust to boil pasta, since if she doesn't feel that something is challenging her every single second, then she feels like something else should be occupying her attention. She could never wax a car. Heck, she can't cook macaroni without making a single agglomerated mass of pasta that you can pick out of the pan with a fork! -She is definitely NOT speaker-fettler material.

Quote    Reply   
avatar

zenmastering

Silverado

Posts: 155 Member Since:21/02/2011

#10 [url]

Aug 1 15 8:14 PM

Just to report back:

I ordered new surround kits from Rick Cobb (Thanks Brad!), who has an eBay store under the name of "looneytunes 2001". His price was better than the others and delivery was a mere five days to the West coast of Canada. Rick's cone 'centering' procedure is what Brad described above; use a 30Hz tone to energize the cone/coil and it will 'auto-center' in the magnet gap. This is much easier than removing the dust cap (at least on these speakers) and it worked very well.

The following is the kit that Rick recommended for woofers like those used in the Norberg BCS-16B:

http://www.ebay.com/itm/BEST-Speaker-Foam-Surround-Repair-kit-Infinity-6-6-5-Reference-One-RS2000-RS10-/171833796777?pt=LH_DefaultDomain_0&hash=item280217a8a9

Foam surround dimensions - p/n #610-145 / Infinity 6/6.5"
Inside diameter (I.D. edge to edge): 4-3/8"
Outside diameter (O.D. edge to edge): 6.0"
Inside (inner) attachment lip size: 5/32" (angle attachment lip)
Outside attachment lip size : 3/16"
Roll size: 3/8"
Cone diameter: 4.75"

What I learned: It's easy to use too much glue. I imagine by the time I've done about a gazillion of these, my technique will be solid ;->
All in all it was easy and just required a little patience and concentration.

Thanks for all the help here!

Graemme

Quote    Reply   
Add Reply

Quick Reply

bbcode help