Proper surrounds for JBL woofers

[bigyank]

I just received my new surrounds for my L46 project. Got the first speaker all cleaned up and that is when I noticed the surrounds (old) are black and the new ones are gray. Contacted another member here who sells some and these are gray as well.

If gray is all I can get (current ones fit awesome!!!), can the surround take staining or will this screw up the characteristics of the surround.

Yank

[Zilch]

I wouldn't mess. Let them be gray....

[John]

Why!!!:banghead:

Did you ever think the old ones started out life as grey and then got dirty and turned black??;)

[bigyank]

Here they are side by side. Note the gray surrounds are not glued yet. I put them together to see how the fit is.

Yank

[mech986]

Hi Bigyank,

From some research I did with the L46, the original surrounds were a very thin rubber that was black, very unusual compared to any previous surround material that JBL used, pro or consumer - mostly pleated cloth or paper (treated with the sticky goo sometimes), or single or double roll polyurethane foam of the time (80's-90's). AFAIK, the original surrounds were never available from JBL consistent with their not recommending refoaming/resurrounding.

In my discussions with a number of JBL service folks, the L46 must be refoamed with a standard foam surround (now a more stable polyether type) which for the most part are only available in a grey color. Some foams are shaped better for the cone profile and that would likely be the most important issue regarding fit. There are some differences in foams due to their thickness and springiness so getting them from a place that has had experience with the L46 driver or JBL stuff in total would be reassuring.

I have not seen any foam surrounds done in black in general. However, I have seen some in blue and Red (usually for Cerwin Vega).

Regards,

Bart

[bigyank]

Thanks! I finished cleaning off #2 and yes, the surround was more rubber then foam and was a pain in the a$$ to cleanoff the back of the cone.

So now I am ready to glue, wish me luck! Oh and I do not have a 30 Hz source ready and I am doing it by hand. If the movement produces no sound, then that is it.

Yank

[bigyank]

Funniest part is the woofers are still available on the JBL parts list for a measley 148.16 each. :D


Yank

[mech986]

In lieu of a 30 Hz source (I use 50-60 hz myself as these small woofers don't need to move at 30), you might just consider a good recording (or looped wav/mp3) that has some low bass content - you are using this to just get current and signal into the voice coil to keep it centered, so you don't need a really low signal and you don't need high volume. Really, just enough to see and hear the cone move freely without scraping. The signal itself will keep the VC aligned if the cone is moving.

Best of luck, if yours works, I'm contacting TG for some surrounds too!

Regards,

Bart

[bigyank]

Downloaded http://mdf1.tripod.com/test-tones.html and burned 60 minute 50 Hz signal and will continuous play this through a CD player and a 40 watt/ch amp at low volume. Tomorrow morning is the moment of truth!


Yank

[pelly3s]

for refoaming i have a DC supply at like 2 volts with a polarity switch and it makes centering a whole hell of a lot easier. i also use the same CP Moyen glue you get with a recone kit. So it makes like easy

[norealtalent]

for refoaming i have a DC supply at like 2 volts with a polarity switch and it makes centering a whole hell of a lot easier. i also use the same CP Moyen glue you get with a recone kit. So it makes like easy

Sounds like a great idea. Would you please elaborate for this untalented monkey?
Thank you, Dave :dont-know

[pelly3s]

what i did was take a small 200mA variable DC supply and wire it to a dpdt switch so i can reverse the polarity of the output, and that is just wired to a pair of binding posts so i can use an assortment of leads off of it for multiple purposed. it then moves the cone assembly up or down depending on the polarity you have selected. now on certian jobs and outward movement helps more than on others. you will hear humming sound coming from the speaker and when it is rubbing you will hear sort of a rattling sound. just move the cone until it is centered and then let the glue dry

[bigyank]

I have put the woofers aside for the moment and started looking at the tweeters. I am now in posession of a 2nd pair (thanks Duaneage) so here is my question.

The original 034 screens are silver, the ones I purchased from Duaneage are black. I kind of like the look of the silver ones but first glance is these are a bugger to open or better yet open with the intent to close again. Should I even bother?

Yank

[duaneage]

Use a dental pick or toothpick to pull the rubber gasket from the groove where the screen sits. Practice on the bad tweeter first.

[bigyank]

Duaneage thanks! I will have to get better light to do this. Will be trying tomorrow night. Wish me luck!


Yank

[duaneage]

If you wet the rubber gasket with a little silicone spray it will go in easier and allow you to position it so it lays flat

[bigyank]

http://home.comcast.net/~jklorenzon/jbl.html

I am working on that tonight. Above link is a big picture of the old (left) and new (right) tweeterss. The flash washed out the painted plastic on the right tweeter. Wish this forum had a voting button for the following. My vote is silver screen. Date code on my originals is 5/83. The donors are 9/02. Both are 034's:D

I have dental pic in hand, have some DeOxit and off I go! Wish me luck!

Yank

[norealtalent]

what i did was take a small 200mA variable DC supply and wire it to a dpdt switch so i can reverse the polarity of the output, and that is just wired to a pair of binding posts so i can use an assortment of leads off of it for multiple purposed. it then moves the cone assembly up or down depending on the polarity you have selected. now on certian jobs and outward movement helps more than on others. you will hear humming sound coming from the speaker and when it is rubbing you will hear sort of a rattling sound. just move the cone until it is centered and then let the glue dry

Sweet! Thank you, Dave:bouncy:

[DavidF]

...
The original 034 screens are silver, the ones I purchased from Duaneage are black. I kind of like the look of the silver ones but first glance is these are a bugger to open or better yet open with the intent to close again. Should I even bother?

Yank

www.jblpro.com (http://www.jblpro.com) go to customer service...parts...misc. parts list.

Shows the unpainted screens listed as part 60424, $5 each. I have ordered directly from this site using the order parts screen. Sometimes, I do not get a response, most times yes.

David F

[duaneage]

I didn't know the plastics were painted, I thought they came that way :blink:

[bigyank]

No pic yet but the "merger" of the 2 tweeters are completed. Now I tried to do a surround for the first time and seems that the glue actually deformed the foam a little. Normal? Reason I ask is I couldn't get the 2 to bind. Do you really have to lay it in? I tried using a similar amount as shown in the thread (how-to) within this thread. No go! Since I couldn't get the 2 to match, is the surround toasted? Do I even attempt the other at this point? There is absolutely no space between the surround and back of the cone. The brush supplied seems too thick but I had already started when I realized it!

Help!!!!!!!!!!!!!!!!!!!!!

Yank

[Robh3606]

What kind of glue??? With the white glue it won't stick until it starts to dry. I do coats on both surfaces and let that dry a while until it tacks. Then I start working around the cone edge to get it to stick. The amber stuff I have never used so I can't comment.

Rob:)

[bigyank]

Amber. Monkey snot in color. I dripped a tiny drop where it shouldn't go and it is on there. The fumes are such that I wouldn't let my 9 year old around it!

Do youhave to "normally" slop it on both sides (cone and surround)?

[bigyank]

Pics are on their way but I have the first speaker completed. Replacement tweeter and new surround woofer. This is actually fun. Awaiting a 117H-1 from Oregon (Ebay) and I have a new surround waiting for it to complete the pair!

The scuffing you see on the bottom left is almost invisible in "normal" lighting. This is the least of my problems!

Yank