PDA

View Full Version : JBL 2226H surrounds stiffen over time ?



Erik10
12-27-2015, 04:59 AM
Hi.

On my 2226H's the cloth surrounds seems very stiff. The drivers are most likely 20 years old.
The cloth surrounds seems to have a finish applied to them, and they look very much the same as i see on pictures that people are posting of their 2226H's.
I'd like the drivers to play with more detail and dynamics, the sound seems somehow muffled. They can play music and sine vawes etc. without scratching or distortion. They just sound ... well, muffled.
Does the surrounds on 2226H tend to stiffen over time ?
Does anyone have experience softening them up by applying lubricants or other fluids ?
Iv'e read that brake fluid DOT 3/4/5 can be applied to eg. LE14A.
I'm considering silicone - the thin flowing fluid that is used to apply to eg. door seals on cars.

Since there is a risk of ruining the drivers, I'd like to know if you have experince with such treatment on 2226H or drivers with identical surrounds, before I start out.


Best regards,
Erik

ivica
12-27-2015, 07:27 AM
Hi.

On my 2226H's the cloth surrounds seems very stiff. The drivers are most likely 20 years old.
The cloth surrounds seems to have a finish applied to them, and they look very much the same as i see on pictures that people are posting of their 2226H's.
I'd like the drivers to play with more detail and dynamics, the sound seems somehow muffled. They can play music and sine vawes etc. without scratching or distortion. They just sound ... well, muffled.
Does the surrounds on 2226H tend to stiffen over time ?
Does anyone have experience softening them up by applying lubricants or other fluids ?
Iv'e read that brake fluid DOT 3/4/5 can be applied to eg. LE14A.
I'm considering silicone - the thin flowing fluid that is used to apply to eg. door seals on cars.

Since there is a risk of ruining the drivers, I'd like to know if you have experience with such treatment on 2226H or drivers with identical surrounds, before I start out.


Best regards,
Erik

Hi Erik10,

I am not specialist in that filed, but as 2226 has cloth suspension, I would expect that applying PVA glue
(white glue, latter transparent, usually used to glue the suspension to the diver frame) on its suspension would be enough.

2226 suspension is not so soft as expected, You can see its free-air resonance frequency is round 40Hz (Vas=175 lit)

regards
ivica

PoulM
12-27-2015, 01:07 PM
I have about 20 2226s with widely differing serial numbers in stock and have had professional involvement with many dozens more units. I have never experienced any major changes, neither stiffening or softening, but as we both are in Denmark you are most welcome to try one unit for comparison. But as Ivica says they all feel very stiff to the touch.
We are Dansk Audio Teknik in Aarhus
PoulM

jpw
01-08-2016, 01:34 PM
I have a pair of 2226H's that are 13-14 years old that I used in a tri-amped home system. I have not noticed a visible or mechanical change on mine but I do not have new ones to compare to. Regarding it's sound, in my opinion the 2226H sacrifices not only deeper bass but some clarity and linearity in it's response particularly above 200-300hz. This is done in the name of higher sensitivity, higher SPL capability and ruggedness. Therefore I believe it's design better suits pro demands than home audio. If I had it to do over again, I would use a JBL 15 inch medium sensitivity driver. They are flatter into the midrange with greater naturalness and extended usefully deeper in the bass so that no EQ or subwoofer is generally needed. This being said I get more than respectable sound from the 2226H when using some EQ for room problems and to help it smoothly get to the midrange driver. If yours sound really muddy I would recommend measuring your speaker/room response to look for errors that are more likely the cause of the problem than the shortcomings of the 2226H itself.

NickH
01-09-2016, 11:25 AM
If I remember correctly the brake fluid trick is for lansaloy surrounds. Plus only dot 4 and 5 fluid are silicone. Dot 3 is not.


I don't see how the surrounds on a 2226 would stiffen over time though since there's no wet treatment on them. The coating that's used on the surrounds does not look like pva. Its more viscous then pva, at least what I've have.


I've also read you can clean surrounds with acetone and then retreat them. I don't imagine its an easy process.

Nick

Wagner
01-14-2016, 08:31 AM
Applying any new material to an already "stiff" surround is in no way going to help you

I'd run a steady state 30Hz tone (or similar) through them over night and see if they improve subjectively

OR

As I mentioned in another thread: mix up some 99% alcohol and water, 50/50
Support the cones with some polyfil, little bits of sponge or whatever you have on hand tucked between the cone and basket, NOT TOO MUCH, just enough to support the cone

Brush the surround in a single wet pass, thoroughly wet but not sopping or dripping, ONE PASS and let them dry overnight and then see what you have. Don't "scrub" the compliance. Don't wet the cone

If you are convinced it is the woofer's fault that they sound "dull" and you add more PVA material to the surround you'll have even more "dull" when you're done; don't add any more mass or damping to the cone!

You may do what I suggest with a stronger solvent, but I would try the alcohol first (milder) A stronger solvent may also backfire and make things worse (think reconstituted adhesives/changing the original material)
What I'd really suggest is finding your problem, I have never had a JBL with cloth compliance become "too stiff", in fact, a couple of times with 123As it was just the opposite

Good luck with your remedy, whatever it turns out to be