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View Full Version : JBL LE8T-2 two questions.....



Dylanl
10-02-2016, 01:58 PM
1) who make a good foam kit for these speakers of of a JBL Aquarius?

2) when reading Ohms across speaker terminals these 8 ohm speakers read a) 5.3 & B) 5.8 what does this reading really mean? ( Voice coil )? and why don't they read 8 ohms? Does this reflect the health of the driver?


Thank you

BMWCCA
10-02-2016, 02:35 PM
Google Rick Cobb for surrounds. Recommended by anyone here who has bought from him.
http://www.audioheritage.org/vbulletin/showthread.php?28013-Rick-Cobb-Looneytunes-Replacement-Foam-Rings

Your DCR reading means most likely the drivers are fine. If they showed open, they you should worry. Resistance varies under load and I suspect what you're seeing is pretty normal for static resistance. That they're both the same is a good sign.

Don C
10-03-2016, 07:16 AM
If these were originally the white surrounds, there are specific replacements on ebay. I haven't heard any but they sure look nice.

http://www.ebay.com/itm/182293768823?

grumpy
10-03-2016, 08:25 AM
They do look nice, ... although on an aquarius type system, there might be less visual interest/concern
(but you would still -know-) :)

Dave Cawley
10-03-2016, 08:57 AM
1) when reading Ohms across speaker terminals these 8 ohm speakers read a) 5.3 & B) 5.8 what does this reading really mean? ( Voice coil )? and why don't they read 8 ohms?

You are measuring the DC resistance. 8 ohms is the AC impedance normally measured at 1Khz. Your readings are just fine.

Regards

Dave

Dylanl
10-03-2016, 09:04 AM
Last question, this white gasket is so hard to get off. What will releasae it? Lacquer thinner has no effect

Dylanl
10-03-2016, 09:05 AM
You are measuring the DC resistance. 8 ohms is the AC impedance normally measured at 1Khz. Your readings are just fine.

Regards

Dave

Funny because the tweeters at 8 ohms have similar findings

Dave Cawley
10-03-2016, 09:30 AM
Funny because the tweeters at 8 ohms have similar findings

Funny ?

grumpy
10-03-2016, 01:21 PM
"funny" as in "odd" to someone that has yet to expand the concept of impedance from nominal to
a value that varies (sometimes wildly) over frequency.

The nominal value being something selected (e.g., minimum) or averaged over an operating frequency range
that represents typical use or limitations. A bass driver may have a maximum impedance of 100 ohms, a DC value
of 6 ohms, a minimum mid-band dip at 4.5 ohms, and then start rising again as frequency increases... and be called
a 4 ohm driver (nominal). If interested, check out a particular driver in the technical section and have a look at it's
impedance vs frequency plot.

Dave Cawley
10-03-2016, 02:47 PM
Ah yes, but then to the uninitiated all electronics must seem funny ? Learning from the Internet is fraught with problems. University tutorials on the net tend to be the best but often difficult to understand.

www.aes.org/aes/davecawley (http://www.aes.org/aes/davecawley)

Dave

grumpy
10-03-2016, 04:38 PM
Indeed ;)

Nice to meet you Dave.

Dylanl
10-04-2016, 08:43 AM
"funny" as in "odd" to someone that has yet to expand the concept of impedance from nominal to
a value that varies (sometimes wildly) over frequency.

The nominal value being something selected (e.g., minimum) or averaged over an operating frequency range
that represents typical use or limitations. A bass driver may have a maximum impedance of 100 ohms, a DC value
of 6 ohms, a minimum mid-band dip at 4.5 ohms, and then start rising again as frequency increases... and be called
a 4 ohm driver (nominal). If interested, check out a particular driver in the technical section and have a look at it's
impedance vs frequency plot.

Exactly!

droh
03-07-2017, 08:05 AM
I'm a little late to the party but I have had some experience with the LE8-T2 and the white foam surrounds on ebay. They work great, I have done three pairs now. Visually they look spot on (though it's true no one will see them) and the fit is perfect. And once done the sound is great, I am very amused whenever someone lists a pair of Aquarius 4s and says "they still sound great" unless those old LansAlloy surrounds have been replaced there is no way you are hearing the full potential of these speakers. I also believe a crossover recap is essential, every pair I have worked on I found the caps were way out of spec.

Regarding getting the old surrounds off, they are stuck on there good, and the cone on the LE8-T2 is very very thin. So the most important thing you need is patience. I have found that MEK will soften the old surround material enough to be able to rub it off the cone itself. And it will also remove the glue from the frame. So when I do a pair I completely clean everything off the frame and just get it down to the glue on the cone, trying to get the glue off the cone could actually tear the cone.

Dave