K120 reconed with E120 kit = ??

[johnaec]

I've got two K120's that have been reconed with E120 kits, and using paper domes insted of the aluminum.

My question is this - Xmax for K120's is listed as 1.52 mm and for E120's is 3.05 mm, roughly twice as much. I'm assuming the E120 voice coil windings must be twice as deep as the K120 - correct? Does this mean I should expect the same Xmax out of the K120 with the E120 kit? I don't have any of the physical values, (Plate, VC depth, etc.), to manually check, but would like to know if I should mainly be using K120 or E120 specs for cabinet design, etc..

Thanks for any info - John

[edgewound]

Use E120 specs, because it's now essentially an E120. Voice coil windings are the same.

[johnaec]

If voice coil windings are the same, how does the E120 get twice the Xmax?

John

[Alex Lancaster]

:) According to the 1980 Service manual, both the K and E use the C8R120, so:

A.- They put a suspension and spider that allowed more travel, and the top plate was thick enough, with or w/out a deeper voice coil.

B.- A typo.

C.- ????????

[edgewound]

If voice coil windings are the same, how does the E120 get twice the Xmax?

John

If you think about it...a silly millimeter and a half is not that much...but the E120 has a little better bottom end. E series has more excursion than K series, and better power handling.

[johnaec]

If you think about it...a silly millimeter and a half is not that much...but the E120 has a little better bottom end. E series has more excursion than K series, and better power handling.A millimeter and a half is still 100% greater, (twice as much), as the K120. Equates to potential 3db greater output.

I'm just trying to get a base value to determine whether to move to something other than these K/E120's...

John

[edgewound]

A millimeter and a half is still 100% greater, (twice as much), as the K120. Equates to potential 3db greater output.

I'm just trying to get a base value to determine whether to move to something other than these K/E120's...

John

What's your application? Sound reinforcement? Mains? Stage Monitors? Home Theater? The K120 sensitivity is rated at 101dB, the E120 103dB.

[johnaec]

Stage monitors. I'm trying to decide if it's worth picking up an inexpensive pair of 2202H's I have access to and replacing the K/E120's. If I'm getting E120 performance right now, I think I'll pass on the 2202H's because the difference in performance isn't that much. But if I'm only getting K120 performance, the 2202H's would be worth changing to.

John

[Lancer]

Here, this should confuse you even more:

http://www.jblpro.com/pub/components/eseries.pdf

[johnaec]

Ha Ha - thanks, Lancer... Now I've got 2.5 mm Xmax to add to the mix. Nothing like consistent info from JBL...

I should probably just chuck this stuff and go for the neodymium based monitors like Bo's... (lottery help needed...)

John

[edgewound]

Stage monitors. I'm trying to decide if it's worth picking up an inexpensive pair of 2202H's I have access to and replacing the K/E120's. If I'm getting E120 performance right now, I think I'll pass on the 2202H's because the difference in performance isn't that much. But if I'm only getting K120 performance, the 2202H's would be worth changing to.

John

I guess it'll depend on what you're using for the HF driver...the K/E120 will have greater overall output and more high end for higher crossover point. Most vocalists will prefer the cut through of a horn crossed over at around 1500Hz. Once you start to get into 3K + range like the 4602 Cabaret the bullet can get out of control with feedback problems...and lack the full bodied midrange of a good compression driver like the 2425, 2420, etc., that a vocalist really needs to hear himself with detail. Also the 2202H will be a little smoother sounding, but a little less efficient. Might end up 6 to 1, half-dozen to the other with these two twelves...I'm sure the K/E120 will do just fine...unless yer wantin' them for a guitar amp:bouncy:

[Tom Loizeaux]

I have a vintage pair of Sunn floor monitors that I "upgraded" a few years ago by useing a K120 and a 075 bullet. They really kick! ...so much so that I just built a clone pair of these cabinets (I think mine are better made) and put in the E120 and 2402H. These REALLY kick! The E120s are slightly louder and seem to have more low end and a little more bite.
I think this combination of musical instrument 12s w/ aluminum domes mate with the JBL bullets very nicely.

The photo shows my new "clones", one in the foreground and the other in the background, with two original Sunn monitors in the middle ground (w/JBLs added).

Tom

[edgewound]

Those monitors look great Tom, and I bet they do kick....I was just expressing my personal preference for the compression driver in the stage monitor, rather than the bullet.

The D-K-E120/130 does work great with the 075/2402...just not my first choice for monitors when I sing.

Nice work:)