Building a JBL 15" "Super Sub" driver on the relative cheap!

GordonW

Speakerfixer
Subscriber
Just had to share these results... this is pretty awesome! :D

I've been working on a project for Cosmos here... he sent me a pair of JBL 2226H frames, that I converted to a "super 2235"... replaced the fabric-edge PA-woofer cone with the foam-edge "subwoofer" cone used by the 2235H. At the same time, I used an copper wire (instead of the aluminum-wire of the stock 2226) edge-wound voice coil with slightly longer winding (7/8" winding pack length, as opposed to 3/4" for the stock 2226) and a softer suspension (spider) than the stock 2226.

Well, the proof is in the pudding.

Tested the woofer using the Dayton WT3 this morning... here's the parameter set I got:

JBL 2226 Frame with 2235 cone and custom VC setup:

Fs= 30.95 Hz
Qes= .4164
Qms= 7.41
Qts= .3942
Vas= 5.607 cubic feet
Re= 5.264 ohms
Le= 1.18 (pretty admirably low for a 15- should have good HF extension!)
Mms= 171.5 grams
X-max= .35 inch (one-way!)
Sensitivity (1w/1m): 92.43dB
Sd= 132.7 square inches

To put it in perspective: in a 6.5 cubic foot enclosure tuned to about 28 Hz or so, this woofer is capable of 28.5Hz bass extension in freeair, BEFORE room gain is factored in! A stock 2235 only goes to 30.5Hz in this application.
Also, since this woofer has a GREATER X-max than the stock 2235, AND twice the power handling (2226 Vented Gap frame allows for 600w power handling, where as the stock 2235 frame with vented pole piece only allows for 300 watt RMS rating)... you can do the math there too.

Great thing is? It only costs a dead 2226 frame (from "that auction place" or wherever), and about ONE THIRD the cost of an OEM JBL 2235 recone kit, to build one of these! In fact, you CAN'T EVEN USE a stock JBL 2235 kit (C8R2235H, in JBL part number terms) in the 2226 frame (it won't line up- you'll wind up with an alignment train-wreck!)... but, by being able to pick-and-choose components, I was able to create a kit that was a PERFECT fit, and actually EXCEEDED the performance of the stock JBL driver!

I think this thing is going to be a true monster. I am looking forward to getting these woofers back to Cosmos, and getting reports on how much he's shaking stuff around in his house, using 'em... :banana: :banana: :banana:

Regards,
Gordon.
 
:drool:

Will you disclose the full 'recipe'
"by being able to pick-and-choose components, I was able to create a kit that was a PERFECT fit"
Or do I have to place an order? :D
 
:drool:

Will you disclose the full 'recipe'
"by being able to pick-and-choose components, I was able to create a kit that was a PERFECT fit"
Or do I have to place an order? :D
It sounds like a serious contender either way.

It's a genuine shame that we haven't had a speaker tech even close to Gordon's caliber in my area in many years.
 
Jbl 2236?

Decided to give this one a pseudo-official JBL number...

Since the 2226 is to the 2225, like this is to the 2235... I will therefore, refer to this hybrid driver as the JBL "2236". They've never used that number for anything else, so it should make a good nickname for this combination. :D

Regards,
Gordon.
 
I betcha I know which parts to use.:thmbsp::D If only I had some 2226 baskets.....
 
WOWIE ZOWIE Gordon!! Looks like you have really taken this driver to a "whole 'notha level". Great specs and work. I have recently got into driver rebuilding and can undestand the time and pride you must feel here! I did essentially the same thing with a couple of tired EV SP15a's.

Given the cone kits, spiders, surrounds, voice coils you can combine from I am surprized more "super woofers" have not been designed. Great to see you as that pioneer!

What is the roll off of of this unit?

Thanks for a great read. It gives me hope.
DC
 
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Good job G. Dan was telling me about these. It sounds like they will really rock the house. Maybe his wife will FORCE him into building an addition for a listening room.....one can only hope.
 
One other consideration-

For Cosmos, since he wanted an "all purpose" driver that would work either as a sub or as a midbass driver (i.e, in an Econowave or such), I used a "moderate" stiffness spider... in the middle of the stiffness range. This, combined with the fact that I did NOT add any mass (no mass ring) makes it where it will work well in pretty much any duty.

However... if someone wanted to REALLY go low, there is one notch "softer" (less stiff) spider, that would lower the resonance down to around 25Hz without any mass added, or close to 20Hz with a mass ring. With a mass ring, the driver would probably be around 90dB sensitivity... but would probably EASILY go WELL below 20Hz in pretty much any reasonably-setup room... if you absolutely must have maximum rumble. :D

Now, this all leads to the next question... what would happen with a 2242H 18" frame and voice coil, with a 2245 foam-edge cone and spider? 18" with close to 1/2" of X-max... hee hee hee...
 
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Now, this all leads to the next question... what would happen with a 2242H 18" frame and voice coil, with a 2245 foam-edge cone and spider? 18" with close to 1/2" of X-max... hee hee hee...

I'd be a little worried about tearing up the foam surround when someone started really puttin' the power to it. Unless you have a different cone in mind than the one I'm thinking of.:scratch2:
I have a 2241 basket here that I was originally going to re-cone as a 2241, but now you've kinda got me thinking of going in a different direction with it.
 
I guess you could use the stock 2242 cone, just with a softer spider and a mass ring?

Or... there IS a huge rubber-surround (I mean, the rubber surround is like an inch wide!) cone made for the PAS 2880 18" woofer... which is also sometimes used, IIRC, as an aftermarket replacement part in the Gauss 4883XR 18". Wonder if that might fit into a 2242 frame. :scratch2: Hmmm. Need to go see if I can compare cone depth...

One note about the 2241 basket- it doesn't have the extra-deep "bumped back" back-plate that the 2242 has. You can't go quite as stupid with the excursion, like you can with the 2242. You can get up to around maybe 9-10mm X-max, absolute tops, with the 2241... but probably over 13mm with the 2242, IIRC...

Regards,
Gordon.
 
Some of the 18" foam edge Cerwin Vega cones I've used have a nice 3/4" wide heavy duty surround. Much more substantial than the surround on a 2245 cone, but I've not measured one to see if it will work in a JBL basket.
JBL specs the 2242 as having 3/4" Xmax, with Xmech at 2" P to P. http://www.jblpro.com/pub/components/2242.pdf
It's quite a driver in its own right.
 
Just had to share these results... this is pretty awesome! :D

Well, the proof is in the pudding.

Tested the woofer using the Dayton WT3 this morning... here's the parameter set I got:

JBL 2226 Frame with 2235 cone and custom VC setup:

Fs= 30.95 Hz
Qes= .4164
Qms= 7.41
Qts= .3942
Vas= 5.607 cubic feet
Re= 5.264 ohms
Le= 1.18 (pretty admirably low for a 15- should have good HF extension!)
Mms= 171.5 grams
X-max= .35 inch (one-way!)
Sensitivity (1w/1m): 92.43dB
Sd= 132.7 square inches
Regards,
Gordon.

Your T/S parameters are off for a 2235. This is a 2235 tested using WT-2:

Revc = 6.0493 ohms
Fs = 18.9984 Hz
Zmax = 174.2604 ohms
Qes = 0.2613
Qms = 7.2665
Qts = 0.2523
Le = 1.2375 mH (at 1 kHz)
Diam = 336.5500 mm ( 13.2500 in )
ConeArea =88958.8296 mm^2(137.8865 in^2)
Vas = 400.7658 L ( 14.1529 ft^3)
BL = 23.1910 N/A
Mms = 194.6316 g
Cms = 360.5723 uM/N
Kms = 2773.3691 N/M
Rms = 3.1973 R mechanical
Efficiency = 1.0138 %
Sensitivity= 92.0594 dB @1W/1m
Sensitivity= 93.2733 dB @2.83Vrms/1m
 
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Gordon, I can't wait to hear these bad boys, but feel free to throw them in some boxes and play with them for a while if you want...

I think I am going to start looking for some 2242 frames.. :)
 
One other consideration-

For Cosmos, since he wanted an "all purpose" driver that would work either as a sub or as a midbass driver (i.e, in an Econowave or such), I used a "moderate" stiffness spider... in the middle of the stiffness range. This, combined with the fact that I did NOT add any mass (no mass ring) makes it where it will work well in pretty much any duty.

However... if someone wanted to REALLY go low, there is one notch "softer" (less stiff) spider, that would lower the resonance down to around 25Hz without any mass added, or close to 20Hz with a mass ring. With a mass ring, the driver would probably be around 90dB sensitivity... but would probably EASILY go WELL below 20Hz in pretty much any reasonably-setup room... if you absolutely must have maximum rumble. :D

Now, this all leads to the next question... what would happen with a 2242H 18" frame and voice coil, with a 2245 foam-edge cone and spider? 18" with close to 1/2" of X-max... hee hee hee...


I was just wondering...wonder what he could make of my four 2241H?
 
Would be better off using a W15GTi for sub use. These have more xmax than the FrankenJBL and kick butt over the 2235 in the ULF area in a smaller cabinet. But, they take lots of power. If desired, they will go out past 1.2Khz.

For this test, each woofer is in its own volume and each volume was tuned the same with each woofer in a 4 cu ft sub-enclosure with an 11" long, 4" dia port to the exterior and a similar port to a 2 cu ft center chamber between the two woofers that also had a similar port to the exterior (A three chambered enclosure with each exterior 4 cu ft sub-enclosure twice the volume of the shared common central 2 cu ft subenclosure).

The 2235 was later give the full 6 cu ft (the interior wall was removed) and the port shortened to 8", and the W15GTi restricted to just 4 cu feet, with a 13" long 4" dia port to the exterior (as shown in the photo) and it still kicks butt.

Revised_Center.jpg


Frequency W15GTI 2235 Difference
Hz dBL dBL dBL
1500 91.9 84.5 7.4
1450 93.7 78.9 14.8
1400 95.6 87.9 7.7
1300 96.4 89.2 7.2
1200 98.8 90.5 8.3
1100 97.9 94.2 3.7
1000 92.3 101.4 -9.1
950 93.1 101.8 -8.7
900 95.3 101.9 -6.5
850 98.1 99.0 -0.9
800 103.0 98.3 4.7
750 101.2 98.7 2.5
700 100.0 96.6 3.4
650 99.1 98.2 0.9
600 98.7 99.1 -0.4
550 98.1 100.8 -2.7
500 98.8 100.1 -1.3
450 98.8 99.3 -0.5
400 97.9 99.6 -1.7
350 99.0 98.9 0.1
300 99.2 99.8 -0.6
250 100.2 100.0 0.2
200 100.0 100.0 0.0
180 100.0 100.0 0.0
160 99.8 100.5 -0.7
140 99.5 100.3 -0.9
120 101.5 101.4 0.1
100 101.3 100.7 0.6
90 101.6 101.8 -0.3
80 102.3 101.5 0.8
70 103.1 101.6 1.5
60 104.3 100.9 3.4
50 103.8 99.5 4.3
45 101.0 96.9 4.1
40 98.0 90.4 7.6
35 97.0 89.7 7.3
30 96.4 89.6 6.8
25 95.4 90.4 5.0
20 93.4 89.3 4.0
 
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