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

Gordon,

Fella, these FrankenJBLs rock. Tight and deep, with great mid-bass clarity and authority. So far, I'd put them in a category of JBL E-145, they have that same mid-bass clarity and character, with deep bass extension. That, is a huge accomplishment.

I have a lot more listening to do.. before I'd go further, but I like what I hear so far.. a lot!

For reference, they are currently installed in cabinets that are about 9 cu ft, tuned to about 25 or 26 Hz.
 
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That's what I was thinking would happen (or at least was hoping for). A true "jack of all trades" woofer that can do well in any application.

No, it doesn't have the sheer air-movement capacity of a W15GTi... but unlike the GTi, it can do midbass, and go up to well above 1KHz without problems. The GTi has a significant dip in the midbass/low mids, and a pretty bad break-up mode around 800 Hz (as can be seen in the response table above- look at the 103dB reading in that range), combined with a pretty strong rolloff above that point, which really limits its use as a 2-way driver... hence, it's not recommended for such.

But, the "2236" has ENOUGH excursion to seriously SLAM down to the low-20s in-room... so, it's a midbass driver, that doesn't NEED an additional subwoofer. And with the SFG motor, it's low distortion... so, running it up into the midrange is fine, since it'll stay "clean"...

In essence... with this, and the right horn, you can literally make a 2-way speaker that's capable of damn close to 20-20K response, and not really give up much of anything in-between. How many of THOSE are there out there, that don't cost a zillion dollars?

And, as for the comparison to the 2235- if I was to use the soft spider, I would have wound up with parameters that were MUCH closer to the 2235. I've done the sims with the same cone mass, just with higher compliance, in BassBox... and it does start to look much more like the 2235 parameters. But, in this case, that wasn't the goal... we WANTED to keep it a little "stiffer", so it could work well in the midbass too...

Regards,
Gordon.
 
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djnagle said:
Hey G, would these go up high enough to match with the eWave?
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With the QSC 152 waveguide and the B&C DE250, Selenium D2500TI-ND-OMF or Radian 450/475 horn driver, I'd think so. You might need to tweak the crossover point down a little, but I'd think it would work at least as well as a LE14...

I might hesitate to use it with the 'basic Ewave setup" (PH612 type waveguide and the Selenium D220Ti). It might push the low-end of the "low-budget" combo a bit... I would be a little afraid of winding up with a little 'harshness' in the 1KHZ region...

Of course, if you're going to build a woofer this "sophisticated", might as well "spend up" a little on the flare and horn driver too, right? :D

Regards,
Gordon.
 
Cosmos said:
For reference, they are currently installed in cabinets that are about 9 cu ft, tuned to about 25 or 26 Hz.
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According to WinISD, that should give an f3 of about 25Hz... BEFORE "room gain" is considered. F10 (10dB down) is about 19.5Hz. :thmbsp:

You might try raising the port frequency to 27Hz, for a little more "slam" at 50 Hz, if needed. However, I wonder IF it will be needed? :D

BTW: FWIW, it looks like this woofer in 9 cubic feet tuned to 26Hz, is a similar TYPE of alignment (i.e, ignoring the difference in the frequency range where rolloff occurs, the "shape of the curve" is almost identical), to the 2226 in its original form, in the JBL-recommended-and-used (the 4648A cabinet is one example) 4 cubic foot cabinet, tuned to about 45 Hz. It only goes almost an octave LOWER now. :D

Regards,
Gordon.
 
GordonW said:
No, it doesn't have the sheer air-movement capacity of a W15GTi... but unlike the GTi, it can do midbass, and go up to well above 1KHz without problems. The GTi has a significant dip in the midbass/low mids, and a pretty bad break-up mode around 800 Hz (as can be seen in the response table above- look at the 103dB reading in that range), combined with a pretty strong rolloff above that point, which really limits its use as a 2-way driver... hence, it's not recommended for such.

Regards,
Gordon.
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If you look a the chart, the W15GTi actually goes higher than a 2235. If you were to cross it over at 800 Hz, the additional volume in that area would be a plus reducing the "gap" at the crossover point. I do use 2235s in my mains and center crossed at 800 Hz to 2420 drivers, and yes, there is a gap in that range (that bugs the he-- out of me) that is not present when the W15GTi is used.

Besides, the title is "Super Sub" not "Super Mid Bass"
 
Sir.Byrd said:
What prevented JBL from making a driver with the same parameters as your 2236H?
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Nothing, other than probably lack of demand (or perceived demand).

The W15GTi mentioned here, is pretty similar in concept... it, in a somewhat over-simplified sense, is like a 2242 motor assembly with a heavy 15" cone with rubber surround.

It's just that they were no longer making 15" studio monitors or 15" home sub cabinets... so, they really didn't need a foam-surround 15" anymore...

Regards,
Gordon.
 
toddalin said:
If you look a the chart, the W15GTi actually goes higher than a 2235. If you were to cross it over at 800 Hz, the additional volume in that area would be a plus reducing the "gap" at the crossover point. I do use 2235s in my mains and center crossed at 800 Hz to 2420 drivers, and yes, there is a gap in that range (that bugs the he-- out of me) that is not present when the W15GTi is used.
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Sounds like a little fiddling with the low pass (reducing the order and/or raising the frequency- maybe like 1200 Hz low pass) could result in an acoustic function that would get up to at least 800 Hz easily, if not 1100 or so. In fact, just letting the 2235 roll of on its own, looks like about a 12dB/oct. 1100 Hz lowpass...

In any case, if you follow the data throughout the range from 100-1000 Hz, the 2235 is MUCH smoother than the W15. Looks like the 2235 goes from a max of about 100.7 dB to a minimum of 96.6 (about 4dB variation max, ANYWHERE in the range), where the W15 varies from 92.3dB to 103.0dB (over 10dB variation, with a 6dB "bounce back" from the 92.3dB @ 1000 Hz to the 98.8dB @ 1200 Hz). That's rather a steeper roller coaster compared to the remarkably flat response of the 2235...

So, to further iterate on the answer regarding E-waving these... with a acoustic response of about 1200 Hz to the QSC152 (with maybe the B&C DE250 on it)- which probably would require about a 2500-2700 Hz highpass, compared to the normal 3KHz (IIRC) highpass on the normal Ewave highpass section- and maybe a second-order lowpass of say, 2-3KHz or so on the 2235H (let the natural rolloff of the 2235 start the acoustic rolloff, and "finish it off" an octave higher with the electrical lowpass) instead of the 1.5kHz "normal" E-wave lowpass, you may well have something very nice...

In any case, I would recommend MEASURING the "2236" in-box before doing any of these crossovers. The "2236" appears to have slightly less inductance than the 2235 (which may extend its upper end response just a tad). That would definitely indicate some slight changes...

Also, as concerns the use of the term "sub"... well, a W15GTi is about $350 to $500 or so. The "2236" can be built for the cost of a dead 2226 (probably less than $100), and an aftermarket recone of the frame ($85 or so). For less than $200, in any case. In rough terms, you can have TWO of these for the cost of ONE W15. And the two of them can probably function on less power than a SINGLE W15 will require, and provide significantly more SPL than a single W15...

Regards,
Gordon.
 
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GordonW said:
In fact, just letting the 2235 roll of on its own, looks like about a 12dB/oct. 1100 Hz lowpass...

Also, as concerns the use of the term "sub"... well, a W15GTi is about $350 to $500 or so. The "2236" can be built for the cost of a dead 2226 (probably less than $100), and an aftermarket recone of the frame ($85 or so). For less than $200, in any case. In rough terms, you can have TWO of these for the cost of ONE W15. And the two of them can probably function on less power than a SINGLE W15 will require, and provide significantly more SPL than a single W15...

Regards,
Gordon.
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You NEVER want to let a 2235 roll off on its own. It's a beast and gets really bumpy just above the top of my testing and you can see it at the upper range. JBL put the top of the range at 1KHz.

I paid $250 for my W15GTi and that's what they were going for all day on the 'bay

If you can find a 2225 basket for $50, a JBL 2235 recone is currently $232 at Orange County Speaker. Anything else is just not a JBL and your just kidding yourself if you think it is. BTW, the 2235 aftermarket cone is $145 at OCS.

The W15GTis do need (and can take) a lot of power. But if you look at the sub frequencies of interest for a subwoofer, you see that the speaker is on the order of 6 dBL louder than the 2235 (both as measured from the 200 Hz reference frequency). That represents a factor of one fourth of the power needed relative to the 2235, so in the sub range it's not so inefficient when compared to a 2235.
 
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toddalin said:
You NEVER want to let a 2235 roll off on its own. It's a beast and gets really bumpy just above the top of my testing and you can see it at the upper range. JBL put the top of the range at 1KHz.

I paid $250 for my W15GTi and that's what they were going for all day on the 'bay

If you can find a 2225 basket for $50, a JBL 2235 recone is currently $232 at Orange County Speaker. Anything else is just not a JBL and your just kidding yourself if you think it is. BTW, the 2235 aftermarket cone is $145 at OCS.
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Your data indicates that the W15 is far more "bumpy" than the 2235, inside the passband. The 2235 actually has a relatively monotonic rolloff (i.e, it doesn't "bounce back" much at all once it starts rolling off), where the W15 has a noticeable large peak at 800 Hz... then it rolls off, then it comes back, then it rolls off again. I can notch out the upper end of the 2235 (above 1200 Hz) if needed, easily... but it's REALLY DIFFICULT, without a parametric EQ, to flatten out a response that goes up-and-down-and-up-and-down, WITHIN the desired bandwidth...

And ask Cosmos if he's kidding himself... :scratch2: Seriously, many of the parts we get, have the SAME NUMBERS stamped on them as the latest JBL "factory" kits. Coils wound by the same factories. Cones made by the same factories, on the same jigs, in many cases.

The day where people could poo-poo on the aftermarket reconing parts industry are OVER, and those who have that chip remaining on their shoulders, should really just get over themselves, and let us who actually want to MAKE NICE THINGS ourselves, do it. This site (AK) is about "no attitude"... we really don't need someone's prejudice against "non-JBL parts" here, really...

Regards,
Gordon.
 
GordonW said:
..............

The day where people could poo-poo on the aftermarket reconing parts industry are OVER, and those who have that chip remaining on their shoulders, should really just get over themselves, and let us who actually want to MAKE NICE THINGS ourselves, do it. This site (AK) is about "no attitude"... we really don't need someone's prejudice against "non-JBL parts" here, really...

Regards,
Gordon.
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I completely agree! Well said Gordon. I have done several "name brand" recones as well and am satisfied all the components were of top quality- EV, JBL, CV quality at that! High temp edge wound coils, sturdy light weight cones, etc.

Thanks for stepping in with your opinion here Gordon could not have said it better myself........
DC
 
Hey Gents.. :-)

Personally, I really don't know that much about the dynamics of driver design. It would be a waste of bandwidth for me to discuss parameters, etc.

Further, I have never personally tried W15GTi. I believe that is Scott likes it, it must be a great driver. I have confidence from reading his posts for years that he has a good ear.

In general, I like a nice tight, articulate bass. I hate "one note bass" about as much as I hate Slurring HF. I want a very musical bass. I'd like to say concert like, but most large venue concerts are horrible. I recently saw both Ian Anderson and YES in concert. The acoustics at both were bad. YES was horrible, pure mush. I look forward to the day that I can journey to Coney Island to hear Scott's system.

However, I have tried many, many drivers over the last 35 to 40 years. Some of my favorite 15" drivers are the JBL 2226, JBL E145, JBL 2235/2225, TAD TD-1601, Acoustic Elegance Lambda TD-15 series. but each has trade-offs.

The cabs that now hold the "2236" previously had E145, 2226 and 136A in it.

In my opinion, this "2236" driver has significant merit. Is it the best subwoofer? Maybe not. Is it the best midbass woofer? Maybe not. But, it is a player. It is worth experimenting with. Currently, I am running AE Lambda TD-15X (probably my favorite all-around woofer) in my main system in 6.5 cu Ft cabs with adjustable tuning. I can tell you that I am going to swap this driver in to see where it takes me... It seems to have a great balance of extension and clarity. From listening to it so far, I suspect it will be able to more than hold it's own against the Lambda. We'll see.

I also suspect that I will be sending more 2226 frames to Gordon for this configuration, if I am right.

It has serious promise.
 
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Mega E-wave

djnagle said:
Hey G, would these go up high enough to match with the eWave?
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I am using a 2235 in my FrankenVals http://www.audiokarma.org/forums/showthread.php?t=335874 at a crossover point of 1K and they sound pretty damn good. I think the 2236 would work very well with the Z19 crossover http://www.audiokarma.org/forums/showthread.php?p=4231354#post4231354 at 1.2K. This crossover is almost perfect for the JBL 2452H-SL on PT-F95HF wave guide - yes I have heard them before. Not exactly 'Econo' by any means but it is in the spirit.
Let's not jack the prices up over at that auction site for 2226 frames :D
 
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GordonW said:
Seriously, many of the parts we get, have the SAME NUMBERS stamped on them as the latest JBL "factory" kits. Coils wound by the same factories. Cones made by the same factories, on the same jigs, in many cases.
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The same way I wouldn't tell that all aftermarket recone kits are bad, I wouldn't either say that they are all good. It's not difficult to notice crappy cones with that worm-like texture. All the aftermarket diaphragm that I removed from used 2402/04/05 tweeters were crappy in sound... and 6db under.

But I am curious at what brand of aftermarket recone kits for 2225/2226/2235 and 2240/2242/2245 is "that" good and so similar to original JBL at half price. Not being original doesn't bother me, as long as the quality and sound are exactly the same.
 
GordonW said:
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.
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:lurk: (With an empty 4518)
 
GordonW said:
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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tarior said:
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.
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koseltri said:
Does the 2245H work in this scheme?

Edit: Maybe not, Short Xmax like the 2241.
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I certainly don't have the knowledge or background Gordon has, but from personal experience, the 2245H surround doesn't quite limit xmax enough to prevent the VC from coming out of the gap. BTDT unless I did the recone improperly. Certainly a longer VC is a potential solution, assuming there's enough bottom gap in the motor, and maybe that's what the 2242H has?
 
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