Can a JBL 2225h really become a 100% 2235h?

I have spent the past few days searching this topic and I kinda hit a wall of contradictions.

For sure the JBL 2225h and 2235h have the exact same basket, and therefore a 2235h recone kit on a 2225h should make it a 2235h. Some will say the 2255h becomes a 100% exact 2235h. While others will say that the 4" motor is slightly different, and that therefore it will not become a perfect equivalent.

So... What's the last word on the subject? The topic is not about if a 2235h is or ain't a good sub. It's about the recone process.

Thanks in advance.
 

dogbert

Member
2004-09-15 3:54 pm
Utah
Yes, if you rebuild a 2225H motor with the 2235H kit you can have a 2235H, end of story. The basket, magnet, clearance and gap are identical. There are several other JBL motors or baskets that are not identical. The only difference is the label on the back of the magnet. You can verify this by doing a search at the Lansing Heritage website, I wouldn't trust any other source on this topic. This all assumes you are buying a genuine JBL recone kit.

You can also build a 2234H with a 2225H motor by buying the 2235H kit and not installing the mass ring under the dust cap. I hope this doesn't confuse things.
 
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If the gap and motor (magnet) are indeed 100% the same between the 2225 and the 2235, then a 2235 recone, would make a 2225 a real 2235 functionnally. Except for the rear tag obviously. The reason I am asking is that 2225s area dime a dozen, and real 2235 are pretty rare. I just bought a real 2235h out of a recording studio, that has been treated to a new JBL-sourced suspension. The driver is like new. But I would like to buy at least another. If not three others.

If I were a collector, I would not do a "transplant". But just for sound, then the recone should do the job if the end result of the swap is a perfectly identical 2235.

BTW The mass ring is what gives the 2235 the low Fs (and also lower power handling due to the extra cone excursion).
 
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This is covered to helll on other forums.Yes. FYI im getting custom cones made by the same guy who said my factory recone kits are cr*p. :D

You are correct. It's been beaten to hell. And as I previously stated, the conclusions were not unanimous. Half of the poled "experts" will say the recone will be excatly like a 2235, 50% will say it is not exactly the same.

And as I am a brake engineer and design components for racecars, I know very well how inaccurate people can be, just reporting hearsay as truth. Believe me on that :D
 

francolargo

Member
Paid Member
2007-03-12 8:07 am
Twin Cities, MN
Now ever more interesting... I have a 'cone guy' whom I simply trust, and I generally just play his speakers without asking questions...

One can find lots of dubious sources of 'factory' parts. So, are the factory recone parts cr*p because of their age or original design (or both)? ... and how is the difference between the stock and custom parts sonically revealing? And at what SPLs? 2235H was never a super-high output design, IMO.
 
and how is the difference between the stock and custom parts sonically revealing?

I would bet you the aftermarket kits don't have the mass ring that goes under the cap. If it doesn't there is a very good chance the cones mass will be too low and FS will be too high. They spec them at 20hz and the factory recone kits come in a little lower say 18-19hz on the pair I measured.

Rob:)
 
About to finish a prototype with 2235h + bass reflex + 6.9 cubic feet. But...
- The driver has 20Hz resonance
- The enclosure has 26Hz resonance to that driver.
http://www.ajdesigner.com/phpsubwoof...y_equation.php

Shoud I tune the port length to the driver, or to the enclosure? 20Hz or 26Hz Something tells me 26Hz but I need confirmation.

Actually, I will check if one 4" port is enough, as I could make one port tuned to 20Hz, and the other ports (the baffle has provision for two ports) could be tuned to 26Hz. I could plug one or the other and test what works best.
 
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francolargo

Member
Paid Member
2007-03-12 8:07 am
Twin Cities, MN
Sorry, I coudn't find Rob's comment.

My 2235h are in enclosures of about the same volume and IIRC I tuned them above fs - ~25Hz? The legacy JBL info suggested 30Hz IIRC. I have no problem with the rare program material below that - at least in home use. Suggestion: cut the baffle ports carefully so that you can press fit and test different lengths of port tubing. I'm using 2 3" PVC tubes. FWIW, I cross mine over with 4th order Butterworth filters at 165Hz using Thuneau frequency allocator lite. Compared to freeware IIR XO's, the Thuneau filters offer more punch and a bit more 'smoothness'. Since I got that software I have only set things up by ear - I should record sine wave sweeps and see if there is room for improvement... Bottom line: Enjoy!!!;)
 
Rob's reply.
2235h + bass reflex + 6.9 cubic feet. But...

JBL's engineers sure knew what thy were doing when they made the B380 subwoofer which used a 2235h in a 5cf enclosure, but they were not the only link in the project. Between the marketing guys (the enclosure should not take up too much volume in a small appartment or it won't sell) and the bean counters (please design the enclosure so that it fits one 4'x8' sheet of presswood or we may lose profitability), a great idea is often diluted. Therefore, why not make something different? 5 cubic foot 's resonance is 30Hz. 6.9 cubic foot's is lower, 25-26Hz. Going to a bigger enclosure will drop a bit on efficiency, but will slightly increase the very bottom end. Anyway, it is only a weekend experiment, and if I don't like it, I'll trash the cabinet. ;-)

As for the ports, I have two openings and I'll tune each one to a different frequency. 20 and 26Hz. Then I will have the choice between one and the other, and will test what works best.
 
I can run the sub thru an active crossover and digital eq. Both with limiters. BTW I have finished painting and clearing the beta-enclosure on Sunday afternoon. One port is tuned to 20Hz (driver resonance) and the other is tuned to 26Hz (enclosure resonance). BOth with a small 1/2" radius. I am ready to drop the 2235h on the front baffle, and only waiting from my supplier to get back to me about the mounting clamps.
 
Quick partial update. I connected the 2235h to my active crossover feeding an ADCOM 5500, with cut-off at 70Hz. and I am in love. I switched bass reflex ports between 20Hz and 26Hz, and I think I prefer the 20Hz as the bass feels better, but it will take time before I can decide and there might also be some psycho-acoustical placebo syndrome too ;-). The single 2235h in a 6.9cf bin has more deep bass than a pair of 12 inchers in 3cf enclosures. The final design will be with 6.9cf enclosures, nothing smaller.

I found a local source with 90 (ninety) 2225h for sale and have asked to look for three units with bad suspension at rock bottom price so that I can recone them to 2235h. Dude also has 40 (fourty) 2405 for sale... Hmmm... All components come from Montreal's Jazz Festival equipment.
 
Another update. I now run a pair of 4530 bassbins with 2225h drivers on an ADCOM 5500 (overall an okay amp. Not more. Punchy around 40-50Hz but not much down 30Hz) AND the 2235h sub driven by a Yamaha P2200 (maybe the sweetest power amp I ever had).

The 4530s alone have great kick but no bottom. The 2235 sub has great bottom but no kick. Therefore they complement each other very nicely. Now looking for another P2200 to replace the Adcom. ;-)
 

Rewind

Member
2009-01-18 7:42 pm
Oslo
Try the E-120 also, instead of the 2225. Looks like you have too many subs on top of each other. But yeah, I love to stack drivers on top of each other. I bet the bass was/is something else.

Five years later... Anyway, great jazz festivals you have in Montreal! I was there in 2013.