2225 to 2235 refoam xmax question

[Artcore87]

After much research I bought a pair of 2225H's on ebay for $250 and $40 shipping.

For what I'm using them for (home hi-fi, paired with midrange horns and a ribbon tweeter, ~5+ cu. ft. vented enclosure, tuned to 25-30hz), I would prefer to use the 2235H, and I understand that these can be reconed to 2235H's, and I've seen the kits for around $70 each. These are replacing some 15" RTR woofers (http://www.parts-express.com/pe/show...number=303-422) that are currently in the cabinets. I bought these custom made speakers which have high quality mid and HF drivers and nice custom cabinets and very nice crossovers... the cheap woofer seemed out of place. However it actually sounds pretty darn good, and can make quite a lot of bass if asked to. But, I haven't heard the JBL's yet so who knows how big the difference will be.

Buuuut actually I need these to go up to around 800hz with a 6db slope from there, so I'd like to retain some of the midbass sensitivity and transient response of the 2225H, so my question is this. I've seen re-foam kits for 2235's for 30 bucks. If I change the 2225H to a foam surround, will it be exactly the same as the 2235 EXCEPT for the difference in moving mass? And, is this difference in mass due solely to the 35g mass ring? I would like to just refoam the 2225's and put a few layers of mod podge on the cones, front and back. for added stiffness and mass. This way i could increase the mass slightly but not all the way to where the 2235 is... I'd aim for about half-way.

My fear is that the 2225 with the refoam will not have as much linear xmax as the 2235. Based on JBL's specs the 2225 only has 5mm while the 2235 has 8.5mm. So, the question is whether the difference is due to the surround or some other component difference.

Can anyone answer this question with certainty? If I don't get the 8.5mm xmax with a 2225 refoam and slightly additional mass, then I'll have to go all the way and recone them, because I want lots of clean bass.

Thanks!

[Robh3606]

Well there is only one way to be sure you are going to get a pair of 2235's. That's by using JBL kits to re-cone them. Those $70 kits are not the answer. You can jackass all around trying to mix and match but you are better off just bitting the bullet and getting the right kits.

If you want to retain more of the punch keep out the mass rings to make them 2234's. If want the most bass below 30Hz put them in to make 2235's. Just like anything else it'a all about choices and tradeoffs.

Rob

[Artcore87]

Well there is only one way to be sure you are going to get a pair of 2235's. That's by using JBL kits to re-cone them. Those $70 kits are not the answer. You can jackass all around trying to mix and match but you are better off just bitting the bullet and getting the right kits.

If you want to retain more of the punch keep out the mass rings to make them 2234's. If want the most bass below 30Hz put them in to make 2235's. Just like anything else it'a all about choices and tradeoffs.

Rob

Thank you for the reply, unfortunately however, you did not answer my question =/. But you did bring up another one... I thought the 70 dollar kits were for the real JBL part... I mean 70 bux per speaker is not cheap when its not even the whole speaker but just a replacement cone, vc etc.

I surely cannot afford to have JBL recone them... where can I get the real kit and how much do they cost? Given that the 70 dollar kit isn't the real deal and apparently few people here recommend them, would it be BETTER to leave it alone and just do as I said... change to foam surround and mod podge the woofer for added mass (and rigidity, more of a side benefit).

AND!!! the main question... will the 2225h with foam surround have 5mm or 8.5mm of xmax? If it's limited to 5mm by design, then eventually I will have to get true 2235h recones.

"We now offer a variety of high quality aftermarket reconing kits for select Advent, Bose, Cerwin Vega, EV and JBL speaker models! Pro kits use EDGE WOUND, USA MADE voice coils designed to EXACT manufacturer specifications. (Round wire for select home speakers). Cones, spiders, dust caps, and gaskets are matched to original specifications for size, weight, color and appearance."

Has anyone tried these or similar aftermarket recones? To be quite honest, unless they're outright lying in that description, then there should be VERY little difference between their parts and real JBL parts. I'm not a purist or an elitist and if its 1% off I don't care, period. These are custom mutt-speakers anyways, which is what a lot of DIY people have... so whats wrong with a custom mutt woofer? I don't care if it throws off the "specs" if in fact it simply shifts the specs to something that is still COMPLETELY ACCEPTABLE. Think about it... I wasn't searching for a 15" woofer with EXACTLY jbl's specs... I just chose them because it's known to be a good woofer. An aftermarket recone with SLIGHTLY different Fs or Qts etc. should in theory (if the parts are truly high quality and at least close to jbl spec, like stated,) also make an extremely good albeit SLIGHTLY different woofer. Who knows it could actually be BETTER suited to my application... I have no way of even knowing which would be better (no test equipment) to that specific of a degree.

Thoughts?

And PLEASE, someone... 2225 refoamed = 2235 xmax or no?

[Artcore87]

Oh I forgot... here's the recone kits i was looking at.

http://www.simplyspeakers.com/reconekits.htm
http://www.simplyspeakers.com/graphi...L-2235-Kit.jpg

[Mr. Widget]

I surely cannot afford to have JBL recone them... where can I get the real kit and how much do they cost? Given that the 70 dollar kit isn't the real deal and apparently few people here recommend them, would it be BETTER to leave it alone and just do as I said... change to foam surround and mod podge the woofer for added mass (and rigidity, more of a side benefit).

$70 isn't very much for precision parts, though I wonder about the level of precision you get for that price. If these woofers were still available they would cost ~$450 to $500 ea. The proper kits are still available and they cost over $200 each, and that includes installation by a factory trained technician. The kits are not sold to individuals.


Widget

[Allanvh5150]

The kits are not sold to individuals.

That would depend where you have friends....

Spend the dollars and get the original parts or get the job done by a JBL service tech. Well worth it in the long run.

Allan.

[HCSGuy]

Sorry boss, no luck for you.
XMax is the measurement of the woofers maximum excursion with the voice coil windings still in the saturation of the magnetic gap. It is determined by the length of the magnetic gap and of the voice coil winding. Both of these woofers share the same frame and 7.1mm magnetic gap depth. However, the 2235 voicecoil has a 19.1mm voicecoil winding length while the 2225 voicecoil winding length is only 16mm. This is where your extra XMax went.

The surround does not limit the excursion of the woofer, except on a very macro scale (like you're trying to blow the cone out of the frame, I guess). As the voicecoil starts to leave the gap, its force diminishes and movement is slowed by the spider. In worst case scenarios, the excursion is also limited by the voicecoil making contact with the bump plate of the magnet (not good either). This description is subject to revision by the experts.

Anyway, you get the point. If you want the 2235's XMax, you need the 2235's voicecoil. The 2235 is legendary - spend the extra money for a real recone. From a resale standpoint, a 2225 reconed as a 2235 is still worth about $150, while a 2225 with an aftermarket cone is worth the value of an empty frame, or about $50. This may makeup most of the premium charged for the JBL kit.

Good luck!

[ratitifb]

JBL used the 10% linearity figure for xMax in the specs above aka Linear XMax.

Mechanical Xmax (voice coil overhang) is lower - looking at the voice coil winding depth of both drivers:

2225H/J 0.63"
2235H 0.75"

And both drivers use the 0.280" top plate.

(0.63 - 0.28)/2 = 0.175" = 4.45mm
(0.75 - 0.28)/2 = 0.235" = 5.97mm

Both drivers are spec'd with the same xMech at 0.875" peak to peak (in the case of these two drivers - spider contacting top plate). Note that the bottom of the mass ring in the 2235H is in line with the bottom of the spider so both contact the pole piece and the top plate respectively at the same instant at xMech. Usually the mass ring will pop loose before the spider will.

Also note that the 2225H has a higher Bl factor meaning that it has more wire length in the gap (both drivers have the same flux density, B). This means that they use different millings for the edgewound voice coil wire (The 2225H has an Re of 6.3 ohms and Le of 1.1 mH while the 2235H has an Re of 6.0 ohms and Le of 1.2 mH).

thanks for that technical information

Do you have the same regarding 2231A basket reconed with 2235H kit

Which part/element limits first the Xmech in that case ?

[Loren42]

After much research I bought a pair of 2225H's on ebay for $250 and $40 shipping.

For what I'm using them for (home hi-fi, paired with midrange horns and a ribbon tweeter, ~5+ cu. ft. vented enclosure, tuned to 25-30hz), I would prefer to use the 2235H, and I understand that these can be reconed to 2235H's, and I've seen the kits for around $70 each. These are replacing some 15" RTR woofers (http://www.parts-express.com/pe/show...number=303-422) that are currently in the cabinets. I bought these custom made speakers which have high quality mid and HF drivers and nice custom cabinets and very nice crossovers... the cheap woofer seemed out of place. However it actually sounds pretty darn good, and can make quite a lot of bass if asked to. But, I haven't heard the JBL's yet so who knows how big the difference will be.

Buuuut actually I need these to go up to around 800hz with a 6db slope from there, so I'd like to retain some of the midbass sensitivity and transient response of the 2225H, so my question is this. I've seen re-foam kits for 2235's for 30 bucks. If I change the 2225H to a foam surround, will it be exactly the same as the 2235 EXCEPT for the difference in moving mass? And, is this difference in mass due solely to the 35g mass ring? I would like to just refoam the 2225's and put a few layers of mod podge on the cones, front and back. for added stiffness and mass. This way i could increase the mass slightly but not all the way to where the 2235 is... I'd aim for about half-way.

My fear is that the 2225 with the refoam will not have as much linear xmax as the 2235. Based on JBL's specs the 2225 only has 5mm while the 2235 has 8.5mm. So, the question is whether the difference is due to the surround or some other component difference.

Can anyone answer this question with certainty? If I don't get the 8.5mm xmax with a 2225 refoam and slightly additional mass, then I'll have to go all the way and recone them, because I want lots of clean bass.

Thanks!

I think you are way off track with your idea.

1. I don't know that the spiders are the same between the 2225 and 2235. Surely the cone mass is different. - Update: Subwoof stated that the spiders are not the same, so that would be an issue.

2. You can't just freely throw any woofer into a speaker cabinet and expect it to work based on its published frequency response or brand reputation.

3. The Thiel/Small constants will be a Frankin-driver. The modified driver's T/S constants will not be either a 2235 nor a 2225, but some unknown quantity, which is just a wild guess at this point (or gamble).

4. You are not even considering the T/S constants in this plan, so you are throwing darts in the dark while you are being spun around on a turn table trying to hit a moving target. This is completely unscientific and the chances of getting good results is about nil (there are far more things that can go wrong than right).

5. Even though the crossovers are "good ones", they will need to be redone to match the new woofers.

You are trying to cut corners. In the end, you will not be satisfied or as satisfied, and at some point you will redo the project right to get satisfied and your final expense will be much higher than what you would have spent if you had just did this right from the start.

Finally, you need to consider the whole system as a system. So driver selection depends on all the other drivers, enclosure design and alignments, and crossover. My point is that it is a holistic effort that takes a lot of work and planning. I am not confident that any of that work was done here, so the results are almost assuredly going to be disappointing.

However, I am not trying to dissuade you from building your own speaker. I just think you may be going about it all wrong and wasting a lot of time and money. I've been there myself.

[subwoof]

The spider on the pleated cones ( 04,25,40 ) are stiffer than the foam ( 03,35,45 ) models. Actually held them up and flexed them to see. Not sure how you would measure this but it is different.

Back in the day JBL would stamp-out sections of a regular spider for the 10" PR10 and I still have one somewhere but I would not suggest for anything like the 4" coil models.

sub

[grumpy]

Flip the 2225's and buy what fits your system...
or use them and possibly modify your system.

Modifying them is a good way to irrevocably piss away your $$$.

[Progneta]

I dont know if I would munk around. The 2225 is a darn good woofer. Keep her as is and enjoy! IF you want to get more xmax and bass...add a sub my .02

[Artcore87]

Thank you everyone for the comments and information. My question has now been answered =D, although it's not the answer I was hoping for!

The 2225/2235 (esp. the latter) will be a good fit for my system, which is why I chose it. I think some people here are being a BIT nit-picky though, about t/s parameters and implementation. I mean really... let's look at volume for example. Would a 2225/2235 not work well in a vented enclosure (correct port size/length for proper tuning) from 4 cubic feet thru 6 cubic feet, with 5 cubic feet or so being optimum? So... if my cabinets are 5.25 cubic feet... are you seriously suggesting my system will suck? (I know no one said they would "suck" but that's the tone of how it reads) I on the other hand think that it would be more than close enough, even CLOSE to ideal, though not perfectly ideal. I can also vary how the cabinet is damped for further tuning.

As for using an aftermarket cone kit... you MAY have persuaded me to not consider this option. The problem is money. For now I can enjoy the 2225's as is and in the future have JBL properly recone them to 2235s. The other reason for doing this is that I know JBL techs would do a better job at it than I would. However, with all the reading I've done, even though some of you clearly know quite a bit about these speakers and the principles involved, I'm not convinced that you are to be believed when you say the franken-woofer would not be good BECAUSE of the altered t/s specs.

In my opinion the determining factor for the quality of the franken-woofer would be the quality of the parts of the recone kit... that is the quality of the spider (and it being CLOSE), the quality and stiffness of the cone, surround, and quality and (CLOSE) specs of the voice coil assembly. If these parts are truly not close to JBL spec such that the t/s parameters were thrown off considerably, I would concede that they suck. However if the t/s parameters come out CLOSE, then it is a COMPLETELY EQUALLY VIABLE although different woofer. I am looking for a GOOD woofer along the lines of a 2235 but not necessarily EXACTLY a 2235. If I modpodged the cone of the 2225 to add weight and effectively reduce Fs (slightly) it would still be a GOOD woofer, just not 2225 spec... but probably BETTER for my implementation (slightly better low bass response)!

I don't really see how this is all that debatable. All of the most important aspects of the woofer that make it good would still be in place. That is, the design and quality of the parts, especially motor structure/VC/spider/cone/surround. A little added mass is really gonna make my 2225 suck? I don't think so.

Do people not use 2235's with and without the mass rings? Oops, wouldn't that throw off t/s spec considerably? Yeah of course... but jbl even makes a "franken-woofer" 2235 without the ring, the 2234. If JBL didn't sanction it, you would call it a crappy failed franken-woofer... but it's just as good, with slightly different specs.


So... although my implementation in the end may not be 100% ideal, to say it is a waste of time, money, or that it would suck I think is FAR off and rather elitist. I suspect that the drivers will mate very well, and the x-over will STILL work VERY well, and will match well (frequency and slope) with the JBL woofer. It's a simple 6db slope well within the usable range of the driver... why on earth would this NOT work well? I doubt the x-over was designed to closely match the driver in there now anyways... I wouldn't be surprised if there were nicer woofers in there before I bought them and he threw in the RTR's to save his woofers. The components of the x-over are more important than the EXACT x-over point (within 50hz).


Someone here mentioned they "knew" people at JBL... could that person get recone kits and sell them to me? Orrr could that person recone them for me? Or have them reconed at a discount? I'm convinced enough to want original true 2235h's for IDEALness' sake. But please don't diss my system 'til you hear it... or at least see some measurements! =P

I'm running a modified sureelectronics tripath TK2050 chipset board as an amplifier. The thing is SICK. Just absolutely sick.

Thank you everyone!!!! Not trying to be hostile just defending my DIY system =D. I'm planning on doing some cool horn mods I've read about too!

[Loren42]

I think some people here are being a BIT nit-picky though, about t/s parameters and implementation. I mean really... let's look at volume for example. Would a 2225/2235 not work well in a vented enclosure (correct port size/length for proper tuning) from 4 cubic feet thru 6 cubic feet, with 5 cubic feet or so being optimum?

Well, it's your money, try it and see.

Enclosure volume/tuning is only a tiny aspect of getting a system to play at its potential. I don't know what exactly you plan to use for other drivers to mate to the 15" woofer, but you are over simplifying the task by at least one order of magnitude.

Just a few things to consider, you need to consider the individual SPL levels for each driver, their frequency responses, where you choose the crossover points, type of slopes, impedances, off axis responses of each driver at the crossover points, baffle step, and a host of other factors if you want to get reasonable sound.

It is folly to take an outstanding woofer and mate it with second rate components or a poorly designed system or expect a totally different woofer to play in a different system with the existing crossover. It's also folly to take a perfectly good high end woofer and modify it without a detailed understanding of what you are doing and how all the factors impact each other.

I'm not trying to be hostile, just trying to save you money and grief with your project, but in the end it is your money and time. I've said all I need to say. Good luck.

[HCSGuy]

Artcore, I agree with your point - building a speaker is a matter of juggling many variables, and the decision to use one woofer over another often is not validated until after you've purchased, installed, and measured/listened to the woofer, often followed by re-listing it on Ebay. Other than -3db point and bass roll off, it's difficult to predict how a woofer will sound and transition to a midrange without lots of modeling with expensive software tools, usually still followed by prototyping it. I'm glad you're having fun with your project, and are willing to try anything. Personally, I've been wanting to experiment with TAD drivers, but wow! Talk about needing some serious coin - it will have to wait...

In the interest of budget, I would really consider leaving your 2225's stock while they still have resale value. If they don't turn out to be the right speaker, resell them and buy 2235's. Spending $175 reconing 2225's as 2235's leaves you with a woofer that is worth $150. I would also consider buying a cheap electronic crossover so that you can play with your woofer/mid transition - maybe a JBL M552 or equivalent on Ebay.

While it seems you have put the aftermarket kit question to rest, one final comment. When you purchase a JBL Recone kit, everything is pre-assembled for the frame you are using, so that installation is highly reliable and repeatable. Have you read the simplyspeakers kit's instructions? Holy crap! There are many extra steps to this kit, all of which are critical to performance, including "set the voice coil height according to original voice coil setting." and gluing the voicecoil to both the cone and they spider. I do not question that there are pros on this forum who have used these kits and are able to to assemble them with some uniformity, but I am not one. Even with the test equipment I have, if you had me assemble and install the kit, how many would I have to build until I got a pair that matched as well as a pre-built JBL kit? I'm guessing 5 if sober, maybe 4 if not (steadier hands). I think to assure any quality, a good professional would need to assemble and install these, and that good professional is going to charge a premium for all the extra steps needed (glue voicecoil to cone, wait at least 1hr, etc), and that extra time is going to cost money. I'd like to get one of the pro's opinion on how much extra they'd charge versus the factory kit, but I don't see how the aftermarket kit is practical. Just my 2 cents, feel free to ignore...

-John