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/showdetl.cfm?Partnumber=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/graphics_products/JBL-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/showdetl.cfm?Partnumber=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

[Artcore87]

:applaud:
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.

And I greatly appreciate the input don't get me wrong. I know there are many factors the volume was just one example of how the parameter should be close but does not need to be exact. Quality of sound is better than flatness of frequency response IMO, if for no other reason than I can EQ them flat with my 31 band Alesis EQ, but the sound character will remain the same and is thus more important.

One of the reasons I wanted these JBL's is because they have higher sensitivity than the RTR woofers in there now, which do NOT play as loudly as the midrange horns above them... and I know this is obviously not ideal! I have to EQ for this difference in output much more than I want to. The JBL woofer will match the horn level much better. Plus, I could buy a variable l-pad to put on the horn, to precisely match the levels of the 3 drivers. My speakers are in another house ATM so I can't take them apart but unfortunately I don't know what the mids and tweeters are. I realize this is slightly ridiculous. However I'm confident that they are rather good, for a couple reasons (one being how they sound). And for curiosities sake I will figure out what they are so I can know the exact specs. But the speakers were designed and built by a hi-fi enthusiast who was an engineer by trade... he had about 6 other complete systems (amps/speakers) in his home most of which costing 5 or 10 grand... this was a side project of his. So I highly doubt he made crappy speakers (apart from the rtr woofers like i said, which i suspect he put in there to sell them). He was selling most of his large gear because he was moving to a different state. He said that he specifically chose the mid and HF drivers for their specs and his previous experience with them... he said it was actually hard for him to find the tweeters he wanted and had to order them from Japan. Right now the speakers' weak point is below 1khz... the rest of the range sounds absolutely fantastic though the horn needs some EQ'ing... mainly as a level adjustment. Doing the PVC edge roll termination of the horns (maybe 120-150 degrees of the circle... whatever follows the contour) and maybe some foam or applied felt or EnABL'ing of the horns should smooth them out and reduce the need for EQ'ing. I have not heard a better tweeter.

Eventually I will build new cabs for the speakers because they COULD be better... the drivers are mounted right in the center of the baffle which is not ideal. Also I want less resonance.... its 3/4" 7-ply birch with mdf front and rear (1" up front, 3/4" rear). The vertical spacing seems good based on listening, and hoping the engineer got it right. There's also rounded wood trim that runs around the entire baffle that sticks out about 1", and I can't be sure what this is causing in terms of diffraction.

I believe the woofer low pass is 6db, horn (1" exit) high pass 6db, tweeter high pass is either 12db or 18db... I think recall him saying 3rd order, but i could be wrong... I'd have to look at it and google some values. It is a ribbon so I believe it needs the protection.... but maybe it's not a true ribbon... still need to find out.


So... can anyone recone these for me (not for free of course)... or sell me recone kits?

[Artcore87]

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

HSCGuy thank you for your input. You're probably dead-on about leaving these 2225's alone for now. I'll simply EQ for bass response and see how I like them. I couldn't find any 2235's which is why I bought them... so as for reslisting them and buying 2235's... not sure if that's doable. Plus money wise... I'd probably have to sell them first and then buy the 2235's which leaves me with no speakers for a while :'(. If the VC, and the spider, and the mass, AND the surround are all different between the 25 and the 35, then just going to foam surround on the 2225 and adding mass won't get me the extension I want (though maybe part of it)... and you're right my skills as far as refoaming them may or may not be sufficient to achieve uniformity and linearity.

As for the cone mass though... instead of modpodge (irreversible, not good for resale), what if i hot-glued some lead bb's inside at the VC/cone junction... that would be removable and unnoticeable afterwards. Could drop Fs a few hz, yes?

[Allanvh5150]

HSCGuy thank you for your input. You're probably dead-on about leaving these 2225's alone for now. I'll simply EQ for bass response and see how I like them. I couldn't find any 2235's which is why I bought them... so as for reslisting them and buying 2235's... not sure if that's doable. Plus money wise... I'd probably have to sell them first and then buy the 2235's which leaves me with no speakers for a while :'(. If the VC, and the spider, and the mass, AND the surround are all different between the 25 and the 35, then just going to foam surround on the 2225 and adding mass won't get me the extension I want (though maybe part of it)... and you're right my skills as far as refoaming them may or may not be sufficient to achieve uniformity and linearity.

As for the cone mass though... instead of modpodge (irreversible, not good for resale), what if i hot-glued some lead bb's inside at the VC/cone junction... that would be removable and unnoticeable afterwards. Could drop Fs a few hz, yes?

To be perfectly honest your are better saving up the cash to get 2235 cones dropped into your 2225 baskets. 2235 are like rockinghorse poo.

Allan.

[Artcore87]

To be perfectly honest your are better saving up the cash to get 2235 cones dropped into your 2225 baskets. 2235 are like rockinghorse poo.

Allan.


That's probably what I'll do. It would be sweet if someone here on the boards could do it or have someone they know do it at somewhat of a discount..... anyone?

[HCSGuy]

Patience, patience - 2235's come up all the time. I've passed on several on Craigslist in my area at $175-200 each over the past year. Watch Ebay and Craigslist and something will come up.

Regarding adding weight to your 2225's, add it to the edge of the dustcap, with a small gap between the weight and the glue edge. It's very easy to cut out and replace the dustcap later. I'm not sure you could get hot glued BB's off the cone without pulling the cone apart, but I'm not going to experiment.

-John

[4313B]

It would be sweet if someone here on the boards could do it or have someone they know do it at somewhat of a discount..... anyone?What would be sweet is if you'd take your drivers to a reconer, get it done and leave us out of the loop...

[grumpy]

... and here I thought -I- was grumpy... :rotfl:

[Artcore87]

What would be sweet is if you'd take your drivers to a reconer, get it done and leave us out of the loop...

generally I've always found hobbyist forums are full of exceptionally helpful, nice, and willing people, such as on the diy audio forums and many others. 4313b if that isn't you then you don't have to respond to my request. Personally if I had the connections, time, knowhow, and enjoyed working with something, I'd be more than happy to help someone out with something like this. Regarding my tripath amp thankfully there are such people out there to help in various ways, such as building custom amps and selling them for barely over parts cost.

I'll continue to search for 2235s. If anyone wants so
e 2225s at cost let me know =)

[4313B]

Whatever... :barf:

[grumpy]

I think you might be -really- surprised at how much help can be leveraged here
(albeit with a full range of experiences, that often need filtering).

I believe your original question was eventually answered in much detail
with time investment from several very experienced folks.

It -is- hard (and frustrating) to help when the helpee has painted his/her-self
into a corner and refuses the helper ... no wants to suffer that kind of query.
(ok, not many of us).

[timc]

generally I've always found hobbyist forums are full of exceptionally helpful, nice, and willing people, such as on the diy audio forums and many others. 4313b if that isn't you then you don't have to respond to my request. Personally if I had the connections, time, knowhow, and enjoyed working with something, I'd be more than happy to help someone out with something like this. Regarding my tripath amp thankfully there are such people out there to help in various ways, such as building custom amps and selling them for barely over parts cost.

I'll continue to search for 2235s. If anyone wants so
e 2225s at cost let me know =)


Perhaps....But how would you feel after xxxxxxx BS requests?


And you think $70 for a genuine JBL recone kit is expensive? Here in norway the recone kit for the 12" 2213 costs $300 EACH!

I do have a little trouble where you are going with your project. If you are planning on putting the 2225/2235 into an existing system, you will have to rework the woofer AND midsection of the crossover. That is unless you are very lucky. In wich case i would recommend buying a lottery ticket ;)


-Tim

[Loren42]

I think you might be -really- surprised at how much help can be leveraged here
(albeit with a full range of experiences, that often need filtering).

I believe your original question was eventually answered in much detail
with time investment from several very experienced folks.

It -is- hard (and frustrating) to help when the helpee has painted his/her-self
into a corner and refuses the helper ... no wants to suffer that kind of query.
(ok, not many of us).

-grumpy (was "scratchy" taken?)

+1

I agree. It is frustrating when you ask a question, get sage advice, but you already had your mind made up. You were just looking for support to do things your way (because you already bought the wrong woofers). When that didn't come you "sorta" "kinda" concede you possibly may change your mind.

Nonetheless, all of us here keep coming back to try to make your project succeed.

[Artcore87]

+1

I agree. It is frustrating when you ask a question, get sage advice, but you already had your mind made up. You were just looking for support to do things your way (because you already bought the wrong woofers). When that didn't come you "sorta" "kinda" concede you possibly may change your mind.

Nonetheless, all of us here keep coming back to try to make your project succeed.


Fair enough, I didn't mean to come across that way, so I apologize. I probably shouldn't have interpreted some others' posts the way I did which prompted my remarks. I DO appreciate the help that I have received in this thread, and never denied receiving it, so thank you all. I admit I was too impatient to wait for 2235h's to pop up, and underestimated the differences and complexity of changing a 2225 into a 2235 or something close (which I've learned may or may not be a good idea depending on the factors discussed and expressed here).

I will enjoy the 2225's for now as is, with EQ'ing. They'll be in an apartment so the bass levels achievable should be adequate for my listening level. This is certainly not going to be my last speaker project, so please understand the lack of perfectionism on my part in wanting to just get a GOOD speaker together. The next ones will be of more epic proportions, when finances allow for it.

I've been browsing for electronic crossovers and am seriously considering a Behringer DCX2496. Does anyone have any experience with or knowledge of this product and it's quality? I'm currently using an older Alesis 31 band stereo EQ also, which I may upgrade to something of higher quality, but I really haven't researched this component or how good it may be (or has the potential to be with some capacitor mods etc.). My source is my computer, which has a VIA Envy 24HT sound card (wolfson DAC 2ch 24/96 output), which has upgraded capacitors, and my music is played in Foobar, and I don't like the character of the foobar EQ, and it doesn't have enough bands, but there are some plugin EQs supposedly of higher quality that I still have to try.

I will let you know how the woofers work out in my current system with the existing crossovers. I'm a bit limited in x-over values (if i'm thinking about it correctly), because the mid horns drop off probably around 800-1khz, which is about the upper limit of the woofers... so please enlighten me as to why i'll have to modify a crossover that seems to be at the right frequency... that is, based on the lower limit of the midrange driver. The woofer should be relatively flat up to that point, no?

[1audiohack]

Disclaimer! This is not directed at anyone!!! OK;

I don't think people tinker (explore) enough, many read read read and puzzle but,,,

A 2225 is the 80's Chevy truck of the JBL line, I would be surprised if there is another 15 they made in larger quantities. I wouldn't discourage anyone from modifying either one.

So tune the box to 20Hz and see what you get, it won't be flat but what have you got to lose? Add some weight to the cone and see what you get. If you have the power and EQ what's the worst thing that could happen, pissed neighbors and or re-cone? 2225's are not in short supply.

Have some fun and see what you can learn.

Somewhere I once read, "Scientists are explorers, Engineers are pioneers, Philosophers are tourists."

You would probably not believe what I have run through a bandsaw over the years just to see whats inside. As a side note, every speaker that I have thrown in the trash since I was a kid got connected directly to the national power grid on the way out, I guess I will never grow up.

Have fun,
Barry.

[HCSGuy]

Artcore,
Here are JBL's frequency response curves for the two woofers. As you can see, the 2225 is very predictable and has a rising response between 1k and 2k. the 2235 gets really hairy after 1k. I have never built with either of these woofers (Except the 2235 as subwoofers), so I will defer to the experts, but my opinion is that the 2235 will work better with a higher slope crossover at a lower frequency (600-800hz) so that the output is pretty low by the time those lumps hit. The 2225, however, is nice and predictable up high - more friendly with different crossovers. This is the reason you see 2225's used in DIY 2 ways with 2" horn drivers, while the 2235 is more often used in 4 ways or with mids that will go lower.

I think you can also see that inserting both drivers in your existing crossover will give very different performance at the crossover point to the midrange, hence the suggestion that you will need to modify the crossover.

I don't know what your other drivers or your crossover are, but I think you might find the 2225 blends better at the top of its range. Maybe keeping your 2225's and building a sub for the first octave is a consideration?
-John

[Loren42]

Disclaimer! This is not directed at anyone!!! OK;

I don't think people tinker (explore) enough, many read read read and puzzle but,,,

A 2225 is the 80's Chevy truck of the JBL line, I would be surprised if there is another 15 they made in larger quantities. I wouldn't discourage anyone from modifying either one.

So tune the box to 20Hz and see what you get, it won't be flat but what have you got to lose? Add some weight to the cone and see what you get. If you have the power and EQ what's the worst thing that could happen, pissed neighbors and or re-cone? 2225's are not in short supply.

Have some fun and see what you can learn.

Somewhere I once read, "Scientists are explorers, Engineers are pioneers, Philosophers are tourists."

You would probably not believe what I have run through a bandsaw over the years just to see whats inside. As a side note, every speaker that I have thrown in the trash since I was a kid got connected directly to the national power grid on the way out, I guess I will never grow up.

Have fun,
Barry.

I don't have a problem with experimentation, but you have to be careful with what you do.

For instance, tuning the box to 20 Hz is a bad idea. It is a common mistake for the uninitiated to do this, but it can have devastating consequences as shown below:

http://www.mdbq.net/audio/2225box2.jpg

The red trace is the 2225H in the recommended vented enclosure (5 cubic foot) tuned to 30 Hz. The yellow trace is the same enclosure tuned to 20 Hz.

While it looks like you have extended the bass lower on the frequency plot, look at the cone displacement plot. Normally, xmax is reached at 26 Hz, but the cabinet tuned to 20 Hz exceeds xmax in two places, the first being at about 43 Hz, then again below 20 Hz. This is a good way to destroy a speaker that does not have a large xmax like the 2225.

The other experiment of adding mass to the cone is the green plot. I never really tried this except in theory, so I don't know what will really happen if you do this.

I added the 35 gram mass ring from the 2235H plus 15 grams of glue to approximate the mass of the 2235H cone. The result drops the Fs to about 26 Hz. Again the xmax is going to be close for this driver and you need a steep low cutoff at 26 Hz or higher to prevent over excursion.

Again, this is a theoretical experiment and the actual acoustic profile will most likely have gremlins that may not be desirable. The only way to determine that is to measure the speaker, which requires tools.

In reality, the xmax problems will not be a big problem unless you crank up the bass to compensate for the loss of bass. The yellow trace has a pretty steep rolloff and trying to compensate by assisting the rolloff with a bass boost goes badly wrong because the 2225H does not have sufficient xmax. You risk, at minimum, a lot of distortion, and at worst, voice coil damage.

[Artcore87]

Artcore,
Here are JBL's frequency response curves for the two woofers. As you can see, the 2225 is very predictable and has a rising response between 1k and 2k. the 2235 gets really hairy after 1k. I have never built with either of these woofers (Except the 2235 as subwoofers), so I will defer to the experts, but my opinion is that the 2235 will work better with a higher slope crossover at a lower frequency (600-800hz) so that the output is pretty low by the time those lumps hit. The 2225, however, is nice and predictable up high - more friendly with different crossovers. This is the reason you see 2225's used in DIY 2 ways with 2" horn drivers, while the 2235 is more often used in 4 ways or with mids that will go lower.

I think you can also see that inserting both drivers in your existing crossover will give very different performance at the crossover point to the midrange, hence the suggestion that you will need to modify the crossover.

I don't know what your other drivers or your crossover are, but I think you might find the 2225 blends better at the top of its range. Maybe keeping your 2225's and building a sub for the first octave is a consideration?
-John

HSCGuy, and Loren42, thank you very much for the hard data and insights, this is exactly the kind of helpful stuff I was looking for! I'm feeling better about the 2225's for a couple reasons, one being the better performance in it's upper ranges, since my midrange horn doesn't go all that low without sounding like a horn (below 1khz for sure). I'm also going to experiment with putting felt on the walls of the horn and modifying the mouth termination with sections of pvc covered in felt also to round off the termination, and also as a side benefit should get the end of the mouth out as far as the 1" wooden border around the baffle, to reduce it's diffraction effects I hope/think in theory. I may remove that border altogether... it just wouldn't look as pretty. In addition I will somehow damp the the horns internally (I've heard about some people using putty?) because there is some ringing during a sine sweep of moderate volume, which is not very noticeable with music, but obviously it's having some effect.
I will tune the box to 30hz as suggested, and it's gonna get some additional internal reinforcement (I believe there's enough displacement that lowering it might actually help... I have yet to measure to be sure though.)

Would anyone recommend or NOT recommend putting a variable l-pad (forgive me if they are ALL variable...) on the midrange? Does this degrade the signal significantly?

I only hope that I find the 2225's to be loud enough down to 30hz (not really worried about frequencies below that, no pipe organ music here... though I do listen to some electronic music with very low frequencies). A 30hz F3 would be awesome, 35hz would be good enough.

[Loren42]

Would anyone recommend or NOT recommend putting a variable l-pad (forgive me if they are ALL variable...) on the midrange? Does this degrade the signal significantly?

I only hope that I find the 2225's to be loud enough down to 30hz (not really worried about frequencies below that, no pipe organ music here... though I do listen to some electronic music with very low frequencies). A 30hz F3 would be awesome, 35hz would be good enough.

I use an L-Pad to set the level, then replace the L-Pad with resistors once you figure out the actual level you need.

Looking at the red trace you are 9 dB down at 30 Hz. In reality you will be another 3 dB (or more) down due to diffraction losses on the front baffle.

Looking at the numerical data on the plots I gave you shows F3 for the red trace at 97.7 Hz. That isn't anywhere near where you want it and the only way you can get close is with a 2235H.

I have a plot that shows an F3 of 36 Hz with a 2235H in a 5 cubic foot box tuned to 30 Hz. The 2235H likes more volume and my box has 6.7 cubic feet with an F3 of 32 Hz when tuned to 30 Hz.

No way will the 2225 get you what you want without a sub.

[Artcore87]

I use an L-Pad to set the level, then replace the L-Pad with resistors once you figure out the actual level you need.

Looking at the red trace you are 9 dB down at 30 Hz. In reality you will be another 3 dB (or more) down due to diffraction losses on the front baffle.

Looking at the numerical data on the plots I gave you shows F3 for the red trace at 97.7 Hz. That isn't anywhere near where you want it and the only way you can get close is with a 2235H.

I have a plot that shows an F3 of 36 Hz with a 2235H in a 5 cubic foot box tuned to 30 Hz. The 2235H likes more volume and my box has 6.7 cubic feet with an F3 of 32 Hz when tuned to 30 Hz.

No way will the 2225 get you what you want without a sub.

Well, I'm interested in that xmax graph because I only expect it to extend that low after I EQ it... I'm sorry I forgot to mention that and make it clear. I would like an F3 of 30-35hz after equalization, and I will drop the 16hz band (and maybe one above it) to prevent over-excursion below that... and when they are operating in that respect the only question then is how loud they'll be able to do that, and I'm hoping that it is loud enough. If not, 2235h's will be in my future, or a proper reconing. It seems odd to think that these 400w woofers cannot produce low bass as loudly as the cheap RTR 15"s that are in there now. Even they seem to have more xmax than the 2225... but maybe not, perhaps when I push them hard they're simply operating out of (semi) linear xmax range between that and xmech... but still they can go loud and clean, and at least have low distortion with single note bass notes and (with) or bass drum hits. If they sound that clean out of xmax then maybe pushing them won't sound too bad... they have the same xmech as the 2235h's. The only reason I would do that is for the those occasions when I simply want a healthy dose of bass, sometimes I am a bass fiend. Normally I'd keep them well within very-low-distortion limits for 90% of listening.


Buuut I think you're right... eventually I'm going to need 2235's for the real performance I want. This will just have to do for now! Thanks again.

[grumpy]

Last on this from me...

I'd recommend you cut wood and get a feel for how the 2225 will work
in your system (I'd further recommend a higher box tuning... more like
40Hz... should be nice and punchy, but do as you will).

Room gain will help -some- on the low end, but don't expect miracles.

Also, don't be surprised if the smoothness shown on old sales sheets
is not really comparable between decades of product... (2225 vs 2235...
it -appears that the 2225 curve is more a plot of the spec, -derived- from
data, where the 2235 plot actually represents a measured driver... having
measured one or two myself).

Get your system out there, show what you're assembling, ... have some
fun.

Later.

[Loren42]

Last on this from me...

I'd recommend you cut wood and get a feel for how the 2225 will work
in your system (I'd further recommend a higher box tuning... more like
40Hz... should be nice and punchy, but do as you will).

Room gain will help -some- on the low end, but don't expect miracles.

Also, don't be surprised if the smoothness shown on old sales sheets
is not really comparable between decades of product... (2225 vs 2235...
it -appears that the 2225 curve is more a plot of the spec, -derived- from
data, where the 2235 plot actually represents a measured driver... having
measured one or two myself).

Get your system out there, show what you're assembling, ... have some
fun.

Later.

I agree! Just keep expectations realistic and have some fun learning.

As Grumpy said, retune your cabinet to 40 Hz. I would also bump the internal volume up to 6 cubic feet (you can always make it smaller and it will allow an upgrade path for the 2235H).

Here is a comparison with the old 30 Hz tuned box 5 cubic feet (red trace) and a 6 cubic foot box tuned to 40 Hz (yellow trace).

You will have a much better sounding bottom end with the 40 Hz tuning.

http://www.mdbq.net/audio/2225Box3.jpg

[Artcore87]

I agree! Just keep expectations realistic and have some fun learning.

As Grumpy said, retune your cabinet to 40 Hz. I would also bump the internal volume up to 6 cubic feet (you can always make it smaller and it will allow an upgrade path for the 2235H).

Here is a comparison with the old 30 Hz tuned box 5 cubic feet (red trace) and a 6 cubic foot box tuned to 40 Hz (yellow trace).

You will have a much better sounding bottom end with the 40 Hz tuning.

http://www.mdbq.net/audio/2225Box3.jpg

Hmm, you're right. The yellow trace has better performance to 35hz, which is my goal... I'll then use EQ to cut the ultra low frequencies to stay within xmax. Thanks. I'll have pictures and more info as I gather it.

[Artcore87]

I agree! Just keep expectations realistic and have some fun learning.

As Grumpy said, retune your cabinet to 40 Hz. I would also bump the internal volume up to 6 cubic feet (you can always make it smaller and it will allow an upgrade path for the 2235H).

Here is a comparison with the old 30 Hz tuned box 5 cubic feet (red trace) and a 6 cubic foot box tuned to 40 Hz (yellow trace).

You will have a much better sounding bottom end with the 40 Hz tuning.


Loren42 would you be so kind as to run that program with a box volume of 4.6 cubic feet? It turns out this is the volume of my cabinets... and minus the horns internal volume and the drivers own displacement it's even somewhat smaller than that, you may be better able to approximate the difference... i would say no less than 4 cu. ft, maybe up to 4.2 cu. ft.

Currently it has one port that is 4.5" x 6.5", so please model that as well.

And, again, if you would so generously be able to find the optimum tuning for a box of this size (and optimum port dimensions), I would be most grateful.

Also, the port is in the rear... how would this act differently than if the port was in front? They'll see time both corner loaded, and simply back-loaded (one wall), in not-so-large rooms.

[Loren42]

Loren42 would you be so kind as to run that program with a box volume of 4.6 cubic feet? It turns out this is the volume of my cabinets... and minus the horns internal volume and the drivers own displacement it's even somewhat smaller than that, you may be better able to approximate the difference... i would say no less than 4 cu. ft, maybe up to 4.2 cu. ft.

Currently it has one port that is 4.5" x 6.5", so please model that as well.

And, again, if you would so generously be able to find the optimum tuning for a box of this size (and optimum port dimensions), I would be most grateful.

Also, the port is in the rear... how would this act differently than if the port was in front? They'll see time both corner loaded, and simply back-loaded (one wall), in not-so-large rooms.

This is what I get for 4.2 cubic feet. I think you would be happier with the results if you could get the internal volume up to 6 cubic feet, but if you must use this volume, here are the details, which is not that bad:

http://www.mdbq.net/audio/2225box5.jpg

The rectangular vent is fine. The maximum air speed is 12 m/s, which is quite acceptable. For comparison and contrast, making the box 6 cubic feet yields the following:

http://www.mdbq.net/audio/2225box4.jpg

The yellow trace is the 2225H. The orange trace is a 2235H. All you need to do in this case is change port length to retune the box lower and drop in the 2235Hs. Notice the F3 on the 2235H. Six cubic feet gives you the option to change drivers without making major changes to the box. All you need to do is change the port length, which in this design is two 4" diameter vents.

What I have given you is only the first cornerstone of the design. There is a lot more work to do to complete a design. Vance Dickason's The Loudspeaker Design Cookbook would go a long way toward completing the design.

As far as a rear firing port goes, I don't think it makes a big difference, but perhaps someone else here might speak up about that?

[Artcore87]

This is what I get for 4.2 cubic feet. I think you would be happier with the results if you could get the internal volume up to 6 cubic feet, but if you must use this volume, here are the details, which is not that bad:



The rectangular vent is fine. The maximum air speed is 12 m/s, which is quite acceptable. For comparison and contrast, making the box 6 cubic feet yields the following:



The yellow trace is the 2225H. The orange trace is a 2235H. All you need to do in this case is change port length to retune the box lower and drop in the 2235Hs. Notice the F3 on the 2235H. Six cubic feet gives you the option to change drivers without making major changes to the box. All you need to do is change the port length, which in this design is two 4" diameter vents.

What I have given you is only the first cornerstone of the design. There is a lot more work to do to complete a design. Vance Dickason's The Loudspeaker Design Cookbook would go a long way toward completing the design.

As far as a rear firing port goes, I don't think it makes a big difference, but perhaps someone else here might speak up about that?

Thank you, but I have to apologize I was not clear about the port... it is 4.5" diameter, 6.5" long.... any chance you could re-model with that spec? And I will read the suggested material.

[1audiohack]

I have years ago beat the 2225 thing to death in my home trying to make them something they are not. I hope you don't think I would intentionally lead anyone astray, sometimes it seems you've just got to hear the differences yourself before you concede the fact that forcing a driver into a duty it was not designed for is folly.

Anyway you said the RTR's play clean and loud right? I would continue the path your now on with the 2225's and make a box for the RTR's and use them for subs.

It's very gracious of Loren42 to run sims for you!

All the best.

[Loren42]

Thank you, but I have to apologize I was not clear about the port... it is 4.5" diameter, 6.5" long.... any chance you could re-model with that spec? And I will read the suggested material.

If you look at the gray box on the left of my plots, under Box Properties you will see a term Lv = 6.174". That is the length of the port. The heigh and width are 4.5" by 6.5".

Your 4.5" diameter round port is too small. I would suggest two 4" ports or go with one 6" inside diameter port.

If you want a flush mount tubular vent, just calculate the length as follows:

Lv = [ (1.463 * 10^7 * R^2) / (Fb^2 * Vb) ] - 1.463 * R

Lv = port length in inches
fb = Desired tuning frequency
Vb = box volume in cubic inches
R = radius of port in inches

The minimum port area in your case works out to a minimum of 25 square inches. Two 4" diameter ports have an inside area of 12.57" each. Just double that number and calculate the value of R using PI*R^2 = A (it works out to a diameter of about 5.768". Calculate R by 5.768"/2 = 2.884"). Use that calculated value of R (2.884") for calculating the length of two 4" ports. Make sense?

[Artcore87]

If you look at the gray box on the left of my plots, under Box Properties you will see a term Lv = 6.174". That is the length of the port. The heigh and width are 4.5" by 6.5".

Your 4.5" diameter round port is too small. I would suggest two 4" ports or go with one 6" inside diameter port.

If you want a flush mount tubular vent, just calculate the length as follows:

Lv = [ (1.463 * 10^7 * R^2) / (Fb^2 * Vb) ] - 1.463 * R

Lv = port length in inches
fb = Desired tuning frequency
Vb = box volume in cubic inches
R = radius of port in inches

The minimum port area in your case works out to a minimum of 25 square inches. Two 4" diameter ports have an inside area of 12.57" each. Just double that number and calculate the value of R using PI*R^2 = A (it works out to a diameter of about 5.768". Calculate R by 5.768"/2 = 2.884"). Use that calculated value of R (2.884") for calculating the length of two 4" ports. Make sense?

It does make sense, thank you very much. Since the cabinets already have the one 4.5" circular hole cut in them I will simply go with a single 5 7/8" port.

And 1audiohack, I can't BELIEVE I didn't think of that myself!!! I was planning on selling them and some other drivers I have to a friend as a first speaker build project on a budget. The RTR drivers don't have the upper bass/low midrange detail that I want that the 2225's should provide, but as subs for under 40-50hz they should perform just fine... with 2 15"s at normal listening levels they shouldn't have to move too much and should thus be very accurate. I'll power them with another 45w (thats a CLEAN <.01% thd 45 watts) tk2050 tripath amp like I have driving the mains. These woofers have much tighter bass with this amp than any other I've tried (several decent mid-fi receivers and a vintage onkyo). If I get a behringer electronic crossover I will buy 2 lower power tripath amps for the tweeters and horns, for a total of four amps.

If I decide to go the subwoofer route... would it be better to tune the 2225's higher than originally planned (40hz) for optimum performance in their range? And secondly what should that range be... I could x-over as low as 40hz to the subs... but would 50hz be better, with a higher main cabinet tuning? I'd like to keep the accuracy and detail of the 2225's as low in the range as I can. Also, in this case should I high-pass the 2225's? Or would adding additional x-over components compromise sound quality too much? If I leave the mains passively crossed, how should I cross between them and the subs? Another passive with a high pass and low pass between 40-50hz, 12db/oct... steeper? Or would I simply split the full signal from the point of my graphic EQ and send the full signal to the mains and the subs, with a passive x-over in the subs? Or would this screw up impedance matching at the amplifier input?

Unfortunately there is no info online (that I've been able to find) about these RTR drivers, so I don't know where to start as far as building a cabinet... except for guessing of course. I don't have the necessary equipment to figure out their specs. They were always sold in vented enclosures, so I'll assume it's best I go with vented and that they would not work well sealed... good assumption? I'll give them each their own box and run stereo... use them as speaker stands (and flip my speakers vertically so the horns/tweeters stay at ear level, with the 2225's on top). I'd like to tune them to 25hz. I wouldn't tune them lower than that because I doubt these woofers would really operate well THAT low, since they're not subs or extreme woofers in the least. I mean they're not bad, decent sized magnet assembly... a lot bigger than the magnets on my KLH 15"s which I also still have... bigger spider as well, and it looks like a slightly larger voice coil. How would I approximate a good box volume without knowing the driver specs?

[Loren42]

How would I approximate a good box volume without knowing the driver specs?

Get Vance's book. He explains exactly how to determine the driver's Theil/Small constants empirically so you can design the best enclosure. You don't need as much equipment as you think.

[clubman]

I have a pair of 2225's in a large box(cant remember cubic feet) tuned to 40hz and love the sound they have. They are used as HT mains

[Artcore87]

I have a pair of 2225's in a large box(cant remember cubic feet) tuned to 40hz and love the sound they have. They are used as HT mains

Glad to hear it. The woofers arrive today so preliminary listening will begin shortly.

[Artcore87]

Glad to hear it. The woofers arrive today so preliminary listening will begin shortly.

Ok so I've been listening to the new woofers for a while, in a couple different diy treated listening environments and I must say I'm quite impressed. While I'd love to have the 2235's for those times I really want to blast it and want loads of bass, the 2225's are definitely adequate and don't require subs at all. EQ'd, at my listening levels (moderately loud), I'm getting flat output to about 30hz, and the usable output extends at least to 25hz, if not 20hz... as evidenced by some dub step and psytrance I have. This is corner loaded with some sound absorption behind the speakers and in the other corners, and a carpeted floor in a room about 15x17, with a large opening in 2 of the walls (could have better pressure loading at ultra-low freqs. if it wasn't for this room design).

The vocal range handled primarily by the woofers (<1000hz) sounds gorgeous and extremely detailed compared to previous woofers. Before voices sounded very disproportionately detailed... the upper range covered by the mids was very detailed while the lower part was muddy and nonlinear. Now it sounds like one coherent voice.

Particularly in electronic music the increase in bass detail and linearity compared to the RTR's is huge. The detail in bass now approaches that of the horns and ribbons above it... differently shaped LF/ULF synth effects actually sound detailed and unique rather than boomy and muddy or mostly sounding like sine-waves. Sub-sonics (15-25hz) are actually sensed, and as long as I keep them within xmax no amount of signal layering found in most music can seem to smear the detail of these woofers. Drum and bass hits don't lessen the detail in a present voice as they did with the RTR's. In this respect, I may in fact be more pleased than if I had the 2235's. The punch and articulation of these woofers is exceptional even down into the 20's. My slightly too small cabinets are working very well I suspect due to the large amount of internal damping material (all walls except front baffle). I still have to increase the port size to 6" and based on listening/intuition I believe this will have a positive effect of even more linear bass and slightly lower flat extension. Since the larger port should reduce cabinet pressures, theoretically the unwanted sound they put off should be reduced, as well as a reduction in ULF energy absorption.

I haven't made any changes to the crossover and the speakers sound much more integrated and flat than they did before with the RTR's (perhaps indicative of them not being designed around those woofers). Albeit with some EQ (only mild at the woofer/mid x-over point) the whole system blends seamlessly. EQ is mainly used to boost ULF and UHF (the JVC ribbon tweeters aren't as sensitive as the AKAI compression driver/horn combo... yes I looked at the models!) No L-pad will be needed.

[Artcore87]

I just purchased this amplifier, as I had shorted out my Sure tripath tk2050 (tc2000 + 2x tp2050) chipset amp, which is a great amp and an unbelievable value (just replace input caps and output coils and you get an extremely hi-fi amp), it was good for about 40 super clean (.01% thd) watts, but thd went up quickly from there hitting 10% by 60 or 65 watts. This one will be good for about 50w (@ .01%), 60w (@ .02%), 130w (@ .1%). This will correct a specific weakness over the Sure amp with material that has a high dynamic range, with peak transients that would push the Sure into very high THD (>10%) levels for brief moments, which would definitely be audible. This obviously is only a problem @ rather high average output levels. My avg. (or what I want possible) listening level ranges from 95 to 100 db, with 115db peaks. So, with 98db efficient woofers and probably (guess) 104-108db efficient horns, and less efficient super tweeters above that... so maybe an average efficiency of 98-100db/w/m when EQ'd, including crossover components.

So, about 40w (@.1% thd) would get me 110-112db peaks at listening position, while 130w (@.1%) will get me 115-118. A worthwhile upgrade IMO.

The Sure is a great amp if 35-40w is enough for you. If I ever run bi or tri-amped i'll probably use 1 or 2 of the Sure amps for the midrange/tweeter, since it would have plenty of power for that use. I could then use the connex amp on the woofers and have 110w just for them :D! This amp is gonna make me want the 2235's I know it.

[Russellc]

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.

I would contact them quickly, before they are moved to china and JBL quits making them. Then you better know someone with a time machine.
Its a little over 400 a pair and worth every penny. Do it while you still can! Time is growing short.

Russellc

[Russellc]

Glad to hear it. The woofers arrive today so preliminary listening will begin shortly.


Yes, 30 hz is too low for these drivers. In 5 cu ft (4505/4647 box) tuned to 40 hz, they slam like crazy, with insane rimshots. Just not as low as 2235H, but lower than my A7's ever dreamed of.

russellc

[Russellc]

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.

How do you figure? the recone for the driver will be over 200.00. I'll take all you have of the 2225H at 50 bucks, as well as your reconed 2225h to 2235H for 150.00. How big a truck should I bring?:D:D:D

Russellc