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Thread: "hybrid" reconed drivers: Sound & t/s para. Issues: Any available info ?

  1. #1
    Senior Member RMC's Avatar
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    "hybrid" reconed drivers: Sound & t/s para. Issues: Any available info ?



    Many drivers out there had to be reconed (or re-foamed) with different recone kit (or re-foam kit) than the original stuff, for reasons of availability, cost, etc. I don't recall seeing something written on this matter with some science, like actual measurements done, or experience in the field described after job done, and comparison with the original's sound and/or specs, particularly T/S parameters. It would be interesting to know what fellow members have to say about this in terms of sound and/or measured specs. Some measurements are relatively simple, like Re Voice coil resistance or Fs Free air driver resonance, while others are more complicated to do. Big sound difference ? Large deviations in specs ? Please jump in and let me know your comments or experiences.

    Here's a specific example (many others possible) from another thread with regards to a JBL driver:

    Out of curiosity, why 2225H (recones) on E-140 frames for the 4520 ? Why not E-140 recones ? Or 2225H recones on 2225 frames ? Only thing available/on hand ? Cheapest solution (money, ya that bugger)? For the longer cone travel of 2225 (5mm) VS E-140 (3.56mm)? For the smaller .17 Qts of the E-140 (closer to 2205 Qts of .21) compared to 2225's .28 Qts ? Since there's a lot of other "hybrids" out there (e.g. 2205 reconed with 2225), I have always wondered what happens in these cases to driver specs T/S parameters, a mix of both ? And how does the driver reacts in the box: acoustically like a 2225H but electrically like a E-140 ? A mix of both ?

    Richard

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    Senior Member Ed Zeppeli's Avatar
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    JBL used the same frame/basket to make multiple speakers; the qualities of which were determined by the cone characteristics. 2234, 2235, 2205, 2225 are interchangeable, for example.

    Or are you talking about aftermarket kits?

    http://www.audioheritage.org/vbullet...ight=mackenzie
    DIY Array, 2242 sub, 4408, 4208, Control 8SR, E120 Guitar cab, Control 1, LSR305.

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    Senior Member RMC's Avatar
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    Thanks Ed for your reply and the 2011 thread I didn't have. Both very interesting. I was talking about BOTH possibilities (OEM recone on different frame/basket and aftermarket recone on same basket), with potential results available in terms of sound and/or T/S parameters actual experience members had.

    As for the same frame/basket used by JBL for many drivers and qualities determined by the cone's characteristics, I note as an example in your list 2205/2225 as being interchangeable, but if you remember some of the parameters of the two are quite different, in the following order 2205/2225:
    Fs 30/40HZ ; Qts .21/.28; Vas 297.3/170 liters; X max is also different. These differences are substantial here. So after a recone job will that 2205 now be considered for all practical purposes a 2225 ? The impact on driver suitability for a particular box could then switch from go to no go...

    The example I gave about 2225 recones on E-140 frame was a question I asked EAULIVE (I just noticed he's in the 2011 thread) in a recent thread about 4520 cabinets but he didn't provide a reply on that issue. Since I MAY have to do some work on my JBL drivers in the near future I'm interested in knowing...

    Richard

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    Senior Member Ed Zeppeli's Avatar
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    Quote Originally Posted by RMC View Post

    As for the same frame/basket used by JBL for many drivers and qualities determined by the cone's characteristics, I note as an example in your list 2205/2225 as being interchangeable, but if you remember some of the parameters of the two are quite different, in the following order 2205/2225:
    Fs 30/40HZ ; Qts .21/.28; Vas 297.3/170 liters; X max is also different. These differences are substantial here. So after a recone job will that 2205 now be considered for all practical purposes a 2225 ? The impact on driver suitability for a particular box could then switch from go to no go...
    Do you not feel that these differences could be explained by the cone alone?

    I'm not an expert here, but I do know that after extensive research here I reconed some 2205s (not 2205A) as 2235Hs successfully using OEM kits.
    DIY Array, 2242 sub, 4408, 4208, Control 8SR, E120 Guitar cab, Control 1, LSR305.

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    Senior Member Eaulive's Avatar
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    I invite you to this read:http://www.lansingheritage.org/html/...s/tech1-3a.htm
    You should be able to make up your own mind about mixing cone kits and frames ;-)
    My avatar: 4520 loaded with 2225H on E140 frames,
    1x B&C 12PE32 on custom front loaded horn, 2x 2426 on 2370.

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    Senior Member RMC's Avatar
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    ED I do not know for sure yet (not yet convinced) if the differences could be explained by the cone alone. That's why I'm seeking input from other members who have gone through the process, and maybe took some measurements of the results. Perhaps of more importance to me here is the fact YOU did reconed 2205 to 2235H successfully using OEM kits. I'm relying (with no doubt) on your ear to say this was a success. That's helpful.

    What about some numbers others MAY have measured ? Other experiences good or bad and why ?

    EAULIVE did reply today re 2225 recones on E-140 frames in the other thread I had on 4520 cabinets. I hereby transfer his interesting reply in this thread:

    "Originally I was planning on loading the cabs with 2225s but since I had a bunch of E140 frames on hand I checked the possibility and tried to predict the behaviour of the E-140/2225 mix.
    Both frames have the same gap width and length, the only difference lies in the magnet strength. The 2225 has a 1.2T motor while the E-140 has a 1.35T motor so I figure after much reading here and elsewhere that the only difference would be in higher frequency response outside the band I was planning to use them (my 4520s are crossed at 150Hz with my midbass horn) so I went with that.
    Besides, I don't like the aluminum dust cap on a speaker system that is intended to be a sound "reproducer", not a sound "producer"

    A friend had original 2225s so we swapped them for fun and did not see a difference for that specific application (4520s crossed at 150Hz)

    As for the other "mixes" a 2225 on a 2205 frame is basically a 2225 because the frame and magnet structures are identical, the big NO-NO is using these cones on a 2220 frame as I saw in the past... Lee will remember the source of my 4520s and the drivers the guy wanted to push on us ;-) "

    I thank both of you for the "food for thought". I'm still chewing on that. I will read again JBL's Tech note # 1-3A which I had and looked at a longggg time ago.

    Don't hesitate to come back.

    Richard

  7. #7
    Senior Member Flodstroem's Avatar
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    Data tells me that the "woofer" is not getting to be as the original (2225):
    Both frames have the same gap width and length, the only difference lies in the magnet strength. The 2225 has a 1.2T motor while the E-140 has a 1.35T motor so I figure after much reading here and elsewhere that the only difference would be in higher frequency response outside the band I was planning to use them (my 4520s are crossed at 150Hz with my midbass horn) so I went with that.
    You/he has described some of the baskets as heaving the same dimensions BUT different magnetic strength. In the next setting it says the only difference would be in the higher frequency response outside the band (in use). It couldnt be that because the Bl-product is different. That means the voice coil built for a 1.2T is now going to work in a different magnetic strength. The Bl product is changed for that 2225 woofer with a factor of approx 1.125. It means the Tiele/Small parameters has change in the whole frequency band, not only in HF. For example, Fs has risen and that means a lot. You can not put a voice coil in a stronger magnetic motor and then say it is the same woofer in the LF band. Its easy to see that for example in a bass box simulation program. Thats my experience so far.
    Flodstroem

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    Senior Member RMC's Avatar
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    Hi to my Norwegian friends ! I worked for Norway's Kvaerner for many years in Canada...

    Apart from that, I'm really glad you jumped in and shared your data experience with us. This is exactly the type of responses I'm looking for, in addition to driver perceived sound/reaction in a box after having done a recone job. I'm still searching on my side to find additionnal examples, and I will come back shortly with more info as it becomes available. All other recone/refoam examples are also welcomed, good or bad result , I don't care as long as we try to explain them to avoid other members a deception in reconing/refoaming driver X with recone kit Y ... Thanks again my friend !

    Richard

  9. #9
    Senior Member Flodstroem's Avatar
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    Quote Originally Posted by RMC View Post
    Hi to my Norwegian friends ! I worked for Norway's Kvaerner for many years in Canada... Richard
    Thanks for your kind words Richard. In fact, I have Kvaerner-Stord, 10 minutes on the other side of our fjord here in Hardanger where I live

    Regarding re-coning issues and to mix up different cone kits with not original baskets/magnet motors I would like to come back with an example
    simulation later......
    Flodstroem

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    Senior Member RMC's Avatar
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    Hi Flodstroem,

    I'm glad you have an example simulation for us, this is part of the real life stuff I like. On my side I have found some interesting thing, which appears to CONFIRM your argument about frequency response not being the same when reconing to a different frame/basket. I will also be back with this info later. Thanks again,

    Richard

  11. #11
    Senior Member RMC's Avatar
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    Some findings about hybrid recones



    In the Thread link given to us here (Post # 2) by Ed Zepelli here are some quality related references :

    Edgewound (Authorized JBL Pro reconer), Post # 69 "A D120F "kit" is no longer made because the kit to repair a D120F is the E120 recone kit which brings the model up to improved, latest specs."

    Edgewound, post # 79 "... have reconed many D120Fs with the E-120 kit. The end result is a K-120." K(alnico) or E(ferrite) 120 ?? Also T/S parameters differences between the two driver versions (K/E-120). Regardless, still different than a D120F...

    Ivica, Post # 123 "with JBL 2202 ( C8R2202 ) and MacKenzie 2202 kits applied to the same basket. It can be easily visible that at over 2kHz they have quite different behaviors." See link posted here for result details.

    Ivica, Post # 136 "If talking about JBL 2202 recone, I have to confirm that their kit is fare, fare, fare ...,away from JBL , looking at tha cone, and the measurements confirm that."

    1Audiohack, Post # 154 "...most of the failures I see with non JBL kits are 10-15 rounds of the bottom of the voice coil loose and in the bottom of the motor."

    Robh3606, Post # 5 in underlined link above, says " I have done my own aftermarket measurements and had similar results to the ones posted. I see it as reason to stay away from the aftermarket kits if only because you don't know what you are getting. "

    In same long Thread link from Ed, those who indicated having done a recone job with Aftermarket recone kit appear to be satisfied with sound, considering the price paid (except for Ivica re 2202):

    Ian, # 138 "I mean foam rot is a much easier fix and the surround has much less impact on the T/L than the spider." T/L or T/S ? If Thiele/small, lets not forget that Vas parameter is directly linked to the Surround.

    VSN, Post # 47 "looks and sounds just like a JBL to me."

    Ear for Life, Post # 129: "I tried the Mackenzie 2226H recone kit last year. All I can say is that they delivers the performance!!"

    Lee, Post#147 "My McKenzie recones are 5 years old and still keep on pumping some great bass. ;-)
    BTW I have some 2226 Mckenzie recones and for 25% the price of the JBL unit, I get 95% of the quality."

    Naturally, these last three are subjective, not scientific evaluations, but still worth mentioning. However, It looks like to the trained eye, differences with Aftermarket recone built quality compared to OEM can be seen or measured.

    I also noted that when a member (Eaulive Post # 46; Lee Post # 115) disputes same voice coil for 2225 and E-140 to an Aftermarket recone Company or when the member requests new T/S specs with their cone installed then the Aftermarket recone Co. becomes silent... Generic type answers yes, but hot questions seemed to be tossed under the carpet.

    I don't blame people looking for aftermarket recone kits, specially when the OEM kit is no longer available or if it sells for big money compared to driver price paid... I guess an Aftermaket kit is better than a non-working driver... OEM remains an ideal choice a few persons have mentioned and have gone that way.

    The question I'm more interested in here is wether the specs (T/S) remain the same (or at least close) or not after a recone job is done with kit X (OEM or AF) into a different frame/basket, or with AF in same frame/basket . I have yet seen only one member reporting actual measured differences post-recone (Ivica, Post # 123 above, OEM VS Aftermarket, in another frame/basket). As reported by Ivica: "mine E120 basket "re-coned" with McKenzie 2202H kit " and " ... I have got JBL 2202H recone kit (C8R2202) and 'put it' into E120 basket." His frequency response curves on same graph do show differences, not only with Barry's original 2202H, but also among the two recone jobs (OEM vs Aftermarket). Ivica, Post # 10 in underlined Thread link above.

    Moreover, installing a 2225 recone on a E-140 frame/basket for example would not lead to specs being as an original 2225, even at low frequencies, according to fellow member FLODSTROEM's report based on a simulation done with speaker software. Very clever ! In addition, well-informed member 4313B reports (Post # 11), in the Thread link underlined above (re Ivica, Post # 123), "An E120 core is going to generate higher Bl than the 2202A, K120, 2203A, 2203H, 124A, 124H or 2202H cores due to its increased flux density." This would seem to confirm Flodstroem's statement here about BL product impact on driver response. We'll see in his upcoming software simulation.

    Richard

  12. #12
    Senior Member edgewound's Avatar
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    There's an awful lot to discuss here, but the clear point is this:

    When installing a particular model of recone kit in a core that is identical to another model, the speaker becomes the recone kit model in which it's intended. A 2235H kit installed in a 2225H/J core becomes a 2235H. An E-130/140 core with a 2235H kit installed is not a 2235H equivalent due to the stonger motor. The frequency response is shifted upward. An E120/E130/E140 kit installed in a D-Series core gives a net result of a K-Series driver.

    The biggest violation of JBL core recones is the 130A/2220, LE-15 and K/E145. No other JBL cone assembly can be installed in these cores and be expected to work properly...key word being properly, even though the voice coil will fit the gap. There are others, too, in different frame/voice sizes.

    Hope this helps.
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

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    Senior Member RMC's Avatar
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    Hi Edgewound,

    Glad you jumped-in this Thread since your practical knowledge of what fits where and how is probably ten times ours. The info you share with us is quite usefull. If the key word in your second para. is "properly", then the key word in your first para. is probably "identical".

    I know JBL has a "Goes into list" on its site but that info is limited to identifying which kit goes into what driver... no other possibilities given.
    It doesn't say as you did here today (examples) of which are identical frames, which may still work (with impact on response), and which ones can't be shared with another recone kit.

    Is there such a list of possibilities available for JBL drivers for example ? Please let me know. Thanks.

    Richard

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    Senior Member RMC's Avatar
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    Ken's advice on recones

    EDIT: TITLE SHOULD READ "SEEKING KEN'S INPUT ON SOME RECONES"
    Hi Ken,

    In this Thread (Post # 4) Ed Zeppeli indicated having reconed successfully 2205 (not A) frames with 2235H OEM recone kits, and in Post # 2 he mentioned a number of JBL frames as being interchangeable. In your expert opinion, NO I'm not trying to downgrade/question Ed's job (see next phrase), are these 2205/2235H really identical frames or second best ? As you can see from my Avatar I have a clear interest in knowing exactly what are my options as to best/second best/avoid for my own 2205H (JBL's list: 2225/2226 recones, which I may not necessarily like re different T/S. ). Mine are still all original from 1981, never "beaten"/on the road and used in vented-boxes. I suppose if there's a foam(? can't remember) inside the rear vent(like my 2214H) under the nameplate it may also have turned into crap after so many years (need to check), though the surrounds still look good but I don't know how long these usually last ?

    I'm re-foaming my 1991 2214Hs with specific, not generic, kit in my spare time (not much) and cleaning meticulously the gap with paper strips (under dust cap) and the sticky crap from the desintegrated vent foam, a real monk's job for which I've bought/made myself some "tools" (dentist's mirrors and pics, doctor's scalpel, modified small hand-held vacuum cleaner for hard to reach places-not the shop vac, etc). So far so good, one done still working, frame/gap/vent/cone cleaned as new. I'm planning to glue a small piece of speaker grille cloth over the back vent to replace the foam. Gluing replacement surround foam on the back of the cone will be a hassle, but I have to get there one day.

    Great idea Ken to have put on the market a line of JBL Reproduction recone kits, for the many of us with older drivers, but now left in the ditch by JBL's extended list of "obsolete/discontinued" stuff... What makes them different than other Aftermarket kits sold, as close as it can be to OEM ? Therefore delivering the same T/S one would expect from his driver ? I'm keeping an eye on these as I may need some in the future.

    I noticed on your site the list of clone recones: you have a 2205 A B/2225 H J kit, but none mentioned specifically for 2205H, any reason (like not enough of those left) ? Also your 2214H-1 kit has Aquaplas, mine don't, would still fit/perform the same ? My version of 2214H is with Faston Connectors, not push type.

    I also noticed for JBL reproduction cones price differences on your Web site VS your E-Bay pricing, examples: E-140 $235/$169 and 2245H $325/$279. Are these the same kits ? Is it re labour ? Bit confused.

    Thanks again.

    Richard

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    Senior Member edgewound's Avatar
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    EDIT: TITLE SHOULD READ "SEEKING KEN'S INPUT ON SOME RECONES"

    Hi Ken,

    In this Thread (Post # 4) Ed Zeppeli indicated having reconed successfully 2205 (not A) frames with 2235H OEM recone kits, and in Post # 2 he mentioned a number of JBL frames as being interchangeable. In your expert opinion, NO I'm not trying to downgrade/question Ed's job (see next phrase), are these 2205/2235H really identical frames or second best ? As you can see from my Avatar I have a clear interest in knowing exactly what are my options as to best/second best/avoid for my own 2205H (JBL's list: 2225/2226 recones, which I may not necessarily like re different T/S. ). Mine are still all original from 1981, never "beaten"/on the road and used in vented-boxes. I suppose if there's a foam(? can't remember) inside the rear vent(like my 2214H) under the nameplate it may also have turned into crap after so many years (need to check), though the surrounds still look good but I don't know how long these usually last ?
    Hi Richard,
    The AlNiCo frames and ferrite/ceramic frames are dimensionally identical in that lots of recone kits are interchangeable where the speaker becomes the model of the recone kit installed. They don't become actually identical in sound because the magnetic fields are improved inside the gap in the later SFG (Symetrical Field Geometry) ferrite motor models. they are better performers but substantially heavier. In a stationary playback system, heavier is better. Newton's Third Law.

    So...a 2205A reconed with a 2235H kit is spec'd by the factory as functionally identical to a a 2235H since the energy in the gap is supposed to be 1.2T for both models and the mechanical dimensions are the same. Actually though, flux densities among the AlNiCo motors can vary quite a bit while the ferrite SFG motors are far more consistent. That said...the AlNiCo units are just plain prettier and self shielding if that's an issue. 2225/2226 are really not suitable replacements for the 2235H but will work...make sound...if that's all that's available.

    The ferrite models had a foam vent filter which as everyone knows by now disintegrates and causes voice coil movement problems which can lead to failure. The AlNiCo models mostly have a cloth screen which doesn't cause this problem.

    I'm re-foaming my 1991 2214Hs with specific, not generic, kit in my spare time (not much) and cleaning meticulously the gap with paper strips (under dust cap) and the sticky crap from the desintegrated vent foam, a real monk's job for which I've bought/made myself some "tools" (dentist's mirrors and pics, doctor's scalpel, modified small hand-held vacuum cleaner for hard to reach places-not the shop vac, etc). So far so good, one done still working, frame/gap/vent/cone cleaned as new. I'm planning to glue a small piece of speaker grille cloth over the back vent to replace the foam. Gluing replacement surround foam on the back of the cone will be a hassle, but I have to get there one day.
    2214H/H-1 have a common failure mode due to it's substantial excursion capability, aside from the foam surround rot. The spider has a tendency to tear away from the voice coil/cone bonding junction. So long as the cone and voice coil are undamaged both surround and spider can be replaced for a good long term service fix. At the same time, the dome is removed and the foam vent screen can be replaced with a piece of grill cloth stretched tight when the adhesive grabs. Foam rot problem eliminated.

    Great idea Ken to have put on the market a line of JBL Reproduction recone kits, for the many of us with older drivers, but now left in the ditch by JBL's extended list of "obsolete/discontinued" stuff... What makes them different than other Aftermarket kits sold, as close as it can be to OEM ? Therefore delivering the same T/S one would expect from his driver ? I'm keeping an eye on these as I may need some in the future.
    Thanks very much!
    I refer to my kits as "reproductions" due to the attention to detail paid the assembly process, and also the application of the identical material as Aquaplas to the models that require it. I measure and apply the material to closely replicate or even match the moving mass to the JBL Engineering Standard. I try to get it dead on but I'm happy if it gets within a few grams difference. It's a time consuming process. I've seen lots of production cone assemblies that I've removed for recone that are as much as 20% away from engineering spec. Not enough material applied.

    I noticed on your site the list of clone recones: you have a 2205 A B/2225 H J kit, but none mentioned specifically for 2205H, any reason (like not enough of those left) ? Also your 2214H-1 kit has Aquaplas, mine don't, would still fit/perform the same ? My version of 2214H is with Faston Connectors, not push type.
    2214H/H-1 recone kit is C8R2214. The front of the cone is coated with black Aquaplas. If yours doesn't have Aquaplas, it's not a JBL kit. These woofer variants were used in the 4425 studio monitor and the L100t/t3. There was another manufacturer back in the 1980s or 90s that used a woofer that looked very much like a 2214H without Aquaplas. I think it was Mitsubishi.

    I also noticed for JBL reproduction cones price differences on your Web site VS your E-Bay pricing, examples: E-140 $235/$169 and 2245H $325/$279. Are these the same kits ? Is it re labour ? Bit confused.

    Thanks again.

    Richard
    The prices on eBay are for the recone kits only, with free shipping in the Continental US. The other prices you see on my website are total recones with parts and labor. I highly recommend the Full Service treatment to the AlNiCo motors. Disassemble the motor, clean any rust and debris from the pot structure with an anticorrosive gun oil, reassemble and recharge the magnet. Brand new equivalent restored motor. AlNiCo motors are typically down in charge by about 20% after some 40-50 years.

    You're most welcome. Hope this helps.
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

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