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Thread: The purpose of JBL E145

  1. #46
    Senior Member martin_wu99's Avatar
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    I like E145-8 in my 4628B
    46 lover

  2. #47
    Senior Member frank23's Avatar
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    I just bought a new old stock E145. I replaced one of my 2235's that I run in 4507 cabinets. As I run an active system with the m553 I summed the low channels and sent them both to the E145. it needs to loosen up of course, but I can hear it being faster than the 2235 already. Great driver it seems to be. Now I'll have to look for a second one! 1/3rd of the cone weight and 98dB sensitivity, nice! Lets see if I miss the really low end as it loosens up. I doubt it...

  3. #48
    Administrator Robh3606's Avatar
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    Hello Frank

    I have been using them for quite a while now. They are great drivers but they clearly don't do the last octave and a half. If you are used to the 2235's depending on the music I think you will miss the last octave. You have an advantage though you could always build a pair of B380's for fill in. You already have the 2235's.

    Rob
    "I could be arguing in my spare time"

  4. #49
    Senior Member gibber's Avatar
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    Alnico strength degradation

    Quote Originally Posted by gibber View Post
    Well, K145 values in that table are also a bit off...

    I got a pair of K145s recently and after measuring them for T/S, had them re-magged. After re-magging, i would have assumed them to meet table values. The pair changed as follows (note this is a early paper surround pair with a higher Fs than later 145-8 and 145-16 units had with their treated fabrix surrounds). A third unit is not re-magged yet and included just for a look at sample consistency (lots of Alnico loss evident in 2 out of 3 samples).

    Param JBL-value Bass1 re-mag Bass2 re-mag Bass3
    F0.......35 40.1 38.6 40,5 39,7 41.2 Hz
    Re.......8.8 8.8 8.8 8.4 8.4 8.0 Ohm
    fs........35 38.5 36.1 36.9 37.3 40.9 Hz (fs with me is sqrt of fl * Fh)
    Qms.....6.0 2.91 2.46 1.85 4.52 6.67
    Qes......0.3 0.31 0.26 0.45 0.26 0.38
    Qts......0.29 0.28 0.23 0.36 0.24 0.36
    fs/Qts..120 137 154 102 154 115 Hz

    All units are labelled "K145" with a second line on the label stating impedance as "8 ohms". In fact these might be considered 12 Ohm. Later units were called "K145-8" or "K145-16" and had DC resistances similar to E145-8 (ca 5.5 Ohm) and E145-16 (ca 12.5 Ohm).

    I just got another K145, this time the later version K145-16. There were auctions for two of these from the same seller, but the second unit looked too battered for my liking.

    The sample i got looks good cosmetically, but must have seen serious beating, too. The unit appears to have been reconed once with kit#64194 (Nomex former, fabric surround).

    Thiele Small parameters are hard to believe, but i measured twice to make sure it's correct:
    Param ... JBL-value ... meas. value
    F0..........35 ........... 35.9 Hz (impedance maximum)
    Re..........12.5 ........ 13.4 Ohm
    fs...........35 ........... 35.3 Hz (fs is sqrt of fl * Fh)
    Qms........6.0 .......... 3.03
    Qes.........0.3 .......... 0.44
    Qts.........0.29 ......... 0.4
    fs/Qts.....120 .......... 91.1 Hz

    Surely the Alnico loss is a good reason to look for E145 instead of K145 units
    Unless you have someone that can re-mag K145 for you

    I should get this K145-16 unit re-magged once i have a second one and report the changes. I guess that a Qts of 0.25 or so will result.
    Or maybe a "soft" re-magging with less current in the re-mag coil would be nice.
    Optimum bass extension acc. to Thiele-Small is to be had with a Q of 0.36 or so, if you dial in some amp output impedance and cable DCR
    Perhaps such Qts changes explain preference for the older Annico types over Ferrite ?

    Would be nice if anyone that has observed E145 ferrite strength degradation could share some details
    Last edited by gibber; 09-23-2012 at 09:13 AM. Reason: Spelling

  5. #50
    Senior Member frank23's Avatar
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    Quote Originally Posted by Robh3606 View Post
    Hello Frank

    I have been using them for quite a while now. They are great drivers but they clearly don't do the last octave and a half. If you are used to the 2235's depending on the music I think you will miss the last octave. You have an advantage though you could always build a pair of B380's for fill in. You already have the 2235's.

    Rob
    The E145 I bought was new old stock. It has only now begun to become a little looser. I had this when I had my 2235's reconed some years ago, the first weeks they sounded quite awful. I just bought a 2nd E145 chassis on Ebay that I'll have reconed in the next week so I'll have two "as new" E145 drivers.

    So I'll be only able to do a full comparison in a few weeks. But when I now switch from muting my left / right speaker thereby selecting the E145 / 2235, there is an obvious difference. The 2235 sounds "darker". I think the E145 integrates better with the 2123 it seems.

    Btw, building two B380's to support the E145 in the low end will severely challenge my wife's acceptance of my hobby :-))

  6. #51
    Senior Member gibber's Avatar
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    Horses for courses

    Quote Originally Posted by frank23 View Post
    The 2235 sounds "darker". I think the E145 integrates better with the 2123 it seems.

    Btw, building two B380's to support the E145 in the low end will severely challenge my wife's acceptance of my hobby :-))

    ==> But that's exactly what you would need to do, if your E145 T/S parameters have stayed firm at factory values over time.

    Using the Hoge formulae, i get an f3 of 71 Hz in an optimum tuning reflex cab (50 l, Q=7), assuming the E145 values from the 2008 JBL T/S data publication. Midrange SPL would be 97dB at 1W.
    That is really more of a cone midrange than a bass application, no wonder your 2235H sound "darker"

    A 2235H reaches down to 39Hz (-3dB) in 91 liters assuming a Q=7 enclosure with the same "official" 2008 source of JBL T/S data. SPL then is ca 94dB (a 4430 is specified at 93dB, so 1dB is eaten up by the integral passive crossover).

    If the E/K145 sound is what you like better, a battered '145 with fs=35Hz and Qts=0.38 results in the same 39Hz (-3 dB) in a Q=7 enclosure. You need 199 liters per side (and have the same wife acceptance problem as you'd have with the extra B380 subs). Only consolation (perhaps not for your wife) is that you look at a 96dB SPL for a watt, nice to have if running a vintage amp ...

    Ralph

  7. #52
    Senior Member frank23's Avatar
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    It has been posted here on this forum that the E145 T/S values as published by JBL cannot be correct as they do not match up like they should according to the T/S formulas. There probably was a typing error in the Vas.

    As cabinets I use the 4507, which is a 150liter cabinet that can be tuned by covering 0,1,2 or 3 of the ports (or 4, then its closed). The E145 do not go as low as the 2235 will in the 4507, but they go low enough, . But the sound difference to me lies in the speed of the E145 drivers. It has more "snap". Although I am only using them until about 175Hz.

    My "wife" worry is having to use two 4507's per side. One with the 2235 tuned as a B380, the other with the E145 from 40Hz up...

    I think I'll stick with the single 4507 per side. Either with one 2235 or one E145.

    Btw, I just won an Ebay auction for a E145 basket that I am going to have freshly reconed, so I'll have two factory fresh E145 drivers!

  8. #53
    Administrator Robh3606's Avatar
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    assuming the E145 values from the 2008 JBL T/S data publication.
    VAS is 427 not 274. Look at the second page of the thread.

    Rob
    "I could be arguing in my spare time"

  9. #54
    Senior Member gibber's Avatar
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    Quote Originally Posted by frank23 View Post
    It has been posted here on this forum that the E145 T/S values as published by JBL cannot be correct

    ...

    Btw, I just won an Ebay auction for a E145 basket that I am going to have freshly reconed, so I'll have two factory fresh E145 drivers!


    I wish you best of success with the new driver. Do you have a NOS recone kit to restore it or is such still available for E145 ?

    I took your and Rob's hint at Giskard's remarks on page 2 and for the first time noticed E145 cone to be of 20g lower mass than K145's (??).
    Recalculation using Vas=427 l, Qts=0.25 and Fs=35 Hz get me a new enclosure of 85 liters, a whopping 101 dB ref SPL. 70 Hz (-3 dB) in a low loss (Q=7) enclosure still qualifies E145 more for lower mid than for bass, though. I read that 4 cu ft (108 liters) is JBL's recommendation, not so far away from the Hoge alignment i calculated. The 4 cu ft box will give something like a Bessel type response, with very gradual roll-off and -10dB at ca 45Hz.

    Or am i doing something wrong ?

    In any case, both alignments would be compensating nicely for placement close to floor and side walls, so given your experience it appears in-room practice needs to be dialled in when looking at theory ...

  10. #55
    Senior Member frank23's Avatar
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    I have bought the last new C8RE145 recone set at the JBL Pro representative in Belgium. I don't know if new ones can be ordered. They did not have any new chassis left. If needed, I can enquire for you if new ones canbe ordered?

    I just compared the 2235 and E145 in 4507 cabinets and the E145 misses the lowest organ notes, but does not sound like a driver that cuts of at 70Hz. I have the E145 4507 cabinet now tuned with 3 ports open, whereas I use the 2235 in the 4507 with two ports open.

    But how do your calculations for the E145 compare to the published Everest graphs? I think the Everest is said to have an 8 cu-ft enclosure tuned to about 30-35Hz so to see and uses the E145 (although it is called 150C-4 or so). See 2pi vs 4pi curves.

    Btw, I have an old review of the Everest by Ken Kessler in HiFi News & Record Review and he calls the suggested addition of a DD50000 (what is that?, a B460?) subwoofer "frightening". He says it is "flat to 40Hz".


  11. #56
    Senior Member gibber's Avatar
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    Quote Originally Posted by frank23 View Post
    I have bought the last new C8RE145 recone set at the JBL Pro representative in Belgium. I don't know if new ones can be ordered. They did not have any new chassis left. If needed, I can enquire for you if new ones canbe ordered?
    Would be fantastic if your contact could get hold of a C16RE145 or still have one in stock. If it doesn't cause undue effort, let me know if i'm as lucky as you are.


    Quote Originally Posted by frank23 View Post
    But how do your calculations for the E145 compare to the published Everest graphs? I think the Everest is said to have an 8 cu-ft enclosure tuned to about 30-35Hz so to see and uses the E145 (although it is called 150C-4 or so). See 2pi vs 4pi curves.
    The calculator i have used unfortunately has box volume as an output parameter only, but an 8 cu.ft Everest cab will just underdamp the response a little more than the 4 cu ft std.JBL cab already does when compared to the Hoge-formula box of 85 liters. Makes Everest kind of an "Onken" for E145/150-4series. Onken alignments add a little "hump" near the tuning frequency, something that doesn't happen if tuning freq is in proximity to the -3dB point. Actually, you can see the hump in the published Everest halfspace data.


    Quote Originally Posted by frank23 View Post
    Btw, I have an old review of the Everest by Ken Kessler in HiFi News & Record Review and he calls the suggested addition of a DD50000 (what is that?, a B460?) subwoofer "frightening". He says it is "flat to 40Hz".
    I bought HFN/RR a lot in the 80s/90s exactly because of KK's writing, often hilarious in style, never trying to obscure the subjectivity of his view. He liked small UK-made garage amps and Britiish 2-way subminiature speakers at the time. I'm not surprised a man rightly focussed on midrange reproduction then was wary of a response "flat to 40Hz"

    Ralph
    Last edited by gibber; 09-26-2012 at 10:08 AM. Reason: Spelling

  12. #57
    Senior Member frank23's Avatar
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    I just got the message my 2nd E145 has arrived at the reconer, so I should have it back in a week or so I guess. I have now been playing with the first E145 for over a week. I have put it in a 4507 box with 3 ports opened and I have put the M553 on LFsum, so it outputs both channels to the single E145. I must say that I feel it integrates with the 2123 mids very well. In my mind better than the 2235's did.

    The bass sounds much "faster". There is a nice article here about "fast bass" that I think has a lot of thruth in it, and I think to whatever reason (lower cone mass, underhung coil, different cone shape) the E145 in my setup integrates very nicely with my 2123's:
    http://www.soundstage.com/maxdb/maxdb061999.htm

    My experience however is that a new or freshly reconed driver needs to be played in and bolts need to be retightened over a number of weeks. The sound can turn quite bad, before all is settled.

    @gibber I have inquired about the C16RE145, but haven't received an answer yet.

  13. #58
    Senior Member gibber's Avatar
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    Quote Originally Posted by frank23 View Post
    The bass sounds much "faster". There is a nice article here about "fast bass" that I think has a lot of truth in it, and I think to whatever reason (lower cone mass, underhung coil, different cone shape) the E145 in my setup integrates very nicely with my 2123's:

    ...

    @gibber I have inquired about the C16RE145, but haven't received an answer yet.

    Hello again,

    i got myself two 115 l cabs made from stone (seller said it's polished slate). Unloaded they are 150 kg each. Took me a while to find people willing to help me lift them upstairs. The picture shows them with K145 (re-magged bass1&bass2 as per table elsewhere in this thread). So these K145s now come with Q values as low as E145. Result is, well, not enough bass, but fast. I EQ'ed with +2dB at 86Hz, +3dB at 63Hz and +7dB at 41Hz to make it flat to around 37Hz (didn't use a shelf to avoid the room modes). The volume is slightly larger than the recommended 4 cu ft. It is tuned to 30Hz (i got the cabs this way). I tried re-magged 2220Bs as well, Qts very similar, sound was fast, but somehow not as punchy. Will try EVI-15, 416A, and bass guitar units by Gauss and Fender (D140F, see pic) next.
    Attached Images Attached Images   

  14. #59
    Senior Member frank23's Avatar
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    Those look nice, but almost too narrow! How deep are the cabinets? I run the E145 in de 4507 cabinet with 3 ports open, I like it less with only 2 ports open.

  15. #60
    Senior Member gibber's Avatar
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    Quote Originally Posted by frank23 View Post
    Those look nice, but almost too narrow! How deep are the cabinets? I run the E145 in de 4507 cabinet with 3 ports open, I like it less with only 2 ports open.
    Hi Frank,

    the cabinets are 65cm deep, hence the (pictured, relatively long) Musique Concrète Le Cléac’h 322 horn + 2440 driver combo has ample space on top. I believe even a Jabo 72alu + DH1A might just fill in. My fav HR6040A + 288G is too deep at 70cm, but would be OK at 44cm width if placed upright. The cabs are 43cm wide but the chamfered edges and the extra space for the 145's "depth charge" on top of the std JBL15" frame make for the visual "just fit" you noticed. Actually, on the 145's outside there is only 2 or 3 mm each way before the chamfer of the cab starts. You must have guessed by now that inside space is far less crammed. The K145 all-paper ass'y is smaller than most JBL 15" cones, hence in-the-box there is actually enough breathing possible to the sides.

    The setup is x/o'd at just above 500 Hz using either BSS334T in NTM36 mode or Dolby Contour crossover in IIR24 mode and time delay correction. Amps are #26/LD-LL1660S/801A-PP/Tango-OPT for bass and a #46-SE w/ BlackArt iron for mid/treble. Nice setup, but installed in quite a lively space -- given this system is "guest" in my son's room, i'm rather careful w/ suggestions on sonic treatment, er, room decoration ;-)

    What's the tuning freq w/ three or two ports in your 4507 cabs?

    Ralph

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