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Niklas Nord
06-21-2003, 11:26 AM
What is/whas the purpose of the JBL E145 15" driver ?
Is there any replacement?


The frame seems to be really huge if you compare to
an 2225 15" driver. . .

4313B
06-21-2003, 12:53 PM
http://www.lansingheritage.org/html/jbl/specs/pro-comp/k145.htm

http://www.lansingheritage.org/html/jbl/specs/pro-comp/k-series.htm

http://www.jblpro.com/pages/pub/components/eseries.pdf

Robh3606
06-21-2003, 02:00 PM
I would love to get my hands on a pair of them to drop in my mains. My 801C is based on it and it is one really nice sounding driver. Vocals are great, fast, effortless and clear as a bell. And bass is well just great. I have on the DTS Hell Freezes Over right now. With Timithy B Schmidts bass and the vocals Don Henley and the rest through the center. Definately worth a listen.

Rob:)

boputnam
06-21-2003, 02:46 PM
JBL made a point of differentiating between the two applications - sound production and sound reproduction - the former being transducers for electronic instrument cabinets, and the latter being the focus of most on this forum (HiFi speaker components and cabinets).

http://www.lansingheritage.org/html/jbl/reference/tech1-3a.htm

I too, love the sound of the E-series, and have made sure the guitar player in my band swapped into the E110's (with stunning results... ;) ) for his Fender tube amps, but I have not dropped E-seires (or comparables) into HiFi applications, finding them a bit "brash" for that application.

Others out there have experiences, pro, con? :confused:

Niklas Nord
06-21-2003, 03:03 PM
I was talking with a man here in sweden who liked
the e-145 more than the 2235 up to ca 600hz, more
attack he said..

He used it with 2202, 2245 in a custom built high end
model loudspeaker.

Robh3606
06-21-2003, 03:10 PM
Hey Bo

You are right they do diferentiate between the two groups. The E-145 is very special as far as the E group is concerned. It has a underhung coil and is very linear driver. Just like the 150C K-145 where you can trace its lineage or the LE-15A or Altec 604. This makes it well suited for sound reproduction/home hi-fi. It also has a very powerful motor on a very light cone so it is really fast and clear. Take a look here

http://www.lansingheritage.org/images/jbl/reference/tech1-3a/page06.jpg

You should really take a look at the whole documnet. Lots of good stuff there.

Rob:)

Niklas Nord
06-21-2003, 03:13 PM
That was a great page indeed !!

boputnam
06-21-2003, 03:25 PM
Yea, Rob, I know. The discussion of the different surround compliances and designs I found very interesting, too. I recalled having read this page (p6) when Giskard was recently harping on the importance of surround integrity (and uniformity) while collecting meaningful measuring of cabinet tuning.

A very critical element in transducers performance.

4313B
06-21-2003, 04:11 PM
"when Giskard was recently harping on"

harp harp harp harp harp

boputnam
06-21-2003, 04:22 PM
"dwell on" is more along the lines of what I was thinking.


But maybe "emphasized" is more appropriate... ;)

Either way, PLEASE KEEP IT UP!

Earl K
06-21-2003, 04:26 PM
Hi Rob

I would love to get my hands on a pair of them to drop in my mains. Robh:)
It's so true, so many good speakers, so little real space & time to enjoy them all. I too would like a pair , just to check out the speed/quickness thing . Would also like a pair of K145(s) because it has a heavier cone / quite similar in the cone weight to the 2220/130A but still with that huge motor. Really do need a "Noahs' Ark" of this stuff to arrive at the perfect "personalized" system.

regards <> Earl K

4313B
06-21-2003, 04:27 PM
"I was talking with a man here in sweden who liked
the e-145 more than the 2235 up to ca 600hz, more
attack he said.."

Well shoot, I was going to go over the TS parameters in a post but, true to form, the JBL published numbers for the E145 are all jacked up. :D

Robh3606
06-21-2003, 04:42 PM
Well????

Rob you can't stop now. Do you know what the correct values are?? :D

Hello Earl

Yeah you sure are right about that! I don't have space for one more driver unless of couse I see another sweet E-Bay deal!! Never enough time.

Rob:)

Earl K
06-21-2003, 05:14 PM
Hi RobG
You and I went through this a couple of forums ago. What TS numbers were/are wrong. I remember you reporting that JBL said to measure it yourself,,, etc. The numbers I use seem to give the appropriate curves for this class of speaker. Here's a pdf of a 2 cu' , 50 Hz tuning I did quite a while ago ( ignore the date stamp ) . How does this curve compare to what you see with your tuning-prediction software?

regards <. Earl K

MikeM
06-21-2003, 05:17 PM
Ive had these magnet assblys reconed with 2235H kits. The cone traveled more on the 145 magnet then the 2235h mag assbly. I bet the 145 wiil sound great for upper bass and have higher power cabable but will loose below say 40 hz. In my application the 2235H was smoother. woulnt ming hearing a stock pair of E145 good luck

4313B
06-21-2003, 06:24 PM
Originally posted by Earl K
Hi RobG
You and I went through this a couple of forums ago. What TS numbers were/are wrong. I remember you reporting that JBL said to measure it yourself,,, etc. The numbers I use seem to give the appropriate curves for this class of speaker. Here's a pdf of a 2 cu' , 50 Hz tuning I did quite a while ago ( ignore the date stamp ) . How does this curve compare to what you see with your tuning-prediction software?

regards <. Earl K

Well for one thing...

Given a value for Fs of 35 Hz, Mms of 0.055 kilograms, and Sd of 0.090 square meters, Vas SHOULD be ~427.7 liters instead of 274.7.

This is given by:
Vas = (2 * pi * Fs)^2*Mms)^-1 * p0 * c^2 * Sd^2 * 10^3
Where Vas is in liters
Mms is in kilograms
p0 is 1.18 kilogram/cubic meter (mean density of air)
c is 345 meters/second (speed of sound)
Sd is in square meters

Dyslexia perhaps?
I think using 427.7 instead of 274.7 jacks up the reference efficiency though... I'd have to work through it...

4313B
06-21-2003, 06:59 PM
Anyway, back to:

"I was talking with a man here in sweden who liked
the e-145 more than the 2235 up to ca 600hz, more
attack he said.."

Looking at the TS parameters both drivers have the same Qts, the 2235H has a bit better mechanical control with it's lower Qms and the E145 has a bit better electrical control with it's lower Qes.

The 2235H clearly has a "better" Bl factor but...

155 grams / (20.5 Newton/Amperes * (1/6.0) Amperes) = 45.4 grams/Newton

55 grams / (16.1 Newton/Amperes * (1/5.7) Amperes) = 19.5 grams/Newton

Wow! If my math is correct, I guess we can see why the E145 has such a nice attack :)

boputnam
06-21-2003, 07:18 PM
I've noticed some myself - in the 1982 Pro brochure, p5 JBL appears to have swapped the Enclosure Volume figures for the 4345 and 4355...

Niklas Nord
06-22-2003, 03:59 AM
Great, this thread has become wery interesting.
Is the e-145 a rare object in the USA?

Are there one alnico version and one ferrite version ?

4313B
06-22-2003, 06:12 AM
No the E145 isn't rare.

Note that it's the same transducer as the 150-4H (Everest).

http://www.audioheritage.org/html/profiles/jbl/everest.htm

The K-series are alnico, the E-series are ferrite. JBL increased the flux densities in the E-series though...

Note that these TS parameters haven't been checked yet so some might be "wrong"

***********
K120, K151, E120, E145 look suspect

4313B
06-22-2003, 10:42 AM
Hello,

If someone has an E145, I need to know the effective piston diameter, preferably in millimeters. I already have "published" notes, I need the "real deal".

Thanks

Robh3606
06-22-2003, 02:17 PM
Well I can measure my 801C cone. It's different cone kit than the 145. Don't know if it because of the central spider or if the cones/surround are different.

Rob:)

JBL Dog
06-22-2003, 04:11 PM
Originally posted by Giskard
Hello,

If someone has an E145, I need to know the effective piston diameter, preferably in millimeters. I already have "published" notes, I need the "real deal".

Thanks

Giskard

I have three E145's. One NOS, two that are reconed with what appears to be a generic kit ("10455" stamped on cone.... looks exactly like the JBL kit, but slightly heavier).

Let me know how to measure the "piston diameter" and I will get you a number. :D Sorry, I'm pretty much a novice when it comes to the technical stuff :confused:


This message comes from JBL Dog :cool:

4313B
06-22-2003, 04:24 PM
Hi JBL Dog,

Measure from the middle of the surround :) Thanks!

JBL Dog
06-22-2003, 07:46 PM
Giskard:

I measured it to be exactly 13.25 inches. A conversion to millimeters is 336.55. Hope this helps. :)

This message comes from JBL Dog :cool:

4313B
06-22-2003, 07:55 PM
Great! Thanks a bunch :)

So that means the Vas of the E145 is 427.7 liters instead of the published 274.7 liters. It makes sense since JBL likes to put this driver in a 4.0 cubic foot volume tuned to 40 Hz.

sa660
06-23-2003, 06:36 AM
Originally posted by Robh3606
I would love to get my hands on a pair of them to drop in my mains. My 801C is based on it and it is one really nice sounding driver.
Rob:)

ROB,
I have 2 E145 that need recone and I am wondering about getting them done.
Can you describe the frame of the 801C?
The E145 has a thicker frame about 3/4 " thick to allow for a deeper cone that usual JBL chassis. Is the 801C the same?

Do you have characteristic of the vents and volume of the box for the 801C.

Regards,

4313B
06-23-2003, 08:23 AM
I don't know if this helps but one can see the differences in these baskets:

http://www.jblproservice.com/pdf/Discrete%20Sales%20Models/2235H.pdf

http://www.jblproservice.com/pdf/Discrete%20Sales%20Models/E140-8-16.pdf

http://www.jblproservice.com/pdf/Discrete%20Sales%20Models/E145-8-16.pdf

http://www.jblproservice.com/navigation/Discrete%20Sales%20Models.html

I can't find an 801C though.

Robh3606
06-23-2003, 08:40 AM
The 801C uses the same frame as the E-145. The diference between the volumes would be the volume taken by the 2425S hanging off the back. Take a look at the attached photo. There is a recess in the UREI cabinet the frame is thicker than it looks in the photo. If you talk to JBL they told me to use the T/S for the E-145. I have always wondered about that though looking at the -3db for the 811C monitor. I think they have the box tunned tight for maximum transient response.

Rob:)

Robh3606
06-23-2003, 05:49 PM
Some decent pictures

Robh3606
07-13-2003, 01:15 PM
Well I got one!! Have another coming in about 2 weeks after its reconed. There is no doubt about the 801C similarity with the E-145. The cone texture, rolled surround, and frame are identicle. Least I can't tell them apart. Now I have to drop it in and start listening.

As a side note I asked Giskard to run a couple of plots on his software Bass Box Pro 6 and there seems to be a difference on how the programs tune the boxes. I will restart the WinIsd thread for those interested.

Rob :smthsail:

Alex Lancaster
07-13-2003, 08:56 PM
As far as I know, the basket of all 4" coil speakers are the same; The 145's used a circular spacer about 1" thick, which made the cone have a smaller included angle, thus stiffer, the surround was wider, for more excursion.

They were made mainly for organ.

I used some (about 6 feet long horn loaded) in disco installations, but liked the E140's or 2205H's better.

I have 2 original brand new in the box E140-8 recone kits (about 20 years old) that I would trade for 2245H recone kits.

Thanks: Alex

4313B
07-14-2003, 05:52 AM
"the basket of all 4" coil speakers are the same"

Nope. It is true though that with the move from alnico to SFG ferrite assemblies the number of variations was reduced.

Don McRitchie
07-14-2003, 07:18 AM
The K/E145 and 150-4 baskets are different, but are not all the other 15" baskets the same? I know this wouldn't apply to recent speakers, since JBL has developed numerous uniqe designs in the past few years.

4313B
07-14-2003, 10:01 AM
"are not all the other 15" baskets the same?"

Ok, let me back up a second. If we are talking ONLY about the frame and not the magnetic assembly bolted to it then yes, one is probably correct in stating that "the basket of all 4" coil speakers are the same". Once you bolt the magnetic assembly onto the frame it's a whole new ballgame. For instance, the E130/E140... SO many people think (I erroneously did too) they can pop a 2225H cone kit into one of these bad boys and end up with a 2225H. There's an ad on eBay right now claiming that very thing. Heck, even Greg forgot that the E130/E140 baskets were different and he was in on the design of the things! When I reminded him that they had a different flux density he exclaimed "Oh that's right! Those things have a 1/8" thicker magnetic assembly which will shift everything up!" Sure enough, we went and measured a 2225H magnetic assembly and then an E130 magnetic assembly and the E130 was indeed 1/8" thicker. Brutally powerful motors BTW...

Mr. Widget
07-14-2003, 10:45 AM
Actually not even the baskets are the same between various 15s. A number of years ago I used a blown D130 as a fit template for some cabinets I was building. I was using the cabinets to do some comparisons between a pair of 60's LE15As and 70's LE15Bs. I don't remember which one was larger, but one pair dropped in and the other pair required cutting the hole another 1/16" larger.

Then there are the much older models with the gussets, these can only be rear mounted.

Alex Lancaster
07-14-2003, 10:45 AM
By baskets, I meant of course just the aluminum die cast part, not the magnet, pole piece, top plate, etc.

In my earlier post I should have said E145-8 recone kits.

Thanks: Alex

mtchyz250f
03-11-2011, 11:51 AM
The link from post 4 no longer works:
http://www.lansingheritage.org/image...-3a/page06.jpg

TriVista
01-26-2012, 05:05 PM
The link from post 4 no longer works:
http://www.lansingheritage.org/image...-3a/page06.jpg

Google or Bing "site:www.lansingheritage.org (http://www.lansingheritage.org) tech1-3a" as quoted and you'll find both the JBL Tech Note 1.3a (http://www.lansingheritage.org/html/jbl/reference/notes/tech1-3a.htm) and the commendable Lansing Heritage sitemap (http://www.lansingheritage.org/sitemap.htm)

57BELAIRE
02-01-2012, 10:27 AM
The K/E145 and 150-4 baskets are different, but are not all the other 15" baskets the same? I know this wouldn't apply to recent speakers, since JBL has developed numerous uniqe designs in the past few years.

I swapped out my L300 woofers (136H) for a pair of E145's awhile back just for grins and decided to leave them in cause they sounded so good (not better, just different). I was also thinking about the same
swap for the 150-4C's in the Paragon (to give them a rest) but saw Don's post and have reservations.
Any thoughts?

edgewound
02-02-2012, 08:20 AM
I swapped out my L300 woofers (136H) for a pair of E145's awhile back just for grins and decided to leave them in cause they sounded so good (not better, just different). I was also thinking about the same
swap for the 150-4C's in the Paragon (to give them a rest) but saw Don's post and have reservations.
Any thoughts?

The E145 is the modern equivalent of the 150-4C. Might be a tad more efficient. It's a beast of a 15". Clean, loud, linear, low, punchy. Doesn't have the low reach of the 2235H/136H due to the higher Fs, but what it lacks there, it makes up for in all the other areas.

Should really shine in a Paragon.

ratitifb
02-02-2012, 02:17 PM
E145-8 in the L300 :dont-know: what about the port tunning ?

Robh3606
02-02-2012, 08:14 PM
what about the port tunning ?

It's about 10Hz to low so it really won't make all that much of a difference with the E-145

Rob:)

57BELAIRE
02-03-2012, 05:27 AM
E145-8 in the L300 :dont-know: what about the port tunning ?

If you're familiar with my posts in general you'll know I let my ears be the judge....and the 145's sound pretty darn good in those cabs. As for "port tuning"....I'll leave that to the experts ;)

gibber
07-15-2012, 05:22 PM
No the E145 isn't rare.

Note that it's the same transducer as the 150-4H (Everest).

http://www.audioheritage.org/html/profiles/jbl/everest.htm

The K-series are alnico, the E-series are ferrite. JBL increased the flux densities in the E-series though...

Note that these TS parameters haven't been checked yet so some might be "wrong"

***********
K120, K151, E120, E145 look suspect


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).

Note that Qts values for this Alnico bass after re-mag are very close to what is stated by JBL for the Ferrite version E145.

Sorry for the formatting, i did not take away the spaces. Hope its useful to someone

martin_wu99
07-16-2012, 01:17 AM
I like E145-8 in my 4628B:D

frank23
09-15-2012, 03:39 PM
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...

Robh3606
09-16-2012, 08:17 AM
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:)

gibber
09-23-2012, 10:07 AM
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

frank23
09-23-2012, 02:41 PM
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 :-))

gibber
09-24-2012, 11:15 AM
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

frank23
09-24-2012, 12:58 PM
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!

Robh3606
09-24-2012, 06:29 PM
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:)

gibber
09-25-2012, 02:01 AM
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 ...

frank23
09-25-2012, 03:30 AM
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".

http://www.lansingheritage.org/images/jbl/specs/home-speakers/1985-everest/page10.jpg

gibber
09-25-2012, 04:12 PM
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.



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.



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

frank23
09-28-2012, 03:01 PM
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.

gibber
11-04-2012, 03:37 PM
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.

frank23
11-12-2012, 12:27 PM
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.

gibber
11-13-2012, 12:35 PM
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

frank23
11-14-2012, 02:15 PM
This is what Zilch on the forum measured for the tuning frequencies:
http://www.audioheritage.org/vbulletin/showthread.php?21726-JBL-2235H-in-the-house&p=216106&viewfull=1#post216106


I've measured and documented 4507 tuning several times in these forums.

Here's my recollection, but y'all can look it up to be sure:

4 ports open = 40 Hz, the stock tuning for 2225H, E140, and similar.

One port closed = 34 Hz, stock 4430 tuning.

Two ports closed = 28 Hz, extended bass or sub duty, which is how I run them mostly....

So I'm running the E145 with one port closed in the 4507, so tuned to about 34Hz.

gibber
11-14-2012, 03:02 PM
This is what Zilch on the forum measured for the tuning frequencies:
http://www.audioheritage.org/vbulletin/showthread.php?21726-JBL-2235H-in-the-house&p=216106&viewfull=1#post216106


So I'm running the E145 with one port closed in the 4507, so tuned to about 34Hz.


That two-port 28Hz tuning you like less is very similar to the 30Hz i have here. Instead of changes on the ports my cabs have, i just tried using a beefy transistor amp and gave it a 10ohm resistor in series to my (early version) K145's ca 9ohm coil dc resistance. New Qes' equals (Rg + Re) / Re * Qes, so Qes goes up to 0.52 or so and hence new Qts is around .49 (see Qms in tables earlier in this thread).
Result is a more "normal" bass sound, the mid is similar as before, and subjective speed is slightly less, imho not too much so to offset advantages in the deeper register. Mid output subjectively is down by 2dB (should be 3 dB but the higher Qts with series-R maybe reinstates some of the premature-but-gradual rolloff that a driver of Qts=0.23 w/o series-R has).

frank23
11-16-2012, 02:44 PM
But then what happens to the amp damping the cone when you put a 10 ohm resistor in between?

ivica
11-17-2012, 10:33 AM
But then what happens to the amp damping the cone when you put a 10 ohm resistor in between?

As resistor being 'in series with the driver" the amplifier would "see" less load, , so less current, so "more comfortable"

regards
ivica

gibber
11-17-2012, 02:22 PM
But then what happens to the amp damping the cone when you put a 10 ohm resistor in between?

Qts influences what we hear frequency/impule response-wise. Qts expresses the composite of electrical and mechanical damping near resonance. So even if the amp dampens less, there is still the same mechanical damping of the cone. I consider Qts=.23 for K145 after re-gaussing (E145 is similar) as too low from what i heard: "fast" as you rightly said, but overdamped, lean bass. Some drivers work well having such low Qts, but their fs/Qts (or fs/Qes) ratio is lower.

One way around it would be to mod the speaker or box mechanically in order to alter damping; or do it through electrical changes. The 10 ohm resistor will give the amp less control over the coil (coil impedance divided by feeding impedance equals "damping factor"). I reduced damping factor to about unity. So the amp is less able of damping the cone, intentionally so in my case, as i deemed the sound overdamped.

If you deem a driver Qts' of 0.49 a bit high for reflex applications, you may want to optimize the resistor for what are called "B4 maximally flat" alignments. According to literature, in a lossless enclosure this is achieved at a driver Qts of around 0.38. Any higher Qts (or Qts' in my case) and you get some amount of undesired ripple in your response. From the tables earlier in this thread you can see Qms of my old version paper-surround driver is around 2.5. Your E145 will be similar, maybe 3.1. Using Qts' = Qms*Qes' / (Qms+Qes') gives me a "target" Qes' of ca .44 to achieve Qts' just shy of .38. Choose Rg' as Qes' / Qes * Re - Re. Note that Rg' is the addition of amp, resistor and cable resistance. For many transistor amps and for short runs of cable, it's often safe to assume zero ohms for both. Then, 4.7 ohm or 5.1 ohm are then the E6 resp E24 std resistor values for targeting your E145 at Qts' 0.38. Try it out, it's easily done. Or try a 10 ohm resistor first and then parallel a second 10 ohm after listening in for a while

Ralph

frank23
12-23-2012, 10:12 AM
Thanks for the thorough explanation above btw. I have yet to try and add the 10 Ohm. Recently I had a pair of Event Opal studio monitors on loan. They are fabled for their low end, which is enormous for a speaker their size I must say. But when I hooked up the E-145's again. Man, that is so much better. The 145' reach much lower, and give much more weight to the low end. I can't imagine them cutting of fairly high as you say. The Opals are supposed to go to 35Hz in room, but the E-145 in the 4507 have much more weight to them.

gibber
12-30-2012, 12:15 PM
It's sacrilege, i know. Would still be interested to hear what those that jumped their own shadow have found out, though ;)
New year day is often pretty boring - why not get hold of a pair of resistors. Can be pretty low wattage with high SPL cones like E145, unless you go for PA sound levels

Enjoy the fireworks tomorrow
Ralph

ivica
06-20-2013, 06:12 AM
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.

......!

I think for E145 it has to be Vas=427.7 lit

regards
ivica

4313B
06-20-2013, 06:47 AM
I think for E145 it has to be Vas=427.7 litersThat is what we arrived at.
It's sacrilege, i know.Mark Gander and I went over this back in the late seventies with respect to his overdamped 124A aka 2203 and 136A aka 2231 designs, Qts = 0.14 and 0.19 respectively, along with various series resitor values. In the end it was determined that the DCR of the low pass inductor coupled with careful volume/tuning ended up being the best solution. 4315 volume/tuning and 4331/4333/4343/L300 volume/tuning along with their respective passive networks and whatever EQ was going to be applied in the Studio.

One of the hallmarks of the traditional JBL transducers was their low Qts. Arguably the 124 and 136 went a tad overboard. ;)

In any case, examine the low pass filter in the DD55000, which used a variant of the E145. Unknown would be the DCR values of the coils.

frank23
11-14-2014, 01:19 PM
I finally tried this today, after having tinkered with it on and off over the past few weeks.

With a measurement microphone and pink noise I measured 40Hz in comparison to 100Hz. With a 4.4Ohm resistor in series with the E145 40Hz was at -14dB compared to 100Hz. Without resistor 40Hz was at -13dB compared to 100Hz. Of course due to the resistor the total level was different, but its the difference between 40Hz and 100Hz that we are looking for here. I could see no improvement in lf extension when inserting a resistor. in fact extension suffered a little. The E145 was in a 4507 5cu 150l cabinet. I think I had it with all 4 ports open, but I was tinkering with that also, so I can't recall that exactly, might even have been closed :-)

I know, 1dB is not much, but the measurement was repeatable, it definately showed that there was no gain in LF extension with the resistor in place with the E145 in the 4507 cabinet.

frank23
11-23-2014, 03:01 AM
It may sound strange regarding the T/S data, but I am now using the E145 in a closed 4507 cabinet. I moved it forward 30cm, and the bass sounds very fast. I probably miss the lowest octave, but the in-room bass extension is much better than I expected and is very controlled with great energy. Organ is just fine. Maybe home theatre fans would miss a bit of the thunder of a helicopter flying over or so, but I listen to music.

I crossover to the 2123 quite low at 100Hz, maybe the rising output from the E145 fills in the missing 2123 output between 100-200Hz and makes it a nice match that way, I'm not sure. Experiments with lowering the Qts through resistors were not satisfactory for me, so they are hooked up straight to the amp again.

frank23
01-03-2015, 01:00 PM
I have seen the E145 frequency response curve as measured by Greg Timbers many times, but have never seen the version I found here, with the 2nd and 3rd harmonics added in the graph (note: raised by 20dB).

http://www.audioatrium.com/forum/files/e145_914.jpg

Would anyone know what the vertical scale here is? If it is 2dB for every horizontal line, then this E145 is about the best low-mid driver ever with a 2nd harmonic at about -70dB at 150Hz. It then betters the current 15" from the DD66000. If it is 1dB for every horizontal line, distortion at 150Hz is still low at -45dB, but not really special.

Earl K
01-03-2015, 02:47 PM
I have seen the E145 frequency response curve as measured by Greg Timbers many times, but have never seen the version I found here, with the 2nd and 3rd harmonics added in the graph (note: raised by 20dB).

http://www.audioatrium.com/forum/files/e145_914.jpg

Would anyone know what the vertical scale here is? If it is 2dB for every horizontal line, then this E145 is about the best low-mid driver ever with a 2nd harmonic at about -70dB at 150Hz. It then betters the current 15" from the DD66000. If it is 1dB for every horizontal line, distortion at 150Hz is still low at -45dB, but not really special.

I'm quite confident that the displayed 1700hz breakup peak is not 16db high / I'll believe 8db .

I'll support ( the opinion ) that the total vertical scale being displayed, is 40db .

Keep in mind that the chart shows 9.2 volts ( as the applied power ), so it's still very clean ( IMO ) .

:)

frank23
01-03-2015, 02:57 PM
And if the noted voltage is correct, it should probably say "10W@1m", not "1 W@1m" as it says now. It looks like the "0" was removed. I have no idea how distortion scales with level though.

Earl K
01-03-2015, 04:14 PM
And if the noted voltage is correct, it should probably say "10W@1m", not "1 W@1m" as it says now. It looks like the "0" was removed. I have no idea how distortion scales with level though.

Here's a ( very ) handy online calculator for ( decibel > THD distortion conversions ) (http://www.sengpielaudio.com/calculator-thd.htm).

:)

Ian Mackenzie
01-03-2015, 07:16 PM
That two-port 28Hz tuning you like less is very similar to the 30Hz i have here. Instead of changes on the ports my cabs have, i just tried using a beefy transistor amp and gave it a 10ohm resistor in series to my (early version) K145's ca 9ohm coil dc resistance. New Qes' equals (Rg + Re) / Re * Qes, so Qes goes up to 0.52 or so and hence new Qts is around .49 (see Qms in tables earlier in this thread).
Result is a more "normal" bass sound, the mid is similar as before, and subjective speed is slightly less, imho not too much so to offset advantages in the deeper register. Mid output subjectively is down by 2dB (should be 3 dB but the higher Qts with series-R maybe reinstates some of the premature-but-gradual rolloff that a driver of Qts=0.23 w/o series-R has).

Possibly another work around is to explore DB Keele 6th order paper on his web page and run the numbers.

My estimate is that depending on the QTS' (between 0.26/0.29 with some Rx from crossover L) an F3 in the high 30's is possible. Add a modest room gain and you are in business.

I consider adding significant Rx un suitable as you trade un warranted losses in driver efficiencies for extension when electrical boost of 6 db and Q equal 2 with Keeles formulae can offer extension in a WaF friendly box.

frank23
01-04-2015, 02:23 AM
Here's a ( very ) handy online calculator for ( decibel > THD distortion conversions ) (http://www.sengpielaudio.com/calculator-thd.htm).

:)

I was actually looking for the rising distortion with a rising level. The distortion figures for the E145 are at 10W, and I wondered about the figures for 1W. But looking at this graph, I think one can assume the difference between the distortion for 1W and 10W to be roughly 10dB:

http://i200.photobucket.com/albums/aa253/frankvcp/2344a_dist.jpg (http://s200.photobucket.com/user/frankvcp/media/2344a_dist.jpg.html)

So that would mean the 150Hz distortion for the E145 at 1W would be about -55dB if every horizontal line represents 1dB for a full graph scale of 40dB. And -45dB at 10W.

The 1501AL does -65dB at 10W which is significantly lower. I still wonder whether the scale of the E145 graph is not 2dB/division so the E145 would come at -70dB. Wishfull thinking perhaps...

gibber
01-04-2015, 05:02 AM
I finally tried this today, after having tinkered with it on and off over the past few weeks.

I could see no improvement in lf extension when inserting a resistor. in fact extension suffered a little. The E145 was in a 4507 5cu 150l cabinet. I think I had it with all 4 ports open, but I was tinkering with that also, so I can't recall that exactly, might even have been closed :-)


Hi Frank, the change in Qts requires a re-alignment of the box for the new Q.

Assuming your measurement frequency is at (or a least near) the minimum impedance between those two reflex "humps", then the added series resistance will take away more power at that very point than it would anywhere else below 150 Hz or so (i.e. where impedance has its natural minimum before rising due to coil inductance).



Possibly another work around is to explore DB Keele 6th order paper on his web page and run the numbers.

My estimate is that depending on the QTS' (between 0.26/0.29 with some Rx from crossover L) an F3 in the high 30's is possible. Add a modest room gain and you are in business.

Hi Ian, Yes -- very good way to move forward, but requires your system to be active. Or stay passive as in the '70's EV implementation (also by Keele). But staying passive means to loop the complete signal through the (analog or digital) bass-EQ. EV recommended to use the tape monitor loop for their Interface XX series, but problem was the supplied analog equalizer killed mid/treble sound quality while doing that 6th-order bass EQ



I consider adding significant Rx un suitable as you trade un warranted losses in driver efficiencies for extension

May sound like the baby/bathwater thing, but that's perhaps the price when going passive. The series-R method is good for small changes only and makes a speaker less over-damped, optimizing step response a wee bit. A 2nd more powerful passive alternative would be to bend down the mid response early to "gain" bass extension. This comes with a penalty in phase response if passive/analog. For an E145 this would kill something like 10dB of its rated efficiency. In fact, Frank went a third and similarly powerful route by using an early X/O to his 2123 10" cones. But if passive, i wonder if sensitivity below 100 Hz still is on the good side of 90 dB that way?




One of the hallmarks of the traditional JBL transducers was their low Qts. Arguably the 124 and 136 went a tad overboard. ;)


Giskard, the E145 maybe, too. Market pressure must have been significant for E145, as Yamaha entered the musical instrument sound market with their brand-new JA3882 "K14x-killer" and claimed higher sensitivity than K140/145 had. Wording in the K- and E-series brochures you linked to at the beginning of this thread shows JBL's pride rgd that aspect at the turn from '70s to the '80s. E140/E145 have improved magnetic energy compared to the models they replaced. Hence Qts went down. The 3882B has an average of 0.14 on 8 samples taken from a US forces (must have hurt to see them buy Japanese) cinema here in Germany.

Ralph

more10
02-27-2020, 01:33 PM
WinISD can be used for calculating VAS. Which I did.

85932

gibber
03-01-2020, 09:00 AM
WinISD can be used for calculating VAS. Which I did.



The Vas you get is in line with what Giskard expected.
Maybe you took K145-8 values into WinISD?

K145 has Re of ca 9 ohms. It is a “12 Ohm“ driver.

But I would expect Vas results to be the same, also for K145-16 and the ultrarare K145-4

The wear of the doped paper surround has a much bigger effect than the coil mass differences between 4/8/12/16 ohms. I get values from below 30 to mid 40’s for Fs on the samples i measured over time

All the best, Ralph

more10
03-01-2020, 09:31 AM
Straight from the table. I see I forgot le, but le doesn't affect VAS. Green in WinISD is entered. Blue is calculated.

gibber
03-02-2020, 01:24 PM
Straight from the table. I see I forgot le, but le doesn't affect VAS. Green in WinISD is entered. Blue is calculated.

Sorry, my bad. You worked on E145, which only exists in 4/8/16 ohm versions to my knowledge. The Mmd shown in the table for the unit was taken over from K145. But E145 have a fabric double roll glued to a thicker paper than used in E145.

The wide range of Fs i noted for K145 may well have been the reason to go for fabric surround in E-series

Ralph

maxserg
03-07-2020, 03:58 PM
By the way is it still possible to find those clips for front mount? I would need for four k145...

rogerjulien
05-23-2020, 10:42 AM
I can put in some messurement of used E145 wich a friend, Oliver hoschibill, did last year.
The units where old and used but in good working condition.

Fs: 29
Re: 6
Qts: 0,2
Qes: 0,21
Qms: 3,34
MMs: 73g
Rms: 4,23
Cms: 0,000406m/N
Vas: 452
Bl: 19,9
ETA: 5,36
Lp@ 2,83V: 100,65

Maybe that is helpfull for someone.

I just purchased a pair of nearly new E145,
going to put them in a sealed 40 Liter enclosure.
Should give them a rolloff at about 100Hz with Qtc 0,7.
Trying to let them play up to 800-1kHz and fit my diy Ribbon for highs.
If that does not work I 'm in need for something else to play on top.
How far low can I tweak the 2425 with the 2344?

Liked the crispy detailed sound of the E145, but bass is not much like stated before.
So I will try them as a punchy lowmid driver and luckily I have some decent units to fit the lower end.

86746

Cabasse 55 for those who wonder.
86745

rwwear
05-27-2020, 02:43 PM
How would the E145 work in place of a 2231A in the 4343?

Earl K
05-27-2020, 04:37 PM
How would the E145 work in place of a 2231A in the 4343?


Poorly ( no matter if you EQed in the bass > you'd be left with a sense of loss ( no bass > no impact > no weight > no anchor to the sound ).

:)

rwwear
05-27-2020, 07:55 PM
Poorly ( no matter if you EQed in the bass > you'd be left with a sense of loss ( no bass > no impact > no weight > no anchor to the sound ).

:)

Thanks Earl. Is there a substitute that works well without the Alnico magnets?

Mr. Widget
05-27-2020, 09:33 PM
Is there a substitute that works well without the Alnico magnets?The recommended alternative is the 2235H. It was the driver that was developed after the 2231H ferrite replacement for the 2231A alnico driver.

The 2235H is a drop in replacement for the 2231A.


Widget

rwwear
05-28-2020, 08:10 AM
The recommended alternative is the 2235H. It was the driver that was developed after the 2231H ferrite replacement for the 2231A alnico driver.

The 2235H is a drop in replacement for the 2231A.


Widget

In your opinion, does the 2235H sound better? Do you think Alnicos are a detriment? with modern amps.

Here's a quote from Great Plains Audio.

"Alnico magnets, by their nature, are easy to degauss (demagnetize) with drive. They will not change with time and their dependence on temperature is really small – maybe 1% at 100 degrees Fahrenheit. Alnico stability and resistance to back EMF is really good. This is why they make very good sounding magnetic structures. Unfortunately, given a big enough pulse of magnetic energy, they will degauss by up to 3 dB. The sensitivity to degaussing is dependent on the specifics of the magnetic circuit and the length of the coil providing the field. Underhung woofers, midranges, tweeters, and compression drivers do not have sufficient back EMF fields to push the operating point of the structure below the knee. They are essentially stable regardless of input signal. The short-gap, long-coil speakers are the ones that have a problem. A woofer can take a hit of up to 3 dB, if a big enough hit of current takes place. 1.5 dB to 2 dB is more common. The effect does not get better or worse with time, it solely depends on how much current is driven through the coil. The more current, the more field. Once the field is bigger than a certain number, some amount of degaussing occurs. It is permanent (until externally recharged) and will only increase if a larger sustained current hit occurs. Therefore, if you have a qualifying alnico woofer and you have played it loudly, you have some degaussing. You can have the unit recharged, and it will be fine until you play it again. Exceed the critical level, and it will start degaussing again. If you never do, it won’t ever degauss. Most of these designs trace back to the 50’s and 60’s where 15 – 30 watt tube amps were the rule. They didn’t have the current capability to hurt anything. With the advent of big solid state amps, the current levels went up and the problem started to surface.
Most of the qualifying motors will lose 1 – 1.5 dB, unless they are pummeled. Some of the older 3″ motors with really short magnets will typically be around -3 dB down. They go really easily.
Great Plains Audio can regauss your alnico magnets, if they need it. Regaussing is included free when we replace diaphragms and cones." https://greatplainsaudio.com/great-plains-audio-announcements/alnico-magnets-degaussing-losing-magnetic-field/

JeffW
05-28-2020, 08:59 AM
Without commenting on the drivers themselves, here's a little piece (two, actually) on the magnets

http://www.audioheritage.org/vbulletin/showthread.php?4031-The-Great-Alnico-Ferrite-Debate

The Great Plains piece is copied from the second one, written by Greg Timbers. Not sure if Great Plains gave attribution.

rwwear
05-28-2020, 10:15 AM
Without commenting on the drivers themselves, here's a little piece (two, actually) on the magnets

http://www.audioheritage.org/vbulletin/showthread.php?4031-The-Great-Alnico-Ferrite-Debate

The Great Plains piece is copied from the second one, written by Greg Timbers. Not sure if Great Plains gave attribution.

Thanks Jeff. Very informative.

rwwear
05-28-2020, 07:22 PM
Without commenting on the drivers themselves, here's a little piece (two, actually) on the magnets

http://www.audioheritage.org/vbulletin/showthread.php?4031-The-Great-Alnico-Ferrite-Debate

The Great Plains piece is copied from the second one, written by Greg Timbers. Not sure if Great Plains gave attribution.

Does anyone have any info on reconing from a 2225H to 2235H?

Mr. Widget
05-28-2020, 07:49 PM
Does anyone have any info on reconing from a 2225H to 2235H?You need to find an authorized JBL reconer who has access to JBL C8R2235 recone kits. The 2225H basket is identical to the 2235H basket.


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rwwear
05-28-2020, 09:31 PM
You need to find an authorized JBL reconer who has access to JBL C8R2235 recone kits. The 2225H basket is identical to the 2235H basket.


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I saw a 2225H for sale that has been converted to a 2235H and wondered if it is kosher.

Mr. Widget
05-28-2020, 09:45 PM
I saw a 2225H for sale that has been converted to a 2235H and wondered if it is kosher.Could be perfect, but there are so many ways that it could be a pile of junk.

You'll need more info.


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Kay Pirinha
05-29-2020, 04:04 AM
I've got a pair of 2225H's reconed to 2235H's last year by a professional. Due to the stickers at the cones' back he used genuine C8R2235 kits. But even he obviously did a mistake, as the VC of one driver rubbed and scratched in the gap when it arrived to me. I've sent the unit back for repair, which he did, and after a week or so I got it back, then flawless.

What I what to say is that reconing appears to be a rather delicate and tedious job.

Best regards!

rwwear
05-29-2020, 08:24 AM
Could be perfect, but there are so many ways that it could be a pile of junk.

You'll need more info.


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What makes the recone to 2235 different from the 2225? Is it the voice coil?

Mr. Widget
05-29-2020, 08:42 AM
What makes the recone to 2235 different from the 2225? Is it the voice coil?The cone, the surround, the spider, and the fact that the 2235H has an added mass ring. I am not sure about the actual voice coil, they may be the same but are likely different as well. The only thing they share is the basket (made up of several parts... magnet, top plate, voice coil gap, blah blah) and the dust cap.

If you are not careful you will buy a non JBL cone kit installed in a JBL basket, or possibly an improperly installed JBL C8R2235 kit in the basket. You will need to work with an expert who you can trust.


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rwwear
05-29-2020, 12:06 PM
I've got a pair of 2225H's reconed to 2235H's last year by a professional. Due to the stickers at the cones' back he used genuine C8R2235 kits. But even he obviously did a mistake, as the VC of one driver rubbed and scratched in the gap when it arrived to me. I've sent the unit back for repair, which he did, and after a week or so I got it back, then flawless.

What I what to say is that reconing appears to be a rather delicate and tedious job.

Best regards!

The worst of it is removing the old gooey foam.

rwwear
05-29-2020, 12:11 PM
The cone, the surround, the spider, and the fact that the 2235H has an added mass ring. I am not sure about the actual voice coil, they may be the same but are likely different as well. The only thing they share is the basket (made up of several parts... magnet, top plate, voice coil gap, blah blah) and the dust cap.

If you are not careful you will buy a non JBL cone kit installed in a JBL basket, or possibly an improperly installed JBL CR2235 kit in the basket. You will need to work with an expert who you can trust.


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What do you think these guys? https://reconingspeakers.com/product/jbl-2235h-c8r2235-recone-kit/

Mr. Widget
05-29-2020, 12:26 PM
What do you think these guys? https://reconingspeakers.com/product/jbl-2235h-c8r2235-recone-kit/I have no experience with the company, but many on this forum have had good experiences with this company. I would trust them when they say they are selling you a genuine JBL product.

That said, technically they are not supposed to sell a recone kit directly to the public. I am not sure how they get around that. For years, JBL insisted that only factory trained technicians were allowed to buy and install JBL kits. JBL had this requirement to make sure their high quality drivers maintained their quality. These days, who knows.


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rwwear
05-29-2020, 12:45 PM
I have no experience with the company, but many on this forum have had good experiences with this company. I would trust them when they say they are selling you a genuine JBL product.

That said, technically they are not supposed to sell a recone kit directly to the public. I am not sure how they get around that. For years, JBL insisted that only factory trained technicians were allowed to buy and install JBL kits. JBL had this requirement to make sure their high quality drivers maintained their quality. These days, who knows.


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I had to email them for a price.

The original JBL C8R2235 recone kit is $219.00 each plus shipping and we have them in stock.

Mr. Widget
05-29-2020, 12:54 PM
To you and anyone interested in 2235H drivers, I would jump on this as JBL has been making virtually all of their recone kits NLA at an alarming rate. It would surprise me if these are still available in a year or two... or tomorrow.


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grumpy
05-29-2020, 03:26 PM
Also from the same site:


— We are an authorized JBL service center. We repair with JBL parts when available. JBL does not allow direct sales of recone kits. These kits are available for repair.
I -interpret- this to mean the quote was the price for a kit, you would then have to ship them your frame and have them install it for an additional fee.

I've been wrong before :)

Good time to get a recone done, regardless.

rwwear
05-29-2020, 05:52 PM
Also from the same site:


I -interpret- this to mean the quote was the price for a kit, you would then have to ship them your frame and have them install it for an additional fee.

I've been wrong before :)

Good time to get a recone done, regardless.


The original JBL C8R2235 recone kit is $219.00 each plus shipping and we have them in stock.

If you would like to place an order please let me know the quantity and your location for shipping. I will send you a PayPal invoice to complete the purchase.

Kind Regards,
Melissa

grumpy
05-29-2020, 06:39 PM
The original JBL C8R2235 recone kit is $219.00 each plus shipping and we have them in stock.

If you would like to place an order please let me know the quantity and your location for shipping. I will send you a PayPal invoice to complete the purchase.

Kind Regards,
Melissa

There you go. Perhaps Samsung isn’t interested in policing this anymore.

Check the kits out as thoroughly as you can before gluing anything... if there’s an issue you’ll want to be able to return it.

it -will- cause me to view used items claiming to be “factory recones” a bit more skeptically/critically.

zeljkor
05-29-2020, 11:43 PM
Quality of new factory recones, at least for legacy drivers, is so poor from my experience that I do not see reason for them to policy anything. Instead they need to start to first improve QC and also to start to produce anything instead making kits NLA. But to be honest they are not much better with availability in case of spare parts for Samsung microwave ovens :)



There you go. Perhaps Samsung isn’t interested in policing this anymore.

Check the kits out as thoroughly as you can before gluing anything... if there’s an issue you’ll want to be able to return it.

it -will- cause me to view used items claiming to be “factory recones” a bit more skeptically/critically.

rwwear
06-01-2020, 11:40 AM
Quality of new factory recones, at least for legacy drivers, is so poor from my experience that I do not see reason for them to policy anything. Instead they need to start to first improve QC and also to start to produce anything instead making kits NLA. But to be honest they are not much better with availability in case of spare parts for Samsung microwave ovens :)

Do you believe the aftermarket kits are better?

Mr. Widget
06-01-2020, 11:48 AM
Do you believe the aftermarket kits are better?They are even worse! :banghead:

Edgewound has hand assembled some aftermarket kits that he carefully installs, but in general the aftermarket kits are not recommended.

The problem with the JBL kits has been consistency. Some are fine and others not. I wouldn't be surprised if Samsung/Harman has stopped producing kits for legacy drivers so what is available are likely items that were left in the corner of one of their warehouses. When they are gone, that will probably be that.


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