JBL 2123H Sonic character and use in monitors?

[Jakob]

Hi,

I love my 250ti's and the 8" 108H mid. I'm thinking of implementing the same setup in my DIY speakers but with a 2123H. The DIY speakers will then consist of: ME150, 2123, 2307+2426 (or 2450/2451) and 2405.

The 2123H are not aquaplased as the 108H's. How are their sonic character? My main goal with the speaker are a decent frequency response and a very low listening fatigue factor also at rather high listening levels. Goes this hand in hand with the use of the 2123 or should I look at something else?

Why is the 2123 or something similar not used in the K2 series or Everest series?

Thank you for any input!

[Robh3606]

Why is the 2123 or something similar not used in the K2 series or Everest series?



There is simply no need too drop a 10 between the horn and the woofer. The drivers used are more than capable of covering that frequency range. Just adding complexity vs questionable added sonic benefit.

Rob:)

[Jakob]

Todays modern big monitors are setup the same way as the K2 9800 without a big cone mid.
Is it thanks to bigger horns with perhaps better loading in lower frequencies or progress in network technology that enables good sonic performance nevertheless? Improved driver performance?

Isn't it a good thing to have only one driver very suitable for the task, to cover a very important frequency band (where human ears are extremely sensitive), despite the fact that it adds complexity to network design etc...?

[4313B]

Improved driver performance?The designers consider the 1500AL and its derivatives to be light years better than their fifteen-inch predecessors, exhibiting exceptional resolution through the midrange and thus negating the need for a separate midrange transducer.

I've been told that JBL would have to come up with a four-inch coiled midrange transducer (think seriously modernized "2202AL" type) to be worthy of placement between a 1500AL and a 476MG or 476BE. "If I had it all to do over again I'd just run the 1500AL right up to the 476BE and call it done. It's that good." From personal experience I'd have to agree.

Not too long ago I heard that there was a wish to make an AL version of the new 1501FE used in the new 4365. I've been told that the 1501FE has remarkable performance, worthy of an AL version.

Todays modern big monitors are setup the same way as the K2 9800 without a big cone mid.While the 435BE/AL is a very nice driver it really isn't a 476MG/BE. It just isn't. It was the weakest link in the S9800. Note that it works extremely well on the smaller 1400 Array horn. The S9900 is the perfect evolution.

There is an underlying theme here... if it doesn't sport a 4-inch voice coil...

[JeffW]

I've been told that the 1501FE has remarkable performance, worthy of an AL version.
...

I sure wish I could land a second one, 10 months now.

[4313B]

I sure wish I could land a second one, 10 months now.Yeah, you'd think they were being made off world or something... Harman and Crown buyer/planners have a real problem getting parts from JBL Pro. There is a serious disconnect. It's like there is some kind of severe animosity between the various divisions. And of course JBL Pro won't sell directly, most of them don't even know what the Consumer parts are.

[Ian Mackenzie]

I heard the JBL 4465 at length at a hifi show in Melbourne lst week.

It had a number of sonic similarities to the 9900.




Yeah, you'd think they were being made off world or something... Harman and Crown buyer/planners have a real problem getting parts from JBL Pro. There is a serious disconnect. It's like there is some kind of severe animosity between the various divisions. And of course JBL Pro won't sell directly, most of them don't even know what the Consumer parts are.

[JeffW]

I just received one. I ordered two. If I get lucky I'll receive another one next year. I'm afraid to open the box though. It's probably broken in half.

Figures. I sure wish they would have sent me your one, but you've probably had it on order longer than the 11 months I have.

[ivica]

There is simply no need too drop a 10 between the horn and the woofer. The drivers used are more than capable of covering that frequency range. Just adding complexity vs questionable added sonic benefit.

Rob:)

but what about the "directivity" of 15"-cone driver. On axis, I believe it is perfect, but what about 45 deg off-axis. How 3" or 4" compression driver behaves under 800Hz (or may be 500Hz, because filters are not ideal), how large the excursion of its diaphragm in the region under 800Hz ???, and what would be the total cost...?

[4313B]

Figures. I sure wish they would have sent me your one, but you've probably had it on order longer than the 11 months I have.You wouldn't want it. The losers at their warehouse tossed it in a box with some peanuts and it got pretty busted up in transit.

It's kind of tragic that JBL thinks so little of their products. I'm coming around to thinking the same way.

[JeffW]

Sorry to hear about that, but I have been down that road with those buffoons.

And funny thing, the first 1501FE I got was just tossed in a box, no packing. Made it intact, a little scuffed.

Second 1501FE was encapsulated in expanding foam bags and the frame was busted.

Third, did I say third? 1501FE came with no packing, a little scuffed up but intact.

After your post, I called Jamie and she said my order had been filled, and was out for delivery today...but I never got an email. Well, here it shows up, the UPS driver cradling the sorriest looking box I've ever seen come off a truck. And for the record, Jamie has been an absolute trooper through all of this. She's in Consumer in CT (I think), Pro's in CA, and the things ship from GA. So she's just as incredulous as the rest of us trying to buy Pro thru Consumer, but she stuck with it.

Box, total amount of packing in the box, and maybe the only intact pair of 1501FEs that'll ever be seen in the wild.

Took damn near a year. The only reason I got a 1501FE in the first place was because Harman screwed up and sent me one instead of the pair of 1500FEs I ordered, so I pressed them for a second. And pressed them. And pressed them.

[4313B]

It goes to show you that if you ship enough drivers out eventually some will arrive in decent shape. A year is pretty consistent for delivery.

Jamie is awesome, always has been. I feel so sorry for her having to deal with stuff like this.

I'm really glad you finally have a workable pair. :yes: They should last a lifetime.

Their designer uses them in 4.2 cu ft tuned to 32 Hz in case you care.

[JeffW]

It goes to show you that if you ship enough drivers out eventually some will arrive in decent shape.

That's damn expensive buckshot they loadin'.


Jamie is awesome, always has been. I feel so sorry for her having to deal with stuff like this.

If the company had more like her, they wouldn't be in this pickle. She's a keeper.


Their designer uses them in 4.2 cu ft tuned to 32 Hz in case you care.

I care. A lot.

You're still young, here's hoping you get a workable pair.

[Robh3606]

but what about the "directivity" of 15"-cone driver. On axis, I believe it is perfect, but what about 45 deg off-axis. How 3" compression driver behaves under 800Hz, how large the excursion of its diaphragm in the region of 800Hz ???, and what would be the total cost...?

Hello ivica

We can see the system plots posted there certainly doesn't appear to be any serious issues. Here's a Link http://www.audioheritage.org/vbulletin/showthread.php?10639-K2-S9800

You can see a jog where the crossover point is in the DI curve and notch in the off axis FR but nothing all that terrible. Droping in a 10" driver is going to give you an additional point to match the DI and shift them both down and up. Seems that would be a good deal harder to get right.

As far as a 3" driver being used that low I am using Be 3" drivers in my Array clones with a 750Hz crossover point. They sound great with no issues I can hear.

Not sure what you mean about the total cost?

Rob:)

[4313B]

You can see a jog where the crossover point is in the DI curve and notch in the off axis FR but nothing all that terrible.It's quite good. JBL has the power response thing nailed. One either likes the result or they don't.

As far as a 3" driver being used that low I am using Be 3" drivers in my Array clones with a 750Hz crossover point. They sound great with no issues I can hear.Well that's the best part isn't it? You and I can sit here listening to how fantastic these loudspeakers sound while the rest of the world frets about theory. :)



"Shouldn't there be a midrange driver between the fifteen and the horn?"
"No, it doesn't need one. The fifteen is thoroughly capable."
"But I really want a midrange driver between the fifteen and the horn, the Internet says I do."
"Then put one in by all means. Whatever helps you sleep at night..."

[ivica]

Hello ivica

...............They sound great with no issues I can hear. ............

Rob:)

I think that statement is THE MOST IMPORTANT, because (neglecting from time to time some technical curiosity) we use our speaker to enjoy in the music that they reproduce (or make) and not to listen speakers "creation".

Concerning the price, well, that from my point of view, depends how much efforts has to be done in order to get the '(expect-able) amount' of pleasure.
For some of us 100$ is much, for the others 1000$ is much, to the thirds 10.000$ is much...., or the words "is much" can be exchanged with "not too much", but all in all, all of our speakers are king of technical, economical,..... etc. compromises.
I wonder what would be the price we have to pay for one technical solution, and on the other side "how much we lost in enjoyment "

I can not forget the sound of the drum that was reproduced from my friend's speaker (4345 clone), even all used parts are 'standard' for such speaker.
At that moment I had "visual experience" of the drum size, not only acoustical feeling of "deep" sound.

I have absolutely no idea what would be the cost of the mentioned "Array" clone pair and if they are not too expensive,
Rob's good experience with them, may be a good suggestion for the other members to start DIY projects, especially it
seems to me that they are not so large as mentioned 434x family.

[Ian Mackenzie]

ME150, 2123, 2307+2426 (or 2450/2451) and 2405.

Before this thread became another blog on the 1500 series drivers perhaps it might have paid to read the paper on evolution of studio monitors.

In that paper they explain "why" trying to mate a ME150 to a 2307 will sound like shit.

Too often we see a convergence on the driver wow factor thingy and not more broadly on systems integration. Heck, some projects with even the finest drivers never see the light of day because diy people could not make them work.:banghead:

In laymans terms a well integrated 2 or 2.5 way system will always sound more coherent than a 4 way system. But trying to find a listenable 2 way is like pulling hens teeth.

What does that mean?

The polar response of the woofer at the Xover point must match that of the horn or it will honk. In the case of the 15 inch woofer it generally agreed that 1K is the max crossover point before it becomes sub optimal in terms of cone break up. The polar pattern is 100 degrees at 1K. The 2307 is at best 80 degrees and below 1200 hertz its dogs breakfast. The longer 2312 fog horn sounds even more horrible crossed over at 800 hertz. The Altec Dulpex 604 were vomit to audiophile ears for the same reason.:banghead:.

The research in that paper gave rise to the 4430 - 4435 Bi radial monitors.

Its actually quite difficult to make horn that does not sound like a horn below 1500 hertz and the size of the horn becomes difficult. People then try and make the horn smaller and that makes matters much worst.

One afternoon I was sitting in Steve Schell's back yard down in Long Beach having an ale and Steve had a wonderful story to tell on what they tried to do with the VOT by making it smaller.:crying:

Steve's large straight sided mid range horns are among the best I have ever heard as are his drivers.;)

Back on planet earth suggest you try the 2344 bum horns on the ME150.:bouncy:

If you cant find a 2344 horn you will find in practise the 2123 + 2307+ 2308 crossed over 1.3 - 1.7 khertz will actually sound quite respectable...apparently.

[richluvsound]

[QUOTE=4313B;323437]
Well that's the best part isn't it? You and I can sit here listening to how fantastic these loudspeakers sound while the rest of the world frets about theory. :)



Ignorance is bliss :D

[4313B]

Before this thread became another blog on the 1500 series drivers perhaps it might have paid to read the paper on evolution of studio monitors.Yeah, I was just reminded about the whole fifteen-inch two-way thing and a remark one JBL engineer made with respect to the 1500 series drivers. "The 1500AL is the first JBL fifteen that isn't geometrically challenged. It has the same perfect pitch that the LE14 and 2245 have."

Indeed, we all survived through the 4331, 4333, L300 and 4430 well enough (I certainly enjoyed my various pairs) but the 2231 and 2235 arguably benefited from having a midrange driver handling the 300 Hz to 1.2 kHz region as per systems such as the 4341, 4343, 4344, 4345, 4355.

But trying to find a listenable 2 way is like pulling hens teeth.Tannoy DC's can be pretty listenable.

The fact remains though that some people will always feel that there should be some kind of midrange driver between the woofers and the horns in systems like the S9800, S9900 and E2. I know a few that are pretty adamant about it.

[ivica]

.

Before this thread became another blog on the 1500 series drivers perhaps it might have paid to read the paper on evolution of studio monitors.

In that paper they explain "why" trying to mate a ME150 to a 2307 will sound like shit.

.

do you think ?,
http://www.jblpro.com/pub/technote/tn_v3n01.pdf

or something else?

[Ian Mackenzie]

Sorry it was earlier.

This is a really excellent paper

http://www.audioheritage.org/vbulletin/showthread.php?7852-Improvements-in-Monitor-Loudspeaker-Systems&p=76021#post76021



But trying to find a listenable 2 way is like pulling hens teeth


I was refering to horn based systems where the rational historically was to have the horn run down to 500 or 800 hertz like the model 19 Altec.

Back to the point. On listening to a 4331 and comparing it to a 4430 there is no comparison. I agree the woofers are no match for the 1500AL but the compromises in 4430 work together.

Back then the 2231A and the 2235H were regarded as extended LF drivers and its logical that a dedicated midrange is required.

While in theory a pure piston range system can only be a multi way driver setup the compromise there is a the diffuse nature of the system imaging capabilities.

Some listerners value imaging above absolute accuracy while other will favour accuracy above all else.

From my own point of view the former is mythical in that its only ever as good as the recording allows.

I have heard all the recent two way systems incl the 9800, 66000, 9900, the 4600 and the new 4365 which I like.

They all have higher resolution than the older 43XX stuff thanks to recent driver technology.

They also convey the impression of being more forgiving of recordings than the old 43XX systems.

I think this is because these newer systems are easier to listen to because those older designs chopped up the presentation into distinct ranges and that forced you to listen and focus in on each driver. (particularly if you have the grill covers off) The harder you listen the more bad stuff you hear on a recording. The brain then has to process all that and put the presentation back together. There are a lot less timing errors on the new stuff and also helps transients and resolving power.

The old 43XX can become tiring after a while as we know but they are fun all the same.

[Robh3606]

Here's a little gem we have in the Library that compares the 4330 4333 and 4343. It's an interesting read.

http://www.lansingheritage.org/html/jbl/reference/technical/monitoring.htm

And also this that has comparisons to the 4430 and the Urie's

http://www.audioheritage.org/vbulletin/showthread.php?4408-JBL-Technical-Notes-Volume-1-Number-15

Rob:)

[Robh3606]

Rob's good experience with them, may be a good suggestion for the other members to start DIY projects, especially it seems to me that they are not so large as mentioned 434x family.

Hello ivica

I would encourage people to build both actually. It really depends on what exactly you are looking for. The problem about building the Arrays is availability of the parts. You could purchase a SAM1HF for the top end and try to scrounge the woofers. You could probably get away with LE-14H's in a pinch.

http://www.jblsynthesis.com/Products/Details/103

As far as the 434x family is concerned parts are much more easy to get with the exception of the 2121 or 2122. 2123 are on E-Bay all the time. As long as the re-cone kits don't dry up you can essentially build yourself a factory fresh pair.

Bottom line is either one is a damn fine speaker in their own right. Clasic JBL sound 4344, more refined build the Arrays. My favorite are the Arrays but I won't be getting rid of the 4344 any time soon. Here's photo of my clones and as you can see they take up about the same footprint in a room.

Rob:)

[ivica]

Hello ivica

I would encourage people to build both actually. It really depends on what exactly you are looking for. The problem about building the Arrays is availability of the parts. You could purchase a SAM1HF for the top end and try to scrounge the woofers. You could probably get away with LE-14H's in a pinch.

http://www.jblsynthesis.com/Products/Details/103

As far as the 434x family is concerned parts are much more easy to get with the exception of the 2121 or 2122. 2123 are on E-Bay all the time. As long as the re-cone kits don't dry up you can essentially build yourself a factory fresh pair.

Bottom line is either one is a damn fine speaker in their own right. Clasic JBL sound 4344, more refined build the Arrays. My favorite are the Arrays but I won't be getting rid of the 4344 any time soon. Here's photo of my clones and as you can see they take up about the same footprint in a room.

Rob:)

O, what a nice pair: old and new "school", such as Grandfather and Grandson "walking together" on Sunday sunny morning.

I only wonder why 077 / 2405 is on side of 242x, and not 'on top'.
Rob, is there any 'objective' reason for that?

[DavidF]

" ..."I was refering to horn based systems where the rational historically was to have the horn run down to 500 or 800 hertz like the model 19 Altec..."



Perhaps better to use the A7 et al or the 846/Valencia era of designs as examples. I think the Altec engineers stepped out of their box and came back with a better idea for the 811 horn in the Model 19. The high side filter reponse was equalized and not taken down as low.

[4313B]

They also convey the impression of being more forgiving of recordings than the old 43XX systems.I agree.