https://www.eighteensound.it/en/resources/suggested-designs/
https://www.bcspeakers.com/resources/suggested-designs/
There are some suggested designs from B&C and 18sound.
https://www.bcspeakers.com/resources/suggested-designs/
There are some suggested designs from B&C and 18sound.
If you have not tried them the 2450Sl/2451SL are technically better drivers. Larger, damped back chamber. same Coherent wave phase plug and exit fitting the 2384. And JBL built in inductance control and a better magnet design in them then the new 2452/2453's as seen from they're tech sheets.
the phase plugs are not quite as short as the 2452/2453 though, for better or worse, depending on the horn.
Good luck with that one with your wife 🤔
by the way thenew 1.4inch coaxial frm B&C looks impressing and not too expensive for a 400/20K model
What is the benefit of a larger, damped back chamber? I am puzzled why JBL would choose to go backwards with their drivers. My viewpoint is that companies like JBL hire competent engineers, have vast institutional knowledge, and have moved forward the state of the art. So, I would trust the changes they make.
Cost cutting. Saving pennies, while getting away with performance that is still perceived to be plenty 'good enough' for most of the intended applications.
Then if the 'revised' driver ends up being slightly worse for those very few who chase the very best technical performance in more 'audiophile' applications (NOT where most of the money is made with compression drivers), so be it.
They reduced weight by 50% ?
Reduced manufacturing costs by more then that, moved production to China and Mexico.
The inductance control is missing, which is easily seen by the factory tech sheets for the 2452/3 vs the older models, saving another few steps in manufacturing, on a part that is critical in machining tolerances.
For the 2453 they integrated the diaphragm into the back cup, to be able to shrink it even more, and not being able to just change diaphragms anymore.
Yet the price stayed the same. Surely no other motivation then improved quality🙄
Surely shareholder profit can't be a motivation, as with just about any other industry today😱
There is no reason why the "world" outsourced all they're manufacturing to China, while quality dropped, prices stayed the same and increased, except for better quality of course 🙄
The good part for PA customers are reduced size and weight, which might also be a factor.
Look at the impedance curve below, from JBL's own testing. And compare it to the 2450H,2451 or 2450SL, and see for yourself..
Hi ra7,
JBL returned to the larger magnet structure and back chamber in the flagship 476: https://www.audioheritage.org/vbulletin/showthread.php?31247-2450SL-vs-2452SL.
There was/is also some difference where/how the AQUAPLAS was/is applied on the diaphragm: https://www.audioheritage.org/vbulletin/showthread.php?3450-2450-Dia&p=296511&viewfull=1#post296511.
You will be able to find some measurements there as well as in a rather large thread here: https://www.avsforum.com/threads/just-purchased-a-pair-of-jbl-4722n-speakers.1925586/.
Kindest regards,
M
There does not appear to be a clear answer. I had perused the https://www.audioheritage.org/ where most of the JBL knowledgeable people gather, but the posts are rather inconclusive. For example, after developing the smaller 2452 and even smaller 2453 (see Arez' reply);
JBL returned to the larger magnet structure and back chamber in the flagship 476: https://www.audioheritage.org/vbulletin/showthread.php?31247-2450SL-vs-2452SL.
There was/is also some difference where/how the AQUAPLAS was/is applied on the diaphragm: https://www.audioheritage.org/vbulletin/showthread.php?3450-2450-Dia&p=296511&viewfull=1#post296511.
You will be able to find some measurements there as well as in a rather large thread here: https://www.avsforum.com/threads/just-purchased-a-pair-of-jbl-4722n-speakers.1925586/.
Kindest regards,
M
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Horses for courses. The 476 driver was only intended for use in their big-$$ audiophile home systems, not mainstream PA. That's why they went 'back' to a superior (but heavier and more costly) solution, against the previous 2451-2452-2453 trend.
Wrt the long AVS thread on the JBL 4722 (which I use with Rythmik F18 subs) that @mefistofelez mentions, user notnyt measured several JBL CD's on the JBL 2384 waveguide. You can find the measurements, including distortion profiles earlier in the thread for each driver.
He summarized his listening experience as:
"Listening impressions from 2453H-SL vs 2452H+BeX4008.
The Be diaphragm is slightly more detailed. Barely, but the Be just sounds the most precise. My wife described it like a picture with higher contrast. Both sound great, very smooth and detailed. Better than the 2432H. The 2452H-SL and the 2453H-SL would be nearly impossible to distinguish. The 2453H-SL measures nice and flat without any EQ and sounds great without any electronics necessary as well. I'd take them over the D2430K as well, likely due to the 4" diaphragm and dead simple setup with super flat response. That said, they're closer in sound to the D2430K (post eq) than the 2452 with the Be diaphragm.
So, my order of preference so far. I have a 2431H and a 2435HPL on the way to test thanks to @wrager.
1) 2452H-SL + BeX4008
2) 2452H-SL / 2453H-SL
3) D2430K
4) 2432H
The largest jump in quality here is between 3 and 4. 2 and 3 are virtually indistinguishable after EQ. In reality, they're all very good, and the differences are very subtle."
I use digital crossovers room correction on my system, so it gives me pause to purchase anything further. Sure, notnyt's experience is subjective and we all have our subjective thoughts, but I am open to a something better... But what is measurably and audibly better assuming high resolution eq takes the frequency response out of the equation?
He summarized his listening experience as:
"Listening impressions from 2453H-SL vs 2452H+BeX4008.
The Be diaphragm is slightly more detailed. Barely, but the Be just sounds the most precise. My wife described it like a picture with higher contrast. Both sound great, very smooth and detailed. Better than the 2432H. The 2452H-SL and the 2453H-SL would be nearly impossible to distinguish. The 2453H-SL measures nice and flat without any EQ and sounds great without any electronics necessary as well. I'd take them over the D2430K as well, likely due to the 4" diaphragm and dead simple setup with super flat response. That said, they're closer in sound to the D2430K (post eq) than the 2452 with the Be diaphragm.
So, my order of preference so far. I have a 2431H and a 2435HPL on the way to test thanks to @wrager.
1) 2452H-SL + BeX4008
2) 2452H-SL / 2453H-SL
3) D2430K
4) 2432H
The largest jump in quality here is between 3 and 4. 2 and 3 are virtually indistinguishable after EQ. In reality, they're all very good, and the differences are very subtle."
I use digital crossovers room correction on my system, so it gives me pause to purchase anything further. Sure, notnyt's experience is subjective and we all have our subjective thoughts, but I am open to a something better... But what is measurably and audibly better assuming high resolution eq takes the frequency response out of the equation?
Hi marco_gea,
Kindest regards,
M
That would support the argument that the move towards 2452 - 2453 was due to a coast-cutting reasons and to due to improvement in magnet and/or phase plug design.
It is my understanding that apart form the mounting holes, the SL2450(SL) and the 2451 are identical structures.
Kindest regards,
M
@mefistofelez @Arez @marco_gea Seems like a nice story (old is gold) and in many industries, products are being engineered to be cheaper. I'm sure this is true about compression drivers. The question is whether the performance is affected measurably and audibly. Based on suggestions above, I spent a few minutes looking at the spec sheets of 2452 and 2450. At least from the impedance graphs, I see an improvement in the HF impedance rise of the 2452 relative to the 2450 or at least that they are even. So, I'm not sure where all the talk of "missing inductance control" comes from. I have not looked at distortion measurements yet.
2452: min 6 ohms, max 14 ohms.
2450: min 12 ohms, max > 20 ohms.
2452: min 6 ohms, max 14 ohms.
2450: min 12 ohms, max > 20 ohms.
^^This.
Cell phones went from chunky dumbell sized things to flip phones to light pieces of glass. Does that mean they are worse today than 30 years ago? No, that’s called progress.
I’m just playing devil’s advocate here. What I really think is that older drivers are just as good if you can get them but nothing wrong with newer ones either, and they tend to be lighter and broadly good quality.
Comparing a 8 ohm coil with half the Re, vs a 16 ohm diaphragm and draw conclusions?
Look at the curves and the rise in the last octave. Also you are comparing a uncoated TI diaphragm, to a Aquaplas coated one which has much less high frequency disturbances/resonances.
What surely is visible is that the 2452, has a more unlinear impedance, and a much sharper rise in the top octave, ie: lack of impedance control.
Also some unnesseceary resonances/impedance blips lower down. Which with all things equal points to increased clearances and added cavity resonances as the most likely culprit.
Measurably there is differences, audibly they have different phase plugs, so they don't match ideally to the same horns/waveguides, so very hard to compare on a fair basis. The magnet design was also changed.
It is also along the lines of what some of the most renowned JBL engineers have hinted at, and who would know better?
I don't advocate for 'old is gold', just audio has, compared to other fields of technology hardly moved for 50+ years.
Not said that new products are not good or else, just that cost cutting and short cuts in engineering/manufacturing does not lead to better products.
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Hi ra7,
I certainly do not know what CD you have, but based on the tone of your responses, it seems that your inquiry in post #1,004 was not genuine, and I regret having spent the time to provide you with references so that you could make your own independent decision.
Kindest regards,
M
Can you please point to the text where I made the assertion that you allege?
I certainly do not know what CD you have, but based on the tone of your responses, it seems that your inquiry in post #1,004 was not genuine, and I regret having spent the time to provide you with references so that you could make your own independent decision.
Kindest regards,
M
Agree to disagree.
So, how were you drawing the conclusions about worse performance because you pointed me to that same spec sheet?
We are looking at the same data and drawing different conclusions. The graphs are of different scale. If you blow up the 2450 and look at the same level detail, it may look different to you. My feeling is that there is not much in it and I don't see evidence of lack of inductance control.
Agree!
Who said this? I don't think JBL engineers will make such statements.
This I can get on board with! But reading the past few pages, there was a lot of worship of old, unobtainable TAD and similar drivers. The implication is that the engineers in the intervening time have done nothing and companies are just looking to make profit. As an engineer myself, I don't agree with this outlook. What I see in the products is improvements in size and weight that are important for the target market. The question is whether as audiophiles using these drivers those changes have a measurable and audible impact on our sound systems. I am yet to see evidence of worse performance. All I have heard are comments on diyaudio about how things might be with these drivers.
Sorry M, it was not directed at you specifically. I just wanted you to see the post. And apologies if my tone was not appropriate. I am trying to get engineers the credit they deserve 🙂
I have heard the TAD drivers at audio shows. Personally, I have owned a lot of JBL, except any of the Be diaphragms. Really, at this level, what matters more is the crossover and the rest of the system.
I'll also take the opportunity to thank @Arez @mefistofelez and @marco_gea for all the contributions to this site. I have learned a lot from you. Hope you guys don't mind the questioning.
As for Cell phones, progress and progress, the new ones die or shatter if you drop them to the floor. needs constant updating to work, have way worse batteries in many ways, and they don't really want them to last as your supposed to buy a new one every 1-2-3 years for the latest and 'greatest'.
Also remember you do it for the 'enviornment' these days, as the best thing one can do is constantly buy new stuff and throw it away at a ever increasing rate 🙄 🤣
I still remember the old Nokia 5110, survived punching in nails with, and dropping it from a rooftop, and they could even tolerate a dip in water 😱
Take LCD TV's then, i wonder how many 100 000s of Samsungs have ended up on the scrap heap, due to using cheap, undersized/underdimensioned capacitors by intent to sell more, and make em pop around warranty death.
Playing devils advocate is good sometimes as it promotes discussion.
Progress is good but not everything new is progress in every way.
And yes, weight and size savings are a big thing for large PA systems being moved around, so a important point for many mfgs.
Well aware that you are a proponent of active xo, and room correction. Your work is well enough known around here too i believe.
I do suspect your list of preference will not change a lot, the 2431/2435 has a phase plug design that is worse then the 245x line as documented well on audioheritage.org.
The D2430K does better on the M2 waveguide then the 2384, again notice the phase plug/ driver exit design.
While EQ is wonderful in some way it can not fix everything, and high quality is the key. Noisy minidsp 2x4s, that retails for 150$ at retailers with bad SM power supplies, is not the answer there.
As I'm sure you are well aware simple diode rectifiers are the absolutely worse offender in terms of THD in the electrical chain. Yet people wonder why they're compression drivers needs to be padded down due to noise artefacts.....
And active still feeds the whole chain of electrical noise to a driver in many circumstances, depending on design. Unlike the simple, old fashioned passive filters.
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Hi ra7,
Kindest regards,
M
O.K., thank you for the clarification. Sorry for my overreaction.
Maybe not the currently employed JBL engineers. 😀 But you can search for Gregg Timbers (former JBL engineer), for comments on different CDs.
Kindest regards,
M