JBL 2214H Build....L100T or 4425 ?

[RMC]

Bedrock,

Other good reasons to go with the L100T in your case.

Your intended use fits more with an Hi-Fi application than control monitoring.

Going with the 3-way you'll enjoy lower distortion in the high range since a dome has less distortion than the horn for comparable sound level.

Another benefit of the 3-way is you'll get increased mid sound dispersion due to the 5" cone mid compared to the 12" (at least up to the 1.2 khz crossover). A larger size woofer starts getting more directional (limited dispersion) way before a smaller mid.

In the 4425, the 2214 is practically used up to the limit of directivity with close to Di 10 db! In a studio control room where the sound is for and directed at the recording engineer this is more acceptable. Somewhat less desirable for a home environment.

The 5" mid will start progressively, as frequency goes up, getting more directional at approx. 3 khz which is better than the 2214. (The velocity of sound, used in the calculation, can vary a little depending if measured at sea level or not and room temperature). So the 5" cone will cover a larger bandwidth having a wider dispersion vs the 2214.

Richard

[Ian Mackenzie]

Zactly

[bedrock602]

Bedrock,

Other good reasons to go with the L100T in your case.

Your intended use fits more with an Hi-Fi application than control monitoring.

Going with the 3-way you'll enjoy lower distortion in the high range since a dome has less distortion than the horn for comparable sound level.

Another benefit of the 3-way is you'll get increased mid sound dispersion due to the 5" cone mid compared to the 12" (at least up to the 1.2 khz crossover). A larger size woofer starts getting more directional (limited dispersion) way before a smaller mid.

In the 4425, the 2214 is practically used up to the limit of directivity with close to Di 10 db! In a studio control room where the sound is for and directed at the recording engineer this is more acceptable. Somewhat less desirable for a home environment.

The 5" mid will start getting more directional at approx. 3 khz which is better than the 2214. (The velocity of sound, used in the calculation, can vary a little depending if measured at sea level or not and room temperature). So the 5" cone will cover a larger bandwidth having a wider dispersion vs the 2214.

Richard

Thank you Richard, I always appreciate your expertise

[Robh3606]

Enjoy your build. Give this a read. It's informative and compares horn vs all dynamic drivers in the smaller monitors. You can sub L100t for 4412 in the comparisons. Very similar systems.

I would try both but that's me. Make sure you match the driver spacing baffle placement and width. Also recess the tweeter so it's flush mounted.

The crossover was designed with that spacing and placement. If you don't flush mount you will get ripples in the tweeter response.

Rob



https://www.audioheritage.org/vbulle...me-1-Number-15

[bedrock602]

Enjoy your build. Give this a read. It's informative and compares horn vs all dynamic drivers in the smaller monitors. You can sub L100t for 4412 in the comparisons. Very similar systems.

I would try both but that's me. Make sure you match the driver spacing baffle placement and width. Also recess the tweeter so it's flush mounted.

The crossover was designed with that spacing and placement. If you don't flush mount you will get ripples in the tweeter response.

Rob

https://www.audioheritage.org/vbulle...me-1-Number-15

Thank you Rob for the suggestion and link. Will give it a read. The Urei driver looks interesting. If I remember correctly, it is built on the 2214H

[Robh3606]

Your welcome!

Yes it was essentially a 4425 using a coaxial driver arrangement.

Rob

[Ian Mackenzie]

Your welcome!

Yes it was essentially a 4425 using a coaxial driver arrangement.

Rob

Hi Rob,

I don't think digging into technical information is helpful here in this discussion

Firstly the technicalities of one design versus another are not a reliable indicator of a particular listeners enjoyment.

There's a lot more to it.

Tech Docs
Looking at that these tech notes they are for professional applications. Not for home use in a room with flat walls and sparse furnishings.

So is that information really relevant? Does this listener have a recording studio at home?

Reading JBLs tech docs is like Mr Widgets reference to 'Site Bias". Just reading that information may convince you it's better. But in a double blind test in your own room which loudspeaker will you prefer? (not in Harman's acoustically treated listening room).

John Nebel and I compared both the 4343 and the 4435 in his listening room. The subjective outcome was it wasn't clear cut by any means.

This is a very good insight from Andrew Jones

https://youtu.be/4t-wdP4gISI?si=JFnfzvlPQ6uGRwsz

The Reality Check - building a loudspeaker
The thing is even if a loudspeaker build is cloned or designed according the a tech doc it may not subjectively be as enjoyable as a less technically perfect or a different design. A successful consumer system is often the result of empirical trial and error, listening, measurements, trial and error, listening.

If in the listening it doesn't Translate to how you as an individual recalled it sounded or how you believe it should sound its a Fail.

The sound speaker builder. The limitations
Why do loudspeaker builders scratch their heads wondering why a technically perfect (in their mind) system isn't doing it for them?

I recall the frustration of loudspeaker builder who went out and bought aftermarket beryllium diaphragms thinking they were the holly grail. But in the initial listening they fell short of expectations.

This is because they wanted the end result in a thread on the forum.

They didn't do any comparisons, trial and error because they were / are either lazy or didn't think that they had to. They were too reliant on what they wanted to believe (unfortunately).

Unfortunately it doesn't work that way. Greg Timber's himself called this out in an interview.

You have to be open minded at the very start before you get deep in the detail.

With all the JBL Consumer systems JBL hasn't told you they spent considerable time and effort with prototypes, voicing the L100T and every other system so that it did deliver an enjoyable subjective result. Otherwise they wouldn't sell anything. Dooooooo?

He has to put the work in and listen for himself in his own room rather than form a judgement based on adhoc comments.

[Robh3606]

Hello Ian

"John Nebel and I compared both the 4343 and the 4435 in his listening room. The subjective outcome was it wasn't clear cut by any means."


"He has to put the work in and listen for himself in his own room rather than form a judgement based on adhoc comments."


I guess you missed i said this


"I would try both but that's me."

And JBL's tech sheets I very much respect, many could be an industry reference at the time they were published. They offer a lot of information and references for further evaluation.

Typically the references are AES peer reviewed and published papers.

As far as reading a tech sheet adding bias??? These are basically factual with measurements and tech references for back up.

If you see that as adding significant bias fine. I don't, agree to disagree.



Rob

[Ian Mackenzie]

why?

Ian could very well have some useful information to impart to you. And, because he offered!
Will it hurt you to try?

I have all of the components for the L100T but am intrigued by the 2-way 4425 studio monitors which use the same woofer.

Before I build the enclosures and invest in the horns, drivers and crossovers for the 4425, I'm wondering what would be the benefits or drawbacks to either of these models?

I will be using them in a 9x12 dedicated listening room with lower wattage tube and solid state amplifiers at low to moderate listening levels of jazz & classical.

Enjoy your build. Give this a read. It's informative and compares horn vs all dynamic drivers in the smaller monitors. You can sub L100t for 4412 in the comparisons. Very similar systems.

I would try both but that's me. Make sure you match the driver spacing baffle placement and width. Also recess the tweeter so it's flush mounted.

The crossover was designed with that spacing and placement. If you don't flush mount you will get ripples in the tweeter response.

Rob



https://www.audioheritage.org/vbulle...me-1-Number-15

Hi Rob,

Now that l have the bandwidth to load a page yes l read the attachment and re read the entire thread. We agree to disagree on the relevance to the end application. See below.

Others may benefit from my thoughts below on where the simpler 4425/4425mk11 maybe a preferred diy build over the L100T.

The facts:

https://jblpro.com/en/site_elements/4425-information

https://audio-database.com/JBL/speaker/4425mkii-e.html

My understanding was original poster refers to a dedicated 9x12 home listening room listening to classical and jazz with low wattage amps. Power rating unknown.

(There is a long thread on a 4425mk11 build somewhere).

It’s an about face on my earlier post but the 4425 with its coherence & wide dispersion is an advantage in a dedicated listening room with classical and jazz genres. ( this is assuming side wall, rear wall and floor treatments for those wide angle bi radial horns).

Why l bring this up is that the context of that tech note quoted below is for professional mixing environments where control rooms and other post production facilities have treated acoustics. The backbone of the JBL bi radical systems design theory is uniform directivity off axis into a uniformly treated room. Not a bare room with flat walls, floor and ceiling. You can’t mix with first reflections and bounce of the ceiling and rear wall. To obtain an accurate mixing translation the room and the monitor requirements are actually quite critical.

In the consumer listening space JBL use the term controlled directivity when describing horns used for consumer use. They are typically narrower than the 4425 100 x 100 directivity and closer to 90 x 60, 80 x 60 degrees depending on the system. They can also benefit from corner placement so that side walls have less interference with first reflections. Referring to owner manual and it’s self explanatory.

People can believe and do what they like of course. I don’t dwell on that because they live with their own situation and out of sight.

The 4425 is a relatively simple loudspeaker system which benefits from adding your own diy flavours into the listening mix. That is why some of use are in this hobby after all.

I’ve personally had good results with the larger 4430 bi radical horn on jazz genres in terms of the sound stage and coherence in a modest but untreated listening room. Rob and l worked out the crossover and EQ for the larger bi radial horn 20 years ago. The bi radial horn projects a warmth that works well on brass instruments. But it lacks absolute resolving power in the upper octaves. I am not sure the 035 titanium tweeter is any better. It’s not an Array horn or a beryllium driver though. I used a Pass Aleph diy clone power amp. I think that really lifted the system above its weight. single ended class A amplifiers have a subtle 2nd harmonic warmth that can wash over some of the more irritating system errors while also being very transparent.

Improvements are possible with advanced driver designs and diaphragms. In the Voice Coil industry journal Vance Dickason tests a Radian 1” inch compression driver with a beryllium diaphragm. See link below . The aluminium diaphragm is also very good.

https://audioxpress.com/article/voic...ression-driver

This gives the 4425/4430/4435 traction for genuine improvement in the compression driver. In other areas Greg Timber’s made a better job of the 4425mk11 passive crossover. The earlier 4430/4435 network was designed by David Smith. These earlier networks had a high impedance causing ripple in the crossover region as a result of a compromise in the exponential section of the horn throat.

The 4425mk11 used a 175 nd driver which was probably better than the driver used in the 4425.

The larger 4430/4435 bi radial horn used a bolt on driver flange which allows alternative compression drivers.

Another avenue for performance gains comes with a bi amp solution with a low wattage valve amp on the horn and the SS amp on the woofer. I worked on an active crossover solution for a user in the UK a while ago. Being able to blend a particular amp on the horn and the woofer offers advantages for the savvy audio amateur aiming for audio nirvana. A powered sub could also be used to limit the load on the main amplifier driving the 4425.

The jfet active crossover kit over on Diyaudio.com can be set up for what l have outlined above.

The 2214H is a fast woofer according to Greg Timbers so that’s not much to be done there. Bass reflex tuning can be customised according to your enclosure location in the room.

Collectively these diy approaches may provide an intriguing journey inching closer to perfection than otherwise possible with the L100T.



************************************************** *******************

JBL tech note posted by Rob. As can be clearly read the audience of that tech note are pro mixing engineers in broadcast environments. Are you monitoring at home with Sonar Works in a bedroom covered in acoustic treatments? I rest my case.

“Which Monitor to Choose? There are no easy answers here. We recommend that the prospective user arrange an extended monitoring ses- sion with each basic design, carefully evaluating subjective performance with a wide variety of program material. Both current designs will handle almost any kind of program
material in stride. In general, the Time Align design may exhibit a little more "up front" character than the Bi-Radial, and this might favor it, in some engineers' views, for pop or rock applications. On the other hand, the smooth power response of the Bi-Radial design will require less third- octave equalization in the typical control room environment for adapting to a given house curve. Some engineers sub- jectively describe the imaging of the Time Align as existing in front of the enclosures, while the Bi-Radials seem to place the image in perspective behind the plane of the enclosures.

Monitors with Compression Drivers:
The UREI 809A and JBL 4425 represent a scaling down of the superlative performance offered by the large format monitors, and they are intended largely for smaller control rooms and so-called "semi-pro" applications where the larger models cannot be accommodated. Their design characteristics are listed below:
* Flat axial response extending to 18 kHz, with optimum low-frequency performance in a wall-mounted position.
* Smooth power response.
* Smooth phase (time domain) response.
* Accurate stereo imaging.
* System ruggedness at high frequencies, due to use of a compression driver.
Figure 12: UREI 809 On-axis response (1 W, 1 meter)
2= mounting; impedance.
Figure 13: Beamwidth (Horizontal and Vertical)
vs. Frequency, UREI 809
Figure 14: JBL 4425 On-axis response
(1 W at 1 meter) and Impedance.
Figure 15: JBL 4425

4312A and 809A may also be recommended here, inasmuch as they can be operated at high levels, making it easier to spot problems such as noise or distortion.
* Remote recording applications: We recommend either the 4410, 4412, or the 809A because of their smooth, extended low-distortion response. This facilitates making critical decisions both in balance and critical stereo image placement. If size is a constraint, the 4408 may be used.
* Audio-visual applications: We recommend the Control 1 for smaller scale applications, and either the 809A or 4312A for larger scale applications. All three of these will produce excellent speech articulation.”

[Robh3606]

Hello Ian

Wait a minute!

"JBL tech note posted by Rob. As can be clearly read the audience of that tech note are pro mixing engineers in broadcast environments. Are you monitoring at home with Sonar Works in a bedroom covered in acoustic treatments? I rest my case."

You rest your case and reference reviews from Home & Studio Recording, August 1986.

Who's their target audience??

They compare the 4225 vs the Urie 809

Just like my Techsheet

"Monitors with Compression Drivers:
The UREI 809A and JBL 4425 represent a scaling down of the superlative performance offered by the large format monitors, and they are intended largely for smaller control rooms and so-called "semi-pro" applications where the larger models cannot be accommodated. Their design characteristics are listed below:
* Flat axial response extending to 18 kHz, with optimum low-frequency performance in a wall-mounted position.
* Smooth power response.
* Smooth phase (time domain) response.
* Accurate stereo imaging.
* System ruggedness at high frequencies, due to use of a compression driver.
Figure 12: UREI 809 On-axis response (1 W, 1 meter)
2= mounting; impedance.
Figure 13: Beamwidth (Horizontal and Vertical)
vs. Frequency, UREI 809
Figure 14: JBL 4425 On-axis response
(1 W at 1 meter) and Impedance.
Figure 15: JBL 4425"

And yet the Techsheet is not appropriate???

You are a piece of work!!! LOL

Rob

[Ian Mackenzie]

Hello Ian

Wait a minute!

"JBL tech note posted by Rob. As can be clearly read the audience of that tech note are pro mixing engineers in broadcast environments. Are you monitoring at home with Sonar Works in a bedroom covered in acoustic treatments? I rest my case."

You rest your case and reference reviews from Home & Studio Recording, August 1986.

Who's their target audience??

They compare the 4225 vs the Urie 809

Just like my Techsheet

"Monitors with Compression Drivers:
The UREI 809A and JBL 4425 represent a scaling down of the superlative performance offered by the large format monitors, and they are intended largely for smaller control rooms and so-called "semi-pro" applications where the larger models cannot be accommodated. Their design characteristics are listed below:
* Flat axial response extending to 18 kHz, with optimum low-frequency performance in a wall-mounted position.
* Smooth power response.
* Smooth phase (time domain) response.
* Accurate stereo imaging.
* System ruggedness at high frequencies, due to use of a compression driver.
Figure 12: UREI 809 On-axis response (1 W, 1 meter)
2= mounting; impedance.
Figure 13: Beamwidth (Horizontal and Vertical)
vs. Frequency, UREI 809
Figure 14: JBL 4425 On-axis response
(1 W at 1 meter) and Impedance.
Figure 15: JBL 4425"

And yet the Techsheet is not appropriate???

You are a piece of work!!! LOL

Rob

Ah you found a way to save grace…excellent…Lol

A piece of work? Apparently…..in the eyes of some….but l got a rise out of you didn’t l ..Lol.

It’s all a matter of an individuals perspective when looking at a complex topic like audio.

We are all right and we are all wrong depending on how you look at it.

Of course none of this would occur in a two way conversation which makes it a black hole on time taken to write up a response. It’s so primitive when you think about it but there is a funny side to it.

‘Oh your thread bashing now’. Some people loose it over nothing. I’m just having fun.
I just took the discussion up a notch to make a point. You know rub it in……Lol.

Hey, l was out listening to a band on Sat night standing right in front of the group.
The sound of the cymbals was so enlightening. Metallic shimmers that were so clear. Why can’t we get that at home? I’ve been pondering Todd’s Heil work and l must grab a pair.

[DerekTheGreat]

...Hey, l was out listening to a band on Sat night standing right in front of the group.
The sound of the cymbals was so enlightening. Metallic shimmers that were so clear. Why can’t we get that at home?...

The 801C driver found in the 81xC series is as close as I've gotten to that shimmer. I haven't heard anything else that makes a cymbal sound like a cymbal should, as well as reproducing the liveliness/excitement of the entire drum kit. The 811C's I've got paired with the M&K MX350THX subs don't make the midbass magic that the 813C's + 2245's do, but considering how much smaller their foot print is, it could be close enough for some. They at least still have that shimmer and beautiful midrange. I can also tell that the gear I've got driving the 813C's is much better than what is driving the 811C's. Also, as much as I want a pair of 809's to complete my UREI collection, their sensitivity (91dB) is a bummer compared to the 811C (97dB). Therefore, the 811C would be a better choice for low watt amplification.

From Ken's review:
"
...The first thing to strike home is the laid back, smoother subjective response of the 4425 when compared to the strident aggression of the Urei. The high frequencies in particular are more open than with the Urei and the bass is more forward, but it somehow lacks the attack and that uncanny impression of presence and loudness which characterise the Urei sound. Also sadly missing is that imaging accuracy...
"

I don't know that I'd call the UREI's aggressive, once properly tuned to the room and your tastes. I do not have mine set flat EQ wise. But yes, that attack, accuracy and pinpoint image give the sound this immediacy that has rendered all my other speakers muddy or muffled by comparison. A time aligned coax driver is where it's at for me.

[Ian Mackenzie]

Hello Ian

Wait a minute!

"JBL tech note posted by Rob. As can be clearly read the audience of that tech note are pro mixing engineers in broadcast environments. Are you monitoring at home with Sonar Works in a bedroom covered in acoustic treatments? I rest my case."

You rest your case and reference reviews from Home & Studio Recording, August 1986.

Who's their target audience??

They compare the 4225 vs the Urie 809

Just like my Techsheet

"Monitors with Compression Drivers:
The UREI 809A and JBL 4425 represent a scaling down of the superlative performance offered by the large format monitors, and they are intended largely for smaller control rooms and so-called "semi-pro" applications where the larger models cannot be accommodated. Their design characteristics are listed below:
* Flat axial response extending to 18 kHz, with optimum low-frequency performance in a wall-mounted position.
* Smooth power response.
* Smooth phase (time domain) response.
* Accurate stereo imaging.
* System ruggedness at high frequencies, due to use of a compression driver.
Figure 12: UREI 809 On-axis response (1 W, 1 meter)
2= mounting; impedance.
Figure 13: Beamwidth (Horizontal and Vertical)
vs. Frequency, UREI 809
Figure 14: JBL 4425 On-axis response
(1 W at 1 meter) and Impedance.
Figure 15: JBL 4425"

And yet the Techsheet is not appropriate???

You are a piece of work!!! LOL

Rob

Wait a minute 2.

Yes it’s a technical comparison now the 809 has entered the discussion.

I’m assuming the application around here is home music reproduction.

But if you have time please read each review of both the 4425 and the 809. Each review is by the same reviewer with both the full subjective (from an engineering & mixing perspective) and technical reviews of both the 4425 and the 809

The reviewer concluded the 809 is the superior monitor.

Now tell me and the rest of the planet why you believe in your own words figure 12, 13, 14 and 15 are so important to you??? Get up in your soap box and holler, worship and cut a fart is you feel like it.

I think you keep hinging on that because you personally believe those graphs paint a picture of it being better in some way.

I agree in a technical A/B if that’s the only criteria it might polarise a subjective assessment. But Robert, there are a myriad of reasons why measurements alone don’t add up to one listening preference over another. In this case is a pro mixing situation. Despite all JBL technical marketing blurb the Urei 809 with the same compression driver and a technically inferior horn (according to JBL) is preferred. The review measurements don’t depict one subjectively better than the other even if you think they do.

That of course is why the reviewer did a subjective assessment of both. Dooooooo.

The situation would be different again in a 9 x 12 room sitting mid field, not at a mixing console.

What l am saying is when you drill down into it and then lay a perspective on it the outcomes don’t appear logical. It’s in a sense irrational . Just because is looks that way doesn’t necessarily make it so. The truth is in the listening. It always was and it always will be.


https://www.muzines.co.uk/articles/m...jbl-4425/12852

https://www.muzines.co.uk/articles/m...urei-809/12827

I’ve attached your precious graphs too.

To bedrock

Quote Originally Posted by Ian Mackenzie View Post
He is far better off experimenting with a prototype build before determining which way to go.
JBL has already done that.

With a wider perspective after reading all my posts fully and an open mind you will garner my point. Don’t criticise what you don’t understand.

The short response is every JBL system and any well engineered loudspeaker that is somehow different from another is voiced differently. If it’s a specific application it will be voiced for that end use. To understand what voicing is this look at my attachment of an interview l posted previously with Andrew Jones and Steve Gutenberg who lays it out in common language everyone can appreciate. It’s basically Pandora’s box.

Andrew Jones is one of the most respected senior loudspeaker designers on the planet. In the interview he explains complex concepts in a way that is easy to grasp. This helps audiophiles or loudspeaker builders appreciate why listening differences exist that are not at all easily quantified with conventional published measurements. He covers a lot of space around rooms too. So it’s a wise read that will save many a lot of over thinking.

[Ian Mackenzie]

4425 review

See attachment for the measurements
Ken Dibble concludes this short series with a review of the JBL 4425 and compares the results with the Urei 809 reviewed last month.


Click image for larger view

Last month we discussed the country cousin relationship between these two West Coast studio monitor loudspeaker systems, set out the tests and the criteria to be applied, and reviewed Urei's new baby monitor, the 809. This month, it's the turn of JBL's baby: the 4425.


JBL4425


General Specification
Drive unit compliment
Single 2214 30cm lo/mid cone driver with 2342 bi-radial constant directivity HF horn and 2416 titanium diaphragm compression drive unit.

Crossover
Internal passive 2-way, 12dB/oct, 1.2kHz.

User Controls
Mid-level, HF level.

Cabinet loading
Direct radiating 54Ltr tuned reflex.

Impedance
8Ω nominal, 6Ω minimum.

Fundamental Resonance
34Hz

Termination
Screw terminals/4mm sockets

Power Rating
200W with band limited pink noise to IEC-268:1 or 1 kW 10mS peak unclipped.

Sensitivity
91dB for 1 W at 1m.

Dispersion Angle
100° x 100° nominal.

Dimensions
635mm high x 406mm wide x 310mm deep (375mm deep to include horn flare).

Weight
26kg

Finish
Oiled walnut cabinet with slate grey horn panel and dark blue fabric grille.

Price
£937.25 each suggested retail, including VAT.


Design Concepts and Presentation


Like the Urei 809, the 4425 also represents an attempt to provide a small but highly specified studio monitor based on the success story of a larger system. In the case of the 4435, it is derived from the JBL 4430 and 4435, but employs scaled down components. The system is intended for use in smaller control rooms and in other demanding audio production applications. Smooth accurate frequency response, flat power response and high power handling, combined with constant directional characteristics are the design objectives and as with the Urei, the 4425 also comes as left and right handed versions to maximise accurate imaging.

In total contrast to the Urei however, the 4425 is finished to a very high standard, with oiled walnut veneer to the cabinet sides, smart slate grey top panel carrying the horn and crossover control panel and blue stretch fabric covered detachable grille. Even the front rim of the drive unit chassis is black painted and finished to provide that little sparkle when the grille is removed. It is an altogether superbly presented and finished loudspeaker, quite in keeping with the long held traditions of this manufacturer.


Constructional Aspects


The enclosure is of 18mm high density chipboard and has no further bracing except for a horizontal webb across the top which supports the compression driver unit, thus relieving stress at the horn neck. Also, there's appreciably less internal absorption than with the Urei, with just a thin scrim of low density fibreglass quilt over part of the back and the four sides. Whereas the Urei has a single, short square reflex port, the JBL sports two smaller circular ports, each with a cardboard tube duct at least half the internal depth of the cabinet. So there is an immediate and obvious difference in the way the two enclosures are tuned.

The 2214 lo/mid driver and the horn flare are the front loaded and secured by machine screws engaging with tee nuts recessed into the chipboard.

The 2214 driver itself is visually identical to that fitted to the Urei 809, having the same chassis, the same cone, and a similar foam plastic front suspension. The magnet too is the same symmetrical field ceramic unit, including the hole through the pole piece for location of the co-axial horn unit in the case of the Urei, but in this instance, the screw thread to facilitate mounting the compression driver on the back of the magnet plate has not been cut. Also, whereas the Urei unit has the third spider suspension point at the base of the horn flare, the 2214 is a conventional single spider arrangement.

There does however seem to be a difference in suspension compliance, the 2214 being noticeably higher compliance than the unit fitted to the Urei, and would therefore be expected to exhibit a lower free air resonance. Such a difference would account for the different reflex tuning system employed.

The HF horn is of the now familiar JBL 'baby's bum' bi-radial, constant directivity design and is moulded from acoustically inert high impact structural foam. The 2416H compression drive unit is a recent development from JBL and is an attempt to provide good high frequency performance from a moderately priced unit with a standard european 1.375" x 27tpi screw thread coupling. It features JBL's latest titanium dome and diamond suspension technology and, unusually in a driver whose design parameters are governed by cost constraints, the diaphragm and phasing plug are in a compression chamber at the rear of the magnet assembly. That fitted to the 4425 is a bare bones version of the commercial product with no cosmetics, but does seem quite a nice unit. Exactly the same unit is fitted to the Urei 809.

The crossover appears to be a fairly complex affair and is mounted on a PCB attached to the back panel of the cabinet so that the screw terminals protrude through an appropriately placed cut-out. Apart from the user controls and a large laminated iron cored inductor (presumably the series inductor in the lo/mid leg of the network which is separately mounted to avoid undue strain on the board), all components are on the one circuit board and appeared to be of an adequate quality and rating, with those Mexican capacitors much in evidence.


Test Results


Figure 5 shows the impedance/frequency curve. It can be seen that the lowest value reached is 12Ω, compared with a value of 6Ω given in the maker's specification. I really can offer no justification for this anomaly, as the 4425 was measured immediately after the Urei 809, on the same equipment and the same set-up, and was checked for accuracy afterwards. But 12Ω was the figure produced each time. In other respects, the general characteristic is very similar to that recorded for the 809, including a similar system resonance at 60Hz, and apart from that, it's value is in close agreement with the curve given in the manufacturer's literature.


Click image for larger view
Figure 5. JBL 4425 impedance/frequency curve.


Again, two amplitude/frequency curves were taken at 1W at 1 m in order to avoid confusion in illustrating the effect of the mid and HF level controls. Figure 6a shows the mid-range variation available with the HF control at its maximum (flat) setting whilst Figure 6b shows the high frequency variation available with the mid-range control set at its flat position. According to the control panel calibration, the range of control provided should be between +2dB and -8dB in the case of the mid-range level control and between flat and -7dB in the case of the high frequency control, and it would seem as if this is in fact what is happening.



Figure 6a. JBL 4425 amplitude/fequency response showing mid-level control range at 1W.




Figure 6b. JBL4425 amplitude/frequency response showing HF level control range at 1W.


Using the upper curve of Figure 6b as the nominally flat response curve, the sensitivity works out at 91 dB, which is in exact agreement with the maker's specification, and the useful frequency response at 45Hz-17kHz, which again is close to the maker's figures.

Figure 7 shows the amplitude/frequency response at 6dB below rated power (in this case 50w RMS sine wave) and indentifies the second and third harmonic distortion components. It can be seen that there is a small flurry of activity below about 200Hz amounting to some 1.5%-2% in all, and then the usual rising distortion normally associated with compression-type drive units, rising to around 10% above 10kHz. Nothing untoward here.



Figure 7. JBL 4425 amplitude/frequency response showing 2nd and 3rd harmonic distortion at 6dB below rated power.


Figure 8 shows the horizontal polar response characteristics at 800Hz, 2kHz, 5kHz and 10kHz and it can be seen that the 4425 certainly lives up to its constant directivity design objective, with no more than a few dB deviation from the stated 100° Figure throughout the range. The asymmetry is due to the HF horn being offset to one side of the baffle panel. This really is quite an achievement in such a small loudspeaker system and demonstrates excellent control.



Figure 8. JBL4425 horizontal polar response.


Unlike the Urei co-axial design, where drive unit displacement has to be compensated for electronically, in the case of the 4425 the two drive units are physically aligned one above the other, thus resulting in a system which is naturally time-aligned and therefore does not require special correction. According to the maker's literature however, a 0.4mS time delay is introduced due to the phase response characteristic of the crossover network, but according to research carried out by Blauert and Laws, this is well below the level of perceptibility. In practice, the measured data at 1 metre was 3.4mS for the LF driver and 3.3mS for the HF driver, showing a time alignment error of 0.1 mS.

Tabulated Test Data

Nominal Impedance 8Ω.
Minimum Impedance 12Ω at 100/200Hz and 10kHz
Fundamental Resonance 60Hz
Sensitivity 91dB @ 1w @ 1m average 50Hz-16kHz
Useful Response 45Hz-16kHz
Distortion 2% maximum below 2kHz, rising to 10% at 10kHz at 6dB below rated power
Time Alignment 0.1 mS error
Horizontal Polar Resp 100° @ 800Hz
60° @ 2kHz included angle
100° @ 5kHz @ -6dB points
90° @ 10kHz


Auditioning


Standing alone, the 4425 is an impressive loudspeaker, with particularly clear, well dispersed highs and impressive low frequency performance, if a little on the woolly side by comparison with my regular home hi-fi loudspeakers. But without being able to identify the reasons why, it seemed to me unexciting for some reason.

The first thing to strike home is the laid back, smoother subjective response of the 4425 when compared to the strident aggression of the Urei. The high frequencies in particular are more open than with the Urei and the bass is more forward, but it somehow lacks the attack and that uncanny impression of presence and loudness which characterise the Urei sound. Also sadly missing is that imaging accuracy.

With the JBL, the strings sound sweeter, the bass more rounded and full, and it sounds just as good on a Shostakovich symphony as it does on Dire Straits, making it obviously a better all-round choice, but gone is that screaming Knopfler guitar break in the live recording of 'Sultans' or the raucus rasp of Mel Collins' sax in 'Two Young Lovers'. To me, after the Urei 809, it is rather tame by comparison, but to others, the sweeter sound of the JBL was the more acceptable of the two.

As far as a studio monitoring application is concerned, it does not seem to have that absolute accuracy and imaging quality of the Urei either. But we must put all this into perspective. Had I not been reviewing the Urei at the same time, I would have rated the 4425 very highly, and it's indeed an excellent loudspeaker in all respects. It's just that the Urei 809 has something extra that really brings rock and roll music to life and sends that little shivering sensation down the spine at times. (You know what I'm driving at.) But that's not all; it has this phenomenal accuracy and definition as well which must render it just about the best small studio control room or near field monitor going.


Conclusions


Because of its very smart presentation and because its performance characteristics do not seem to favour any particular type of programme material, it will have a wide variety of applications outside the studio control room and would be equally acceptable in the smartest of playback lounges, editing suites, presentation studios, offices or homes.

Like the Urei, it's audibly better when driven by a large power amplifier and for studio use, it will benefit from active room EQ in addition to its inbuilt response contour controls, excellent though these are for more general applications.

The maker's literature is first class and includes a far more detailed specification than we have published within this review, with virtually all electrical and acoustical data amplified by no less than 24 graphs! The performance characteristics are fully described and the technical foundation and limitations of the data given is stated. And, interestingly, apart from that impedance anomaly, the data given is extremely close to our own laboratory resultsand observed details.