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JBL 4349 Review (Studio Monitor Speaker)

changer

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I advise you to get yourself higher stands! Today I bought me some JBL JS360. But after they where delivered, I had to find out the stand is 5 cm shorter at only 35 cm high, not 40 cm as advertized. But then again, they only cost 18 Euros? I can live with that! :cool:

js330-new-cav_web_2.jpg


Well, you might notice, I had no time to loose and use the drill to screw them together, instead, I put the pieces on top of each other and began to listen to the speakers immediately, now imaging in the midst of the room, nicely elevated. The lower frequencies are not stuck in the floor no more. This is very, very pleasant now, whole different experience!
 
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dfuller

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Zvu

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Why would anyone listen 12"+wg loudspeakers nearfield ? That's probably the worst thing you could do to yourself.

Trying to eat a soup with a fork comes to mind.
 

Frgirard

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The audiophiles listen too far of their speakers.
The performance of a psi audio a25 or a kh420 are given at 2.3 m.
 

Zvu

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The audiophiles listen too far of their speakers...

This is one of those pure nonsense statements that you can come across coming here.

Instead of heavily generalizing and putting people into groups (audiophiles vs ... who ?) try to understand why is there specified listening distance with pro loudspeakers and why is it given often for pro and pa and not so often in speakers for home listening.
 
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changer

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changer, you need to work on limiting the ctc distance, something like this. but even that is on its limits for near field listening :)

Hi peanuts,
my previous provisional cabinet was oriented towards a close c-to-c distance with the same asymmetric waveguide. This approach is the legacy of a set of assumptions that the people who popularized the constant directivity horn speaker with DIY-ers put up as their approach, but they themselves were following some rule of thumb. This assumptions where 1) guided by the assumed relevance of asymmetric waveguides to control flour and ceiling bounce and 2) controlling the lobe tilt and the phase coherence of a passive speaker. The first design criteria is wrong, my use of an asymmetric waveguide nothing but a legacy of this false assumption. Not only is the tight driver spacing uneccessary, but also, the early loss of pattern control due to too small vertical dimensions of the waveguide lead to pattern flip below and above the crossover which show up in the early reflections as unwanted energy. It is much more important to control the vertical pattern to the same degree as the horizontal pattern, giving you real constant directivity. The second consideration is not of concern to me, as I use an active crossover with delay.

Further, the creator of the simulating software VituixCAD, Kimmo Saunisto, persuasively showed that a close c-to-c approach with two way speakers has other problems, when 1/4 wavelength cannot be achieved, and this is the case most times in a two way system: If both radiators are too close to each other in a two way system, due to the energy sum of both radiators on the vertical axis, the DI and sound power curves feature a stark and high Q curve, discontinuous and not desirable for an optimized in-room response. The current driver spacing of this speaker cabinet is optimized for an even DI throughout the crossover region, it is 1.2 lambda, which is ~ 33 cm at the 1250 Hz crossover frequency. In combination with a waveguide which is i. e. axisymmetric or rectangular, but with a vertical pattern the same as the horizontal, like a M2-style waveguide, sound power and DI will be optimal. As both radiators, woofer and the waveguide, feature a big surface area, the problem of driver spacing is further reduced.
 
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tom1040

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This came from another reviewers on the 4349:

  • JBL comments: Notice that the design actually intentionally includes the slight dip in the sound power near crossover, as it helps accentuate and make the high frequencies sound more detailed without actually raising their level (as in our older studio monitors).
    I concur with the design choice and think that the effect is exactly what is needed.

Any thoughts on this?
 

Tom C

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This came from another reviewers on the 4349:

  • JBL comments: Notice that the design actually intentionally includes the slight dip in the sound power near crossover, as it helps accentuate and make the high frequencies sound more detailed without actually raising their level (as in our older studio monitors).
    I concur with the design choice and think that the effect is exactly what is needed.

Any thoughts on this?
I’m no expert, but that sounds like a load of ———to me. The dip is way too narrow to have that effect.
 

Chromatischism

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I’m no expert, but that sounds like a load of ———to me. The dip is way too narrow to have that effect.
Not only that, most speakers have that and it serves to reduce harshness from the change in directivity. Reviewers need to be careful when assuming a crossover dip is inherently bad, and they especially should not assume it would be better if boosted with EQ. Some EQ systems, like Audyssey, avoid doing so for that reason.
 
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changer

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Not only that, most speakers have that and it serves to reduce harshness from the change in directivity (you would otherwise see the reflections increasing in strength there).
As you pointed out, this is a solution for direct radiator speakers without the use of waveguides. The 4349 stems from constant directivity concepts, a design who's basic principles was already laid out by Keele in the 1980s: https://www.aes.org/e-lib/browse.cfm?elib=4573
Here, the off-axis energy resembles the direct sound and therefore no dip in on-axis is needed to deal with unwanted energy that would be represented in sound power curve, and hence would be perceptible in-room listening (Projected In-room Response = 12% listening window, 44% early reflections/sound power each) . As this is precisely what JBL championed with this concept over decades, it is highly unlikeable that the statement tom1040 found in a review (which?) is correct. A look at the sound power curve of 4349 reveals this: it tracks the direct sound. The dip is not helping with anything here.
 
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Chromatischism

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As you pointed out, this is a solution for direct radiator speakers without the use of waveguides. The 4349 stems from constant directivity concepts, a design who's basic principles was already laid out by Keele in the 1980s: https://www.aes.org/e-lib/browse.cfm?elib=4573
Here, the off-axis energy resembles the direct sound and therefore no dip in on-axis is needed to deal with unwanted energy that would be represented in sound power curve, and hence would be perceptible in-room listening (Projected In-room Response = 12% listening window, 44% early reflections/sound power each) . As this is precisely what JBL championed with this concept over decades, it is highly unlikeable that the statement tom1040 found in a review (which?) is correct. A look at the sound power curve of 4349 reveals this: it tracks the direct sound. The dip is not helping with anything here.
But there is directivity change there where the dip is:

index.php


I have noticed that normally the dip matches a widening (look at the ELAC DBR), but here there is a narrowing. Therefore maybe a dip is not good here.
 

changer

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Yes, this is precisely what I said: because this speaker features a constant directivity waveguide that is matched to the directivity of the woofer, the concept Keele laid out in the 1983 paper, there should not be a need for a dip. Why do speakers have intentional dips in the frequency response? Engineers use it when tweeter directivity is lower/wider than woofer directivity in the crossover region and a directivity error results: too much off-axis energy of the tweeter, that is radiating wide, to little of the woofer, which is already beaming. The dip in direct sound frequency response then counters the indirect sound power surplus. In these cases, the dip is only seen in direct sound, but it mitigates a peak in indirect response to reach a flat(ter) sound power curve. This helps for a better overall in-room response.

Which is unnessesary with a constant directivity speaker. A constant directivity speaker avoids directivity errors from the start. That is also why the dip in 4349 was measured both in listening window/direct sound AND in sound power. Here, it serves no purpose. It is not a feature, it's a bug.
 

changer

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Without criteria, I cannot follow your objection, what's your point specificially? For the concern raised, dips in on-axis as a mitigation for wide directivity tweeter radiation off-axis, the 4349's FR is essentially that of a constant directivity speaker. The dip is within the range of 500 Hz to 10000 Hz, where radiation pattern is almost uniform and the dip itself is both in direct and sound power.
 

Chromatischism

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What does constant directivity mean to you? To me it means the directivity index sees no change through the frequency range. This speaker sees a narrowing as frequency increases, like most speakers do.
 

Prolix

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Not only that, most speakers have that and it serves to reduce harshness from the change in directivity (you would otherwise see the reflections increasing in strength there). Reviewers need to be careful when assuming a crossover dip is inherently bad, and they especially should not assume it would be better if boosted with EQ. Some EQ systems, like Audyssey, avoid doing so for that reason.
Are you referring to Audyssey's default midrange dip? I have no idea what Audyssey does and doesn't actually do, but I know from using the editor app that the "after" curve shows that every dip is boosted. Feel like I'm missing something here.
 

Chromatischism

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Are you referring to Audyssey's default midrange dip? I have no idea what Audyssey does and doesn't actually do, but I know from using the editor app that the "after" curve shows that every dip is boosted. Feel like I'm missing something here.
You are probably in the habit of turning off MRC. That's fine if you craft your own to follow the speaker's response. The problem is Audyssey doesn't show us the measured response on the editor screen so we can't trace it. Such an obvious feature. Tracing the measured response would allow us to smooth out the irregularities while avoiding the broad level changes due to adherence to a target curve that may not be the best. But that's for another thread.
 
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