JBL 4349 Review (Studio Monitor Speaker)

[Duke]

For intermediate listening distances (2 meters plus) I like Controlled Dispersion angles in the range of 100 to 120 degrees. I toe in the speakers to cross the axis of speakers in front of the listening position. If I move left I am more off axis of the left speaker and the direct SPL of the left speaker is reduced. Also as a result of moving left I am farther from the right speaker but closer to the right speaker axis, the right speaker SPL increases. Moving to the right all the opposite things happen.

With 110 to 120 +-6dB degree coverage you can get up and move around, the illusion of being there seems to be real.

I have done this with 60 degree, 80 degree, 90 degree and other Controlled Dispersion Waveguides.

I can tell you that controlled dispersion is important to the illusion of being there.

I agree with everything you say here, though I haven't tried using speakers which have controlled dispersion out beyond 100 degrees (-6 dB @ 50 degrees off-axis). I've been designing speakers for time/intensity trading for many years.

You mention "the illusion of being there" and ime that is a challenge, at least for two-channel. The in-room reflection path lengths cannot possibly be long enough to mimic the venue cues, BUT the venue cues ARE on the recording. So imo the challenge is to effectively present the venue cues which are on the recording while minimizing and/or disrupting the "small room signature" cues of the playback room. To put it briefly, I agree with you that controlled dispersion is a key to accomplishing this.

 

[LTig]

[..]
Dynamic contrast does not show up in any of the spin data and is at best only indirectly suggested by the distortion data. I had an interesting (and all-too-brief) conversation with Floyd Toole on another forum which included the subject of rapid-onset power compression due to voice coil heating , and he had this to say:

"The audibility of power compression in its many variations probably could use some more research to define what is audible and what is tolerable. The magnet heating that you describe is important in pro audio sound reinforcement systems where the loudspeakers are required to work at or close to their design limits for long periods. Such heating and cooling has a very long time constant. This is not the case in most home systems. Although the modification of motor strength through magnet heating is a factor, most of the audible effects are from voice coil heating, which has a much shorter time constant. I just saw a test of a high-end audiophile speaker that in going from an average level of 70 dB (loud conversation, background music) to 90 dB (a moderate crescendo, or foreground rock listening) lost about 4 dB in output over about 3 octaves in the mid-high-frequency range. It became a different loudspeaker at different listening levels." [emphasis Duke's]
[..]

The effect of voice coil heating on SPL is the rise of the resistance which leads to proportional less current and hence to less excursion. I think that it should not be too difficult to dynamically measure the resistance of the voice coil.

The idea which popped up is to measure voltage and current at the same time with a DSO and use the DSO's math capabilities to display voltage divided by current. In theory one could feed the voice coil a time limited sinus signal with high power and watch the resistance shown on the scope (in practice the phase angle between voltage and current may make this impossible, have to think about this). Has something like this been done before?

 

[Robh3606]

The effect of voice coil heating on SPL is the rise of the resistance which leads to proportional less current and hence to less excursion. I think that it should not be too difficult to dynamically measure the resistance of the voice coil.

Here is an attempt at measuring VC temperature

https://www.stereophile.com/reference/1106hot/index.html

JBL addresses this in the 2216nd woofers. They use negative TCR wire in the VC. Have a patent for it.

Rob

 

[thewas]

Here is an attempt at measuring VC temperature

https://www.stereophile.com/reference/1106hot/index.html

JBL addresses this in the 2216nd woofers. They use negative TCR wire in the VC. Have a patent for it.

Some B&O loudspeakers have a model which estimates VC temperature and compensate the FR changes by DSP:
https://www.tonmeister.ca/wordpress/2014/01/16/bo-tech-thermal-compression-compensation/

 

[LTig]

Since it has not been mentioned yet as far as I had followed this thread: Comparisons of the 4349 with near field studio monitors do not make much sense, the typical usage scenarios are too different. Worthy alternatives to the 4349 are IMHO mid/far field studio monitors with higher SPL and narrower sound field:

• Genelec S360 (10"/1.7" 2-way with 350W total amplification)
• Neumann KH420 (10"/3"/1" 3-way with ~800W total amplification)

Prices of both are similar and somewhat higher than the 4349 but you spare the power amp.

 

[ShawnL]

What on earth is the point of having such a massive waveguide and compression driver when you are crossing it this high? These should be going down to 900hz at least. What a laugh.

 

[Robh3606]

Some B&O loudspeakers have a model which estimates VC temperature and compensate the FR changes by DSP:
https://www.tonmeister.ca/wordpress/2014/01/16/bo-tech-thermal-compression-compensation/

Quote from the presentation:

"In essence all we need to do is to take Figure 4, flip it upside down and make a filter that “undoes” the effect of temperature on the loudspeaker’s response. In other words, if (because the woofer gets 160°C above “normal”) it drops 3 dB at 20 Hz, the BeoLab 5 knows this and adds 3 dB at 20 Hz. So, built into the BeoLab 5 is a set of filters that are used, depending on the temperature of the woofer’s voice coil. These filters are shown in Figure 5."

OK am I missing something?? Won't adding 3db more power just make matters worse? Now we have twice the power as before?? So more power hotter wire! Looks like a viscous cycle to me.

Rob

 

[DualTriode]

"the illusion of being there" is very much related to "the willing suspension of disbelief".

The balance of direct sound and reflection is just enough reflection to provide some sense of space. It is like salt in your soup, a little bit helps.

We listen in such small spaces in our homes, I would not look for listening room reflections to provide evidence of an additional or 2nd venue. As you say clues to venue should be in the recording.

Thanks DT

Oops I neglected one thing.

The M2 waveguide is 120 degrees H and 100 degrees V.

 

[richard12511]

they didn't 'sound' loud at all until I tried to talk to a colleague and had to all but shout. Now, is this the promoted clean natural sound of the speakers used, or are they compressing the dynamics slightly into a pleasant 'wall' of sound?

This has been my experience as well with truly dynamic speakers. They don't sound nearly as loud as they actually are. I live alone, so my test is usually to sing along. If I can comfortably listen at levels with which I can sing along as loud as I want and not mess up the song, then the speakers are pretty capable .

 

[jhaider]

Since it has not been mentioned yet as far as I had followed this thread: Comparisons of the 4349 with near field studio monitors do not make much sense, the typical usage scenarios are too different. Worthy alternatives to the 4349 are IMHO mid/far field studio monitors with higher SPL and narrower sound field:

• Genelec S360 (10"/1.7" 2-way with 350W total amplification)
• Neumann KH420 (10"/3"/1" 3-way with ~800W total amplification)

Prices of both are similar and somewhat higher than the 4349 but you spare the power amp.

It's also too bad Amir didn't have a JBL 708 on hand to compare. Smaller all around, less sensitive and certainly uglier, but with constant dispersion an octave higher (horn exit on 7-series is only 0.5") and a more sophisticated woofer design (neo "Differential Drive" motor rather than a refinement of the ceramic magnet overhung design JBL's been doing since the AlNiCo crunch.)

Interestingly despite the smaller horn and less capable tweeter on 708, crossover frequency seems similar. JBL Synthesis actually claims to take the tiny single-diaphragm 0.5" exit 2409 compression driver down to 1.3kHz in their in-walls. I should stick a mic at the plane of the mouth of my SCL-3 to see if that's actually the case.

 

[Duke]

Here is an attempt at measuring VC temperature

https://www.stereophile.com/reference/1106hot/index.html

The problem with the measurement technique is revealed in the section entitled "making the measurements":

"For the measurements, the DC voltage across the voice-coil was recorded at intervals of 10 milliseconds... The data were then smoothed using a five-second moving average calculation..."

In other words, they sampled the voltage across the voice coil at regular intervals and then smoothed the results. This UTTERLY FAILED to capture the instantaneous effect of the voice coil heating which occurs at the moment of a peak.

This is NOT my area of expertise and I do not know how to design a test which would reveal thermal modulation due to instantaneous voice coil heating on the peaks, but I'm pretty sure that taking measurements at regular intervals (instead of at the peaks) and then smoothing(!) the data is not it.

Unfortunately the finding of that article (that thermal effects are of negligible real-world significance in home audio) has been accepted as "the science" on the subject. Occasionally someone's ears tell them otherwise, @amirm's for example.

 

[hardisj]

Klippel has all sorts of modules that keep track of voice coil temperature. Their LSI module (most famous for determining linear Xmax) will track VC temp for as long as you tell it to.

http://www.klippel.de/products/rd-system/modules/lsi3-large-signal-identification.html

 

[Frank Dernie]

You mention "the illusion of being there" and ime that is a challenge, at least for two-channel. The in-room reflection path lengths cannot possibly be long enough to mimic the venue cues, BUT the venue cues ARE on the recording.

IME this is mainly a recording related phenomenon.
On some recordings there is a lot of "venue sound" in the recording, this is particularly true of live recordings with a limited number of microphones. IME these sound the most realistic and best with narrow directivity speakers.
On most, particularly any since multi track recorders, studio recordings have no actual venue acoustic in the recording at all so, inevitably, at the mixing stage there may be a bit of artificial ambience added but basically there is nothing real there, then the listening room acoustic is probably pretty important in the creation of a space illusion. These sort of recordings will probably, therefore, sound more spacious using wider directivity speakers.

The way I see it, one is trying to reproduce the venue acoustics and the other trying to create the impression of one.

As ever the SQ of the recording is much more varied than the SQ of our equipment and what sounds most accurate to me for the old and live recordings I own, including my own, has been narrower directivity speakers, and since these are frequently my favourite recordings I use wider directivity speakers more rarely and put up with the loss of faux spaciousness.

 

[Andysu]

This is a review and detailed measurements of the JBL 4349 2-way Studio Monitor (passive). All of you were too cheap to buy one so I had to do it myself. Out of my own money no less! Luckily I got a discount from the retail cost of US $7,500 for a pair.

Note: our company, Madrona Digital, is a dealer for Haman, parent company of JBL. So feel free to read as much bias as you like into the following review.

The 4349 has the familiar look of "giant studio bookshelf" of the past:

View attachment 125315

The walnut finish though makes it more suitable for domestic use especially if you leave the woofer grill on (I took mine off for all of my testing as you see above). Typical of many Pro products there are a couple of trim controls but they only act on the tweeter. Response will be shown in the measurement section. The main measurements are with the dip switches at 0 dB setting.

As you can see above, this thing is not small. It is also not light. It took us to lug it around and with just the ports as handles, it was not easy!

Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.

I performed over 1400 measurement which resulted in error rate of less than 1% until 10 kHz where the error started to linearly climb. So don't go by micro detail of the response in that region.

Testing temperature was around 69 degrees F.

Reference axis for measurements was the center of the tweeter (by eye). Grill was not used in either measurements or listening tests.

Measurements are compliant with latest speaker research into what can predict the speaker preference and is standardized in CEA/CTA-2034 ANSI specifications. Likewise listening tests are performed per research that shows mono listening is much more revealing of differences between speakers than stereo or multichannel.

JBL 4349 Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker is and how it can be used in a room. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:

View attachment 125316

I must say, I did not at all expect this kind of response from any product coming out of Harman. The dip at the crossover? I finished the measurements late at night and was miserable till I listened to the speaker today. Clearly a shelving boost is implemented for the tweeter. Fortunately if you turn the dip switches to -1, you should be able to knock that down:

View attachment 125317

The big trough occurs in my measurement "lab" when the mic is aligned with tweeter axis. I moved the mic down to the logo between the tweeter and woofer and the dip shrank to what you see in the spin data. So ignore that.

Back to crossover issue, here is our near-field measurement:

View attachment 125318

Looks to me like the woofer response is drooping too much before the tweeter gives it a hand and hence the dip there. Not sure if the tweeter could handle the load there. There are also a couple of port resonances that interfere with the response.

Our early window response is similar to on-axis which bodes well for ability to EQ:

View attachment 125319

The dip gets worse with floor and ceiling reflections. I am lucky in having a super thick carpet (4 inches or so) and tall ceilings.

Edit: forgot the PIR graph:

View attachment 125346

The star of the show is the tweeter and its directivity:

View attachment 125320


View attachment 125321

Have we seen anything this pretty? It looks textbook correct. Shame about the crossover dip before it.

Vertically, you are better off being at or below tweeter axis. I sat below it for listening tests:

View attachment 125322

An excellent supporting cast is the ultra low distortion in bass:

View attachment 125323

This thing is as good as many excellent headphones at 86 dBSPL as far as distortion!

View attachment 125324

Strange though to see the tweeter complain at higher amplitudes.

Waterfall shows some resonances due to the port:

View attachment 125325

I felt the cabinet during music and it was solid as a rock so these are acoustic ones.

Finally, impedance is substantially higher than typical 2-way speaker at 8+ ohm:

View attachment 125326

JBL 4349 Listening Tests
I must say I was in bad, bad mood before listening tests started. Had the bad measurements on top of killing myself dragging this speaker up to second floor where my listening test is. Turned on the music and wow, there was hardly much to complain about! Speaker was highly efficient and was able to pump out dynamics that were startling at times. There was a bit of brightness despite me sitting lower than the treble so I dialed in the dip switches to -1 and -1. Standing up I could hear more highs but it would be tricky to balance the clarity I was hearing versus increase high frequency energy.

I wanted to see the effect of that crossover dip so dialed in an EQ for it:

View attachment 125327

As with headphones, I could here a slight opening up of the sound and more forward/pleasant representation of female vocals I was listening to. Overall effect though was small due to the bandwidth being low (1 kHz or so). The eye was bleeding due to the graphs far more than the ear seemed to care!

I had to put in the dip at my usual 105 Hz to tame a room mode. It was not necessary for the JBL 4349 but was in what to come: comparison to my Revel Salon 2 next to it. Figured one of you rascals would ask me about it so I figured I do the work now! Immediate reaction was wow, the Salon 2s have far deeper bass. Visual impression of 4349's massive woofer (compared to Revel's) makes one think there is a ton of deep bass but there is not. To match the Salon 2 would you need a sub. That on the other hand meant that the 4349 didn't activate the room modes much so had a light, tight and dynamic bass.

Beyond the bass the impression of the two speakers was so different. The salon 2 was producing a smooth, highly integrated sound column. The 4349 seemed to have a dual character where it would be come extremely lively with high frequency dynamics. This was super pleasurable but less refined than Salon 2's reserved but excellent reproduction. My thought during the whole affair was that you really wanted both of these speakers and use them based on mood and music.

This is one of few good sounding speakers that don't have the "Revel sound" to me. It is a different way of solving the same problem.

Conclusions
As indicated above, objective test results left a sour taste in my mouth post measurements. It was not until I listened to the speakers that I got what this speaker is all about:

1. Marketing says you have to have a huge woofer and tweeter. Don't care what else you do but it has too have this retro look.

2. Engineering says so they want to compete with a party speaker. Let's build the least broken, best version we can.

So no, the 4349 is not objectively perfect. That crossover dip pushes it out of the running compared to any modern studio monitor. What it is, is re-implementing an old speaker configuration with the best know-how they could put in there. An active version would have dealt with the deficiency there but the formula did not allow it. Fortunately we can put EQ in front of the speaker and remedy that.

A side note. I hardly ever come home from a show thinking of replacing my speakers with anything I see there. The only exception was a set of large horn speakers that had dynamics that I could not replicate with my Salon 2s. The 4349 allowed me to get there and so points to high efficiency mattering. People routinely underestimate how much power it takes to reproduce dynamics well. Even my high power amplifier struggles to push the Salon 2 there. But with 4349, that struggle disappeared with a bunch of headroom left.

I am going to put the JBL 4349 on my recommended list. Go ahead and hate on me due to objective measurements above. I am ready to take it!

------------
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150

amirm, Blimey, wow review (I like JBL speakers) that is a lot to read. It's more than you write up for these avr/avp and this is just a JBL speaker with passive 2-way crossover network.
Have you ever considered to look at it and improve it with a DSP crossover connected to LF and HF? And do the test again.

 

[thewas]

OK am I missing something?? Won't adding 3db more power just make matters worse? Now we have twice the power as before?? So more power hotter wire! Looks like a viscous cycle to me.

You have of course a good point there, on the other side music usually is not static and such high tech DSP loudspeaker usually have also driver protection which can reduce the current when the modeled voice coil temperature exceeds a predefined limit.

 

[okok]

that's lots of time to measure these

 

[Valentin R]

Quick note on changing the reference axis. I can't tilt the angle like you all can visually by using the spin data. I only have controls in Z which I can lower to be something else. In other words, the on-axis is at 90 degrees to the speaker and I can only move it up and down. Is this what you all want? If so, where should that point be?

 

[Robh3606]

The problem with the measurement technique is revealed in the section entitled "making the measurements":

"For the measurements, the DC voltage across the voice-coil was recorded at intervals of 10 milliseconds... The data were then smoothed using a five-second moving average calculation..."

In other words, they sampled the voltage across the voice coil at regular intervals and then smoothed the results. This UTTERLY FAILED to capture the instantaneous effect of the voice coil heating which occurs at the moment of a peak.

This is NOT my area of expertise and I do not know how to design a test which would reveal thermal modulation due to instantaneous voice coil heating on the peaks, but I'm pretty sure that taking measurements at regular intervals (instead of at the peaks) and then smoothing(!) the data is not it.

Unfortunately the finding of that article (that thermal effects are of negligible real-world significance in home audio) has been accepted as "the science" on the subject. Occasionally someone's ears tell them otherwise, @amirm's for example.

Hello Duke

I agree with you. Unfortunately aside from long term effects of power compression being well documented that is the only short term "attempt" to measure I have seen. If I remember right Earl and Greg Timbers feel this is an issue that is audible and should be addressed as well in the speaker design.

I look at the limiter " bulbs" that are used in some systems to protect the tweeters/compression drivers. When there is too much power they heat up and limit the current to the driver. You can hear that compression. I don't see why you would not have the same effect short term. It's the exact same mechanism.

I put a high priority on the dynamics and typically the pro drivers loafing at a couple of watts take the prize. I realize this is just subjective opinion.

Just drop on Dire Straits Telegraph Road.

Rob

 

[Robh3606]

You have of course a good point there, on the other side music usually is not static and such high tech DSP loudspeaker usually have also driver protection which can reduce the current when the modeled voice coil temperature exceeds a predefined limit.

Yes but if you limit power it has the same effect of reduced output on peaks. So I question if these fixes are actually fixes. Sounds more like marketing to me.


Rob

 

[thewas]

Yes but if you limit power it has the same effect of reduced output on peaks. So I question if these fixes are actually fixes. Sounds more like marketing to me.

The difference is that you can have for a longer listening period a linear FR and only when you exaggerate too much the limiter comes into action.