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JBL 4309 Review (Speaker)

amirm

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This is a review and detailed measurements of the JBL 4309 2-way speaker. It was kindly purchased new by a member and drop shipped to me. The 4309 costs US $2,000 for a pair.

NOTE: our company Madrona Digital is a dealer for Harman products including the JBL Line. While the measurements are performed just like any other speaker and hence can't be "gamed," you are welcome to read any kind of bias you like in my subjective assessment.

The 4309 is a shrunk version of its larger brothers and somehow manages to look very cute!

JBL 4309 Review 2-way horn speaker Synthesis.jpg


It is like a half-scale version of a super car! Back panel nods to audiophile market with bi-wire binding posts:

JBL 4309 Review back panel 2-way horn speaker Synthesis.jpg


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. Using computational acoustics, far-field response is computed and that is what I present. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber.

I performed over 1000 measurement which resulted in error rate of about 1%.

Reference axis is approximately the center of the tweeter. Grill was not used.

JBL 4309 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:

JBL 4309 Measurements frequency response 2-way horn speaker Synthesis.png


The eye immediately goes to that bunched up response around 700 to 1000 Hz. What is the cause? We can see it in near-field measurement of each driver:

JBL 4309 Measurements driver frequency response 2-way horn speaker Synthesis.png

We have a boost in that region from the woofer which I suspect is due to baffle step. If so, interesting that they chose to not compensate for it. We also have a port/cabinet resonance there so the combination becomes erratic.

Near-field response looks cluttered in that same region:

JBL 4309 Measurements early window frequency response 2-way horn speaker Synthesis.png

Fortunately it looks like floor reflection makes that bump worse so by using a thick carpet, its effect can be reduced.

Putting the two together, the predicted in-room response really shows this one bump and a smaller dip after it:

JBL 4309 Measurements Predicted in-room frequency response 2-way horn speaker Synthesis.png


Big or small problem? Visually it looks kind of big, no?

Forgot to note the slight bass boost around 120 Hz. From previous testing of other speakers with that there, I think that tends to be a positive, not a negative.

Get ready for a big smile when we look at horizontal beam width:

JBL 4309 Measurements horizontal beam width  2-way horn speaker Synthesis.png


Could they get this more perfect? I don't think so. It is almost a flat line. Not only that, the drop off is just as organized as you see in pink and green lines. I don't think we have seen studio monitors this good.

Same is reflected in our contoured plot:

JBL 4309 Measurements Horizontal directivity  2-way horn speaker Synthesis.png


Vertically naturally is not as perfect but still a lot better than many 2-way non-coaxial speakers:

JBL 4309 Measurements Vertical directivity  2-way horn speaker Synthesis.png


Zooming into three frequencies, we see very good behavior as far as 3-D dispersion:

JBL 4309 Measurements horizontal 3-D directivity  2-way horn speaker Synthesis.png


Crossover frequency is 1.6 kHz by the way.

When it comes to distortion, at 86 dB the 4309 is just cruising:

JBL 4309 Measurements Distortion THD 2-way horn speaker Synthesis.png


JBL 4309 Measurements Distortion 2-way horn speaker Synthesis.png


Even at 96 dBSPL, it keeps bass distortion from going through the roof.

Impedance is typical in the way it drops to 4 ohm:

JBL 4309 Measurements Phase and Impedance 2-way horn speaker Synthesis.png


JBL 4309 Listening Tests and Equalization
I listened to the 4309 without looking at the measurements first. I thought the overall sound was just fine. I then computed the response and was surprised at the bump around 1 kHz. Couldn't figure out why it was not bothering me. So I developed an EQ for it and the dip after it:

JBL 4309 Equalization Parametric EQ 2-way horn speaker Synthesis.png


The effect was so subtle that I had to resort to blind testing of the EQ to be sure it was making a positive difference. And it was but very subtle in the way it improved clarity. And perhaps reduced a touch of sharpness. But really, you could listen either way and still very much enjoy the sound of this speaker.

Where the 4309 really excelled was power handling. I pumped a ton of power into it and it kept getting louder and louder with no hint of distortion. I could not believe it. There is some magic tuning going on here in the way this speaker can produce nice tactile bass yet not fall apart when you asking to produce more and more until you give up before it does! I don't think there is a bookshelf speaker that can compete with it in this regard. You should have heard it thundering away despite me just playing a single speaker!

Back to the sound, half way through my listening tests, I started to enjoy the sound so much that I forgot I was reviewing them! I was just enjoying track after track and settling into the music. Audiophile life as it should be!

Conclusions
I like to think we know a lot about evaluating the sound of a speaker objectively and then comes a speaker like this were we can clearly identify flaws but somehow other nice characteristics of the speaker dominate so much that the issue becomes lost in a sea of goodness. Here, the perfect directivity and power handling plus what seems to be nice tonality carry the day. If I had just seen the measurements, I would have given this speaker lower score. But once I listened and judged the impact of the response error using EQ, it pushed me to give it very high regards. My definition of technology at its best is that it doesn't make you work around its limitations and such is the story of the 4309.

It is my pleasure to give high recommendation to JBL 4309.

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

Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

Attachments

  • JBL 4309 Frequency Response.zip
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richard12511

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Interesting review. Spinorama looks not so good(especially for $2,000), but directivity is great, and subjectively it does well, even without EQ. Wouldn't have expected a 5/5 tbh(especially without EQ), but it seems JBL has found a way to make the most of things here.
 

napilopez

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Ah, always fun to see an NFS of one of the speakers I've tested!

For what it's worth, my impressions are nearly identical to @amirm , including being a little baffled (heh) at why the messiness from 700 Hz to 2 khz didn't bother me. Just goes to show, some stuff is more offensive to the eye than ear indeed. In general, I find that a peak with a dip right next to it seems to be less offensive than if the full region peaks or dips. In general.

In reality it's not that big of a deal and the rest of the response is quite smooth, especially in the spatial attributes region from 2-10khz. A little narrower directivity than I like, but that's always the case with these big waveguide speakers.

I'm not at my PC for a direct comparison, but here was my spin. Looks very similar (note different scaling).

4309-Spin.png


I also recall the overall contour is very similar to the HDI-1600. Ironically, that speaker is a little cleaner, but I preferred this one.

I actually think I read somewhere that the dip at 1.8khz is on purpose? Something about it making the highs sound clearer without actually making it bright? Who knows =]
 

Madjalapeno

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Does it look better with the grill on?
 

ROOSKIE

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Amazing review. These look perfect for me and I like loud. So glad these were worth the time you spent. Deeply appreciate your effort greatly!!
 

richard12511

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I think this points to the importance of directivity and room interactions.

Agreed.

Also the ability to play full range and loud. That seems to be just as (if not more) important as a great spinorama, and these speakers ace that part of the test, though the $25,000 amps may exaggerate this compared to what most ends users will actually get.
 

ROOSKIE

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Does it look better with the grill on?
Ha
I think these look wicked cool.
Beauty is in the eye of the beholder of course.
Just excited as one can be on my end about these.
 

hardisj

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Also the ability to play full range and loud.

Well, the spinorama captures all these things except for the "loud" part. It captures directivity/room interaction and bandwidth.

And, to be clear, with a medium sensitivity and a rolloff starting around 100Hz, I wouldn't consider this speaker full range. Not anymore full range than other bookshelf sized speakers with a single woofer. (look at the distortion take off <100Hz as you increase volume above 86dB) Though, they did try to push it lower by extending the port tuning ... looks like they tried using a Chebyshev alignment. *shrug*
 
Last edited:

Maiky76

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This is a review and detailed measurements of the JBL 4309 2-way speaker. It was kindly purchased new by a member and drop shipped to me. The 4309 costs US $2,000 for a pair.

NOTE: our company Madrona Digital is a dealer for Harman products including the JBL Line. While the measurements are performed just like any other speaker and hence can't be "gamed," you are welcome to read any kind of bias you like in my subjective assessment.

The 4309 is a shrunk version of its larger brothers and somehow manages to look very cute!

View attachment 158483

It is like a half-scale version of a super car! Back panel nods to audiophile market with bi-wire binding posts:

View attachment 158484

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. Using computational acoustics, far-field response is computed and that is what I present. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber.

I performed over 1000 measurement which resulted in error rate of about 1%.

Reference axis is approximately the center of the tweeter. Grill was not used.

JBL 4309 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 158485

The eye immediately goes to that bunched up response around 700 to 1000 Hz. What is the cause? We can see it in near-field measurement of each driver:

View attachment 158486
We have a boost in that region from the woofer which I suspect is due to baffle step. If so, interesting that they chose to not compensate for it. We also have a port/cabinet resonance there so the combination becomes erratic.

Near-field response looks cluttered in that same region:

View attachment 158487
Fortunately it looks like floor reflection makes that bump worse so by using a thick carpet, its effect can be reduced.

Putting the two together, the predicted in-room response really shows this one bump and a smaller dip after it:

View attachment 158488

Big or small problem? Visually it looks kind of big, no?

Forgot to note the slight bass boost around 120 Hz. From previous testing of other speakers with that there, I think that tends to be a positive, not a negative.

Get ready for a big smile when we look at horizontal beam width:

View attachment 158489

Could they get this more perfect? I don't think so. It is almost a flat line. Not only that, the drop off is just as organized as you see in pink and green lines. I don't think we have seen studio monitors this good.

Same is reflected in our contoured plot:

View attachment 158490

Vertically naturally is not as perfect but still a lot better than many 2-way non-coaxial speakers:

View attachment 158491

Zooming into three frequencies, we see very good behavior as far as 3-D dispersion:

View attachment 158492

Crossover frequency is 1.6 kHz by the way.

When it comes to distortion, at 86 dB the 4309 is just cruising:

View attachment 158493

View attachment 158494

Even at 96 dBSPL, it keeps bass distortion from going through the roof.

Impedance is typical in the way it drops to 4 ohm:

View attachment 158495

JBL 4309 Listening Tests and Equalization
I listened to the 4309 without looking at the measurements first. I thought the overall sound was just fine. I then computed the response and was surprised at the bump around 1 kHz. Couldn't figure out why it was not bothering me. So I developed an EQ for it and the dip after it:

View attachment 158496

The effect was so subtle that I had to resort to blind testing of the EQ to be sure it was making a positive difference. And it was but very subtle in the way it improved clarity. And perhaps reduced a touch of sharpness. But really, you could listen either way and still very much enjoy the sound of this speaker.

Where the 4309 really excelled was power handling. I pumped a ton of power into it and it kept getting louder and louder with no hint of distortion. I could not believe it. There is some magic tuning going on here in the way this speaker can produce nice tactile bass yet not fall apart when you asking to produce more and more until you give up before it does! I don't think there is a bookshelf speaker that can compete with it in this regard. You should have heard it thundering away despite me just playing a single speaker!

Back to the sound, half way through my listening tests, I started to enjoy the sound so much that I forgot I was reviewing them! I was just enjoying track after track and settling into the music. Audiophile life as it should be!

Conclusions
I like to think we know a lot about evaluating the sound of a speaker objectively and then comes a speaker like this were we can clearly identify flaws but somehow other nice characteristics of the speaker dominate so much that the issue becomes lost in a sea of goodness. Here, the perfect directivity and power handling plus what seems to be nice tonality carry the day. If I had just seen the measurements, I would have given this speaker lower score. But once I listened and judged the impact of the response error using EQ, it pushed me to give it very high regards. My definition of technology at its best is that it doesn't make you work around its limitations and such is the story of the 4309.

It is my pleasure to give high recommendation to JBL 4309.

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

Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

Hi,

Here is my take on the EQ.

These EQ are anechoic EQ to get the speaker right before room integration. If you able to implement these EQs you must add EQ at LF for room integration, that usually not optional… see hints there: https://www.audiosciencereview.com/...helf-speaker-review.11144/page-26#post-800725

The raw data with corrected ER and PIR:

Score no EQ: 3.6
With Sub: 5.6

Spinorama with no EQ:
  • Not Smooth
  • Some resonances
  • Great directivity except around 1kHz
JBL 4309 No EQ Spinorama.png

Directivity:
Better stay at tweeter height
Horizontally, anything up to 20deg.
JBL 4309 LW Better data.png

JBL 4309 2D surface Directivity Contour Only Data.png

EQ design:
I have generated one EQ. The APO config file is attached.
  • The EQs are designed in the context of regular stereo use i.e. domestic environment, no warranty is provided for a near field use in a studio environment although the LW might be better suited for this purpose.
  • LW EQ is very close to Score EQ so only the score EQ is shown

Score EQ Score: 5.5
with sub: 7.3

Code:
JBL 4309 APO EQ Score 96000Hz
October122021-102859

Preamp: -2.9 dB

Filter 1: ON HPQ Fc 36.02,    0.00,    1.30
Filter 2: ON PK Fc 117.57,    -2.90,    1.54
Filter 3: ON PK Fc 289.13,    1.61,    1.75
Filter 4: ON PK Fc 981.38,    -2.90,    3.98
Filter 5: ON PK Fc 1270.08,    -2.31,    3.99
Filter 6: ON PK Fc 1719.16,    2.97,    3.03
Filter 7: ON PK Fc 4297.87,    -1.60,    1.36
Filter 8: ON PK Fc 11808.64,    3.00,    3.99
JBL 4309 EQ Design.png


Spinorama EQ Score
JBL 4309 Score EQ Spinorama.png


Zoom PIR-LW-ON
JBL 4309 Zoom.png

Regression - Tonal flat On with EQ
JBL 4309 Regression - Tonal.png


Radar no EQ vs EQ score
Large improvements
JBL 4309 EQ Design.png


The rest of the plots is attached.
 

Attachments

  • JBL 4309 Raw Directivity data.png
    JBL 4309 Raw Directivity data.png
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  • JBL 4309 Reflexion data.png
    JBL 4309 Reflexion data.png
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  • JBL 4309 LW data.png
    JBL 4309 LW data.png
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  • JBL 4309 2D surface Directivity Contour Data.png
    JBL 4309 2D surface Directivity Contour Data.png
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  • JBL 4309 3D surface Vertical Directivity Data.png
    JBL 4309 3D surface Vertical Directivity Data.png
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  • JBL 4309 3D surface Horizontal Directivity Data.png
    JBL 4309 3D surface Horizontal Directivity Data.png
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  • JBL 4309 Normalized Directivity data.png
    JBL 4309 Normalized Directivity data.png
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  • JBL 4309 Horizontal 3D Directivity data.png
    JBL 4309 Horizontal 3D Directivity data.png
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  • JBL 4309 APO EQ Score 96000Hz.txt
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  • JBL 4309 Vertical 3D Directivity data.png
    JBL 4309 Vertical 3D Directivity data.png
    428.3 KB · Views: 28

napilopez

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On my PC now, here's how the LW and PIR compare.

Mine vs ASR 4309.png


Mostly quite similar. I seem to have summed the bass slightly too high perhaps, and there are some small differences here and there. but very similar overall.

Agreed.

Also the ability to play full range and loud. That seems to be just as (if not more) important as a great spinorama, and these speakers ace that part of the test, though the $25,000 amps may exaggerate this compared to what most ends users will actually get.

full range and loud enough* I'd say. Indeed it didn't feel like these were close their limit in my apartment with the requisite SPL limitations and all (plus my own quieter listening preferences)

Does it look better with the grill on?

Matter of taste. Nice thing is that the grille doesn't cover the tweeter, which is fairly protected simply by being so recessed into the waveguide.

Grille also has a negligible on the response (on-axis, at least):

4309-grille.png


Note the above is labeled wrong. Orange is with the grille, white is without. Not that it really matters.
 

napilopez

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By the way, here's how it compared to the similarly spec'd and priced HDI-1600 (my own measurements, just using those because I'd already made the graphs and they matched amir's closely too):

4309-v-hdi.png


Even though the response is more jagged, I think overall you're getting very similar tonal balance.

Part of the reason I preferred the 4309, which I tested right after the HDI-1600, is that I thought it imaged better. It's not evident from the spin alone, but despite the worse DI curves, the 4309 actually has slightly smoother horizontal directivity. Looking at the horizontal ER components we have:

4309:

4309-ER-Horizontal.png


HDI-1600:

HDI Horizontal ER.png


Note the Horizontal DI curve (yellow, bottom) and sidewall reflection curves (pink) in particular. The HDI-1600 has some bunching in the upper octaves that is not present in the 4309. It's very slight but I do think these differences are audible.
 
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Vovgan

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Back panel nods to audiophile market with bi-wire binding posts:

Chief, sorry for posting it once again but it would be really great to see the objective assessment of whether bi-amping makes any difference! Ideally on a good speaker like this one (distortion levels at the same high volume, SPL, maybe even frequency response?) Thanks!
 
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Inner Space

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Nice speaker. That Amir enjoyed it pre-EQ is possibly the billionth data point gathered over a century that might lead to a working hypothesis: within reason, frequency response doesn't matter very much. Perhaps the brain can post-EQ. Certainly we can hear subtle touch and nuance in musical figures - even though the in-room SPLs are violently doubling and halving (at best) through the octaves.
 

ROOSKIE

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Well, the spinorama captures all these things except for the "loud" part. It captures directivity/room interaction and bandwidth.

And, to be clear, with a medium sensitivity and a rolloff starting around 100Hz, I wouldn't consider this speaker full range. Not anymore full range than other bookshelf sized speakers with a single woofer. (look at the distortion take off <100Hz as you increase volume above 86dB) Though, they did try to push it lower by extending the port tuning ... looks like they tried using a Chebyshev alignment. *shrug*
To my eye harmonic distorion below 100hrz-40hrz @96db is excellent. Nearly all 2nd order.
3rd order @96 is very low. Barly touches 1%@50hrz and way below that the rest of the way.
3rd order on the tweeter is basically zero. Truly superb.
Yah, you get that 2nd order which seems to be typical for waveguide/horn loaded compression drivers no matter what the cost.
I think this is outstanding based on my experience and what I have gathered from others experience and research. I doubt any harmonic distortion is audible @96db above 35/40hrz.
Plus I am seeing 10db down in bass at 35/36hrz. Excellent. With room gain that will be wonderful in many rooms.
 

hardisj

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To my eye harmonic distorion below 100hrz-40hrz @96db is excellent. Nearly all 2nd order.
3rd order @96 is very low. Barly touches 1%@50hrz and way below that the rest of the way.
3rd order on the tweeter is basically zero. Truly superb.
Yah, you get that 2nd order which seems to be typical for waveguide/horn loaded compression drivers no matter what the cost.
I think this is outstanding based on my experience and what I have gathered from others experience and research. I doubt any harmonic distortion is audible @96db above 35/40hrz.
Plus I am seeing 10db down in bass at 35/36hrz. Excellent. With room gain that will be wonderful in many rooms.


I’m not saying it’s terrible. I’m saying it’s not necessarily better than I’ve seen in similarly sized speakers. I feel like some folks here are automatically assuming this speaker gets loud because it’s got the JBL Pro theme going. But with a sensitivity of 85dB and a limited bass extension it’s not going to break new ground. And the distortion data hints at that. In fact, this speaker is similar to the Kef R3 both in the extended shelf port design and the output capabilities (via lower frequency extension and HD metrics).

This JBL is a speaker that I think would be extremely interesting to see put in a DBT based on what the data is showing vs what the replies here are.
 

richard12511

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Preference Rating
SCORE: 3.7
SCOREw/ sub: 5.6


Sensitivity: 85.4dB (300Hz-3kHz ; spec: 87dB)
Frequency response: +/- 5.1dB 80Hz-20kHz


Damn, that's lower than I was expecting. I was expecting low 5s, mainly due to the excellent directivity(which is SOTA). Also, while there are a lot of resonances, the overall shape of the FR looks decent. I think good directivity is maybe more important than the Olive score gives it credit for. Very similar situation to the DIYSG horn that Erin measured awhile back.

Is this the lowest Olive score we've seen for a 5/5(Golf panther) rating?
 
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