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!
It is like a half-scale version of a super car! Back panel nods to audiophile market with bi-wire binding posts:
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:
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:
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:
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:
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:
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:
Vertically naturally is not as perfect but still a lot better than many 2-way non-coaxial speakers:
Zooming into three frequencies, we see very good behavior as far as 3-D dispersion:
Crossover frequency is 1.6 kHz by the way.
When it comes to distortion, at 86 dB the 4309 is just cruising:
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 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:
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/
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!
It is like a half-scale version of a super car! Back panel nods to audiophile market with bi-wire binding posts:
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:
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:
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:
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:
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:
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:
Vertically naturally is not as perfect but still a lot better than many 2-way non-coaxial speakers:
Zooming into three frequencies, we see very good behavior as far as 3-D dispersion:
Crossover frequency is 1.6 kHz by the way.
When it comes to distortion, at 86 dB the 4309 is just cruising:
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 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:
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/
