This is a review and detailed measurements of the JBL 308P MKII 8-inch Monitor (powered speaker). I purchased this from a member a few months ago. New, they cost US $249.
The 3 series look the same for good or bad:
The large plastic waveguide is really in your face. Wish JBL would provide a matt version of it.
Back panel has the usual controls:
Drivers are powered using dual 56 watt class D amps. Crossover is stated at 1.8 kHz.
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 800 measurement which resulted in error rate of less than 1% throughout the range.
Temperature was 60 degrees F. Measurement location is at sea level so you compute the pressure.
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.
Reference axis was the tweeter center.
JBL 308P MKII 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:
I must say, this is a better response than I expected! On-axis is essentially flat from 45 Hz to above 15 kHz. There is a resonance near 20 kHz but most of us don't hear that high so probably OK. There is a tiny dip around 1.4 kHz. Measuring each radiating element tells us why:
As you see, there is a small "dead" region between the woofer and tweeter crossover region. I wonder if this sample variation. Regardless, if the woofer was 100 Hz higher or tweeter was 100 Hz lower, it would cover that gap.
Early window which is more representative of far field listening sums quite nicely as well:
Putting the two together, this is our predicted in-room far-field response:
Man this is good! It is very hard to get this kind of precision in a passive speaker.
Beamwidth and directivity are excellent:
Even vertically it is good compared to most 2-way designs:
You have ±20 degrees vertically before you get in trouble much.
The only downer is distortion:
During the sweep even with my ear protection on, I could hear anomalies at 96 dB. There is electronic limiter which when kicks in, creates all kind of noises and squeals.
Here it is in absolute level:
I could get it to produce around 105 dBSPL at 1 meter before it would severely limit levels (not shown).
JBL 308P MKII Listening Tests
Ah, what a joy this speaker is to listen to. It has plenty of warm and impactful bass, yet is almost perfectly neutral. I say if I had to listen to it for a long time, I might take down the highs just a bit but that is it.
Gradually turn up the volume with deep bass though and at first, everything sounds wonderful. When you get to pretty loud levels, the sound gets muddy at first before reaching quite distorted levels. It is not distortion you are used to due to limiter. But it is there. Suspecting it was very low frequencies that was giving it trouble, I dialed in this quick filter:
This is helped fair bit but also cost me a bit of that wonderful bass.
And oh, yes, there is hiss from the tweeter. It is very audible with your ear at the tweeter level but is gone at about 2/3 of a meter/2 feet or so. Turning down the gain reduces it a bit but note that this speaker does NOT want to have too much driving it. Setting the gain low and them pumping up the source generates severe distortion. Shame as this would be a good way to reduce the impact.
Conclusions
If you want to get a taste of accurate sound production that manages to delight, the JBL 308P MKii is a wonderful entry into this world. You would quickly learn that what research says about preference and accuracy being two sides of the same kind is very much true.
As with many powered speakers, amplification for the woofer is the limiting factor. This speaker with 100 watts or more to power the woofer would be so darn perfect. As it is, it will get quite loud and present ton of bass. Just don't expect miracles in overall loudness.
I am very happy to recommend the JBL 308P MKii.
------------
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/
The 3 series look the same for good or bad:
The large plastic waveguide is really in your face. Wish JBL would provide a matt version of it.
Back panel has the usual controls:
Drivers are powered using dual 56 watt class D amps. Crossover is stated at 1.8 kHz.
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 800 measurement which resulted in error rate of less than 1% throughout the range.
Temperature was 60 degrees F. Measurement location is at sea level so you compute the pressure.
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.
Reference axis was the tweeter center.
JBL 308P MKII 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:
I must say, this is a better response than I expected! On-axis is essentially flat from 45 Hz to above 15 kHz. There is a resonance near 20 kHz but most of us don't hear that high so probably OK. There is a tiny dip around 1.4 kHz. Measuring each radiating element tells us why:
As you see, there is a small "dead" region between the woofer and tweeter crossover region. I wonder if this sample variation. Regardless, if the woofer was 100 Hz higher or tweeter was 100 Hz lower, it would cover that gap.
Early window which is more representative of far field listening sums quite nicely as well:
Putting the two together, this is our predicted in-room far-field response:
Man this is good! It is very hard to get this kind of precision in a passive speaker.
Beamwidth and directivity are excellent:
Even vertically it is good compared to most 2-way designs:
You have ±20 degrees vertically before you get in trouble much.
The only downer is distortion:
During the sweep even with my ear protection on, I could hear anomalies at 96 dB. There is electronic limiter which when kicks in, creates all kind of noises and squeals.
Here it is in absolute level:
I could get it to produce around 105 dBSPL at 1 meter before it would severely limit levels (not shown).
JBL 308P MKII Listening Tests
Ah, what a joy this speaker is to listen to. It has plenty of warm and impactful bass, yet is almost perfectly neutral. I say if I had to listen to it for a long time, I might take down the highs just a bit but that is it.
Gradually turn up the volume with deep bass though and at first, everything sounds wonderful. When you get to pretty loud levels, the sound gets muddy at first before reaching quite distorted levels. It is not distortion you are used to due to limiter. But it is there. Suspecting it was very low frequencies that was giving it trouble, I dialed in this quick filter:
This is helped fair bit but also cost me a bit of that wonderful bass.
And oh, yes, there is hiss from the tweeter. It is very audible with your ear at the tweeter level but is gone at about 2/3 of a meter/2 feet or so. Turning down the gain reduces it a bit but note that this speaker does NOT want to have too much driving it. Setting the gain low and them pumping up the source generates severe distortion. Shame as this would be a good way to reduce the impact.
Conclusions
If you want to get a taste of accurate sound production that manages to delight, the JBL 308P MKii is a wonderful entry into this world. You would quickly learn that what research says about preference and accuracy being two sides of the same kind is very much true.
As with many powered speakers, amplification for the woofer is the limiting factor. This speaker with 100 watts or more to power the woofer would be so darn perfect. As it is, it will get quite loud and present ton of bass. Just don't expect miracles in overall loudness.
I am very happy to recommend the JBL 308P MKii.
------------
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/
Last edited:
Fixed.
