This is a review and detailed measurements of the JBL AC25 "ultra-narrow" 2-way speaker. It is on kind loan from a member and costs US $1007.64.
I tested it with the grill in place as it is screwed to the front baffle. Still, I wish I had taken it apart before the measurements to get a better handle of driver locations and the three ports. The grill has black foam behind it that would not let me find the drivers even with a flashlight. Back panel is interesting in the way it has both screw terminals and SpeakOn:
I tested using the screw terminals.
The case is extremely solid and heavy especially for its size. You literally imagine it surviving a tank going over it!
As you see below, the frequency response was very poor and rough. I did not figure out why until I read the fine print on the spec sheet saying something to the effect of "FIR Turning." At first this did not make sense as this is a passive speaker and FIR is a DSP filtering method. It was not until I finished testing the speaker that I realized JBL provides a set of filters to be loaded into their DSP/DSP amps. I wish they had made this clearer. For this reason, there is no rating from me for this speaker as I didn't have a way to install said filters.
I eyeballed the location of the tweeter through the grill. And as noted, measurements are with the grill on.
NOTE: our company, Madrona Digital is a dealer for Harman products (and hence JBL) for custom integration business. So while there is no benefit to us one way or the other how this review goes, feel free to read whatever bias you want into my subjective remarks.
JBL AC25 Raw Measurements
As usual, we start with our anechoic frequency responses:
That is one rough frequency response and only makes sense in the context of active correction in upstream DSP/amplification with DSP. Here is the company spec which I assume is with DSP correction:
Without filtering, the early window and PIR don't make much sense but here they are anyway:
Horizontal beam width and directivity is not perfect but not bad either:
Vertically however we have dual woofers which beam at certain frequencies (same as MTM problem but in reverse):
The optimal listening angle will require some trial and error. The closer you sit to the speaker, the more exaggerated the effect becomes.
I was once again very surprised to see high distortion in JBL tweeters:
Impedance is fairly high which should make it easier to drive with longer cable runs:
Waterfall shows what I think is port resonances:
The trough by the way is due to cancellation at the height I had the microphone as explained just above.
And here is the step response:
JBL AC25 Listening Tests and Equalization
As I mentioned, I went into this testing without realizing the need for filters. The result was boomy sound with strange emphasis of some frequencies in mid-range. At first I did not want to attempt to develop a filter but took a shot at it anyway:
I tuned the response quite a bit to have a built-in room target (sloping down) as otherwise it sounded too bright. The brightness may have also been due to distortion in tweeter -- I can't be sure. But what is above, was a pretty good. Turning the filter set off caused a dramatic loss in fidelity with the sound becoming dull, boomy and lacking resolution. It simply dropped below what I could call "hi fi." Fortunately with the filter in place and dual woofer's power handling, I could crank this up without any sudden increase in distortion or bottoming out.
Conclusions
I realize this is almost half a review given the fact that I did not have access or even knowledge of the filters that go with the speaker. Still, I hope the measurements provide a good foundation for someone to develop their own EQ without the need to use JBL DSP products. Overall, I am impressed with power handling and solid packaging of the speaker.
I can't provide a recommendation one way or the other without evaluating the AC25 with its companion filtering. Wish the company would make this more clear in its marketing material.
-----------
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/
I tested it with the grill in place as it is screwed to the front baffle. Still, I wish I had taken it apart before the measurements to get a better handle of driver locations and the three ports. The grill has black foam behind it that would not let me find the drivers even with a flashlight. Back panel is interesting in the way it has both screw terminals and SpeakOn:
I tested using the screw terminals.
The case is extremely solid and heavy especially for its size. You literally imagine it surviving a tank going over it!
As you see below, the frequency response was very poor and rough. I did not figure out why until I read the fine print on the spec sheet saying something to the effect of "FIR Turning." At first this did not make sense as this is a passive speaker and FIR is a DSP filtering method. It was not until I finished testing the speaker that I realized JBL provides a set of filters to be loaded into their DSP/DSP amps. I wish they had made this clearer. For this reason, there is no rating from me for this speaker as I didn't have a way to install said filters.
I eyeballed the location of the tweeter through the grill. And as noted, measurements are with the grill on.
NOTE: our company, Madrona Digital is a dealer for Harman products (and hence JBL) for custom integration business. So while there is no benefit to us one way or the other how this review goes, feel free to read whatever bias you want into my subjective remarks.
JBL AC25 Raw Measurements
As usual, we start with our anechoic frequency responses:
That is one rough frequency response and only makes sense in the context of active correction in upstream DSP/amplification with DSP. Here is the company spec which I assume is with DSP correction:
Without filtering, the early window and PIR don't make much sense but here they are anyway:
Horizontal beam width and directivity is not perfect but not bad either:
Vertically however we have dual woofers which beam at certain frequencies (same as MTM problem but in reverse):
The optimal listening angle will require some trial and error. The closer you sit to the speaker, the more exaggerated the effect becomes.
I was once again very surprised to see high distortion in JBL tweeters:
Impedance is fairly high which should make it easier to drive with longer cable runs:
Waterfall shows what I think is port resonances:
The trough by the way is due to cancellation at the height I had the microphone as explained just above.
And here is the step response:
JBL AC25 Listening Tests and Equalization
As I mentioned, I went into this testing without realizing the need for filters. The result was boomy sound with strange emphasis of some frequencies in mid-range. At first I did not want to attempt to develop a filter but took a shot at it anyway:
I tuned the response quite a bit to have a built-in room target (sloping down) as otherwise it sounded too bright. The brightness may have also been due to distortion in tweeter -- I can't be sure. But what is above, was a pretty good. Turning the filter set off caused a dramatic loss in fidelity with the sound becoming dull, boomy and lacking resolution. It simply dropped below what I could call "hi fi." Fortunately with the filter in place and dual woofer's power handling, I could crank this up without any sudden increase in distortion or bottoming out.
Conclusions
I realize this is almost half a review given the fact that I did not have access or even knowledge of the filters that go with the speaker. Still, I hope the measurements provide a good foundation for someone to develop their own EQ without the need to use JBL DSP products. Overall, I am impressed with power handling and solid packaging of the speaker.
I can't provide a recommendation one way or the other without evaluating the AC25 with its companion filtering. Wish the company would make this more clear in its marketing material.
-----------
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/
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