JBL AC25 Speaker Review

[EJ3]

It’s interesting. We see the same trend toward digital correction in cameras. Companies like Leica used to pride themselves on correcting everything in analog but it turns out that it’s much easier to do a good design that responds to digital lens correction.

The big problem is that we have tools like DANTE but not for copy protected sources. I have to wonder with music no longer copy protected and everyone on a subscription* and video moving toward subscriptions as well, might it be possible to drop copy protection in the future??

*(I, for one, love my physical media but it’s clear and exception to the mainstream today.)

I do like the form factor though. Nice and small!

I have yet to succumb to streaming (YET) and I will delay it as long as possible. When I do, it will be dedicated. The stereo will be in no way connected to anything else in the home.

 

[Shike]

Honestly I think this model was basically desperation to create the smallest thing in the line they could. My guess is they couldn't make a compression driver friendly guide for the footprint they wanted with the 5.25" drivers and unfortunately they cobbled a guide on that met dispersion/loading goals and that was the end of it. Nothing in this shows any semblance of smart engineering other than the fact it sort-of functions for application.

I believe the compression driver equipped ones in the AC series using the progressive transition guide are significantly better (AC26/28) - though am biased because I own them. They've never come off as "bright" or distorting, though they do required DSP. I used a target that appeared accurate for what the speakers were doing in room and just went that route, no CDi or anything like that.

Then again I got five speakers for under $1K so experimentation was encouraged. ¯\_(ツ)_/¯

EDIT:

Based on information found in the spec sheet I believe the speaker may be faulty - I'm no longer sure the above is correct but leaving it for posterity.

 

[notsodeadlizard]

But this is a professional series, the loudspeakers of this series are not sources of near field at all, this is for sounding restaurants and sports clubs, there are completely different requirements and quality indicators, why are they here?

 

[voodooless]

why are they here?

Why are any of us here…

 

[amirm]

But this is a professional series, the loudspeakers of this series are not sources of near field at all, this is for sounding restaurants and sports clubs, there are completely different requirements and quality indicators, why are they here?

Because it is pretty expensive for that kind of application and company shows pretty reasonable frequency response graphs, no doubt with DSP. They also say this: "High output, 2-way loudspeaker systems combining flexibility with high fidelity." This would be the description of what you want in a home theater.

 

[Shike]

Hmm, plot thickens? The spec sheet for the speaker can be found here and on the second page it says:

Measurements obtained in full passive crossover mode with no signal processing. Graphs are from unaltered measured data.

Sooo . . . something isn't adding up. In fact the spec sheet makes no mention of FIR filters at all. I might be going on a limb here saying this, but maybe there is something wrong with that tweeter or maybe there was an oversight in testing/documentation (on JBL's side)?

 

[notsodeadlizard]

Because it is pretty expensive for that kind of application and company shows pretty reasonable frequency response graphs, no doubt with DSP. They also say this: "High output, 2-way loudspeaker systems combining flexibility with high fidelity." This would be the description of what you want in a home theater.

The price is absolutely normal (even cheap) for the professional segment, for customers in this segment, sounding is not the most important detail and there are no large turnovers, but there are specific requirements. so prices are higher. It would be good to explain to people that this equipment is not for use at home at all and that the very concept of high fidelity can be and is different here.
It's a bad idea to use such an equipment not on purpose.

 

[amirm]

Hmm, plot thickens? The spec sheet for the speaker can be found here and on the second page it says:



Sooo . . . something isn't adding up. In fact the spec sheet makes no mention of FIR filters at all. I might be going on a limb here saying this, but maybe there is something wrong with that tweeter or maybe there was an oversight in testing/documentation (on JBL's side)?

Good find. In this case the owner should ask JBL what us going on.

 

[PeteL]

The price is absolutely normal (even cheap) for the professional segment, for customers in this segment, sounding is not the most important detail and there are no large turnovers, but there are specific requirements. so prices are higher. It would be good to explain to people that this equipment is not for use at home at all and that the very concept of high fidelity can be and is different here.
It's a bad idea to use such an equipment not on purpose.

I disagree, great PA speakers are good sounding speakers, You want Hi Fidelity as much as at home and the price has to be justified. They are not ultra expensive but not ultra cheap neither. those are just bad. No FOH engineer I know will be happy to have that to work with. In fact it's pretty well known that this serie from JBL are mediocre. I do other stuff now but still mix as a side line sometimes and we are happy when we get LAcoustic, D&B, Coda, even Nexo (Yamaha) If need be but you get a JBL PA, well, we'll do our best, but we know when we're in front of a good sounding PA. That's not it. Yes I agree that there are certainly other requirements and yes DSP is mandatory and it's not a problem in itself, but DSP will not fix something poorly engineered.

 

[fineMen]

In both cases, speaker defective or not: no, thank you. Is this JBL? Post production quality control, robustness with a pro product?

 

[GXAlan]

Good find. In this case the owner should ask JBL what us going on.

+1 for the owner.

JBL Pro support is good. I had a random question about the pops when the 708P switches sample rates and they were calling me and leaving phone messages to make sure my question could be answered. They were overly pro-active which I guess makes sense if they have some sort of metric of average time from service ticket creation to closure.

 

[Tom C]

+1 for the owner.

JBL Pro support is good. I had a random question about the pops when the 708P switches sample rates and they were calling me and leaving phone messages to make sure my question could be answered. They were overly pro-active which I guess makes sense if they have some sort of metric of average time from service ticket creation to closure.

Did you get a satisfactory answer? If so, please share!

 

[GXAlan]

Did you get a satisfactory answer? If so, please share!

They
1) acknowledged behavior and said that it won’t do it if you mute before changing sample rate. In most pro applications, sample rate changes are uncommon

(they made it sound like you could change the sample rate playing a 0dB track in the correct sampling rate and it would switch without the pop. Although as I am typing this up, maybe they meant on the unit itself).

2) you can theoretically damage the compression driver although it is very unlikely in practice since there are protections, but you can damage it. They kept emphasizing that I should not ignore the pop just because it didn’t bother me.

3) even if your volume is set to minus something dB so that there would be some headroom for presumably 0 dBFS, they still didn’t seem to like that as an option.

4) the recommended using analog input in applications with frequent sampling rate changes…

Back on track to this topic… we should try to find out what’s going on with this speaker!

 

[Shike]

Back on track to this topic… we should try to find out what’s going on with this speaker!

All I can say is this is really weird, I hope the owner has been notified to check/follow-up with JBL. If they have two of the same speakers and a umik it might even help just for a quick sanity check to compare samples in a rough manner to see if the FR/distortion is that wonky on both.

On the flipside I decided to pull out my umik and test my AC26 (a slightly bigger brother) but it uses a compression driver. No matter what height on-axis I couldn't get it to match JBL's FR. They do mention that they can change parts/parameters to improve products so who knows if there was a revision that changed it some. The good news is my measurements really aren't really different in a way that I would say the performance is worse, and even cranking them to ~95dB 1M had distortion typically below .5% on the tweeter and only approaching 1% once in a blue moon towards 200hz or so. Generally the FR is ragged on these being +/- 5dB, but FR isn't a huge concern IMO because DSP is expected.

So no idea on where that leaves the AC25.

 

[beagleman]

The Tweeter Impedance AND distortion are quite high between 4-6 Khz or so, and the output is fairly LOW at that point. (Amirs Measurements)

Does that give a hint as to what could be wrong?

JBL shows around 12-15 ohms in that region, Amir found it between 40-63 ohms....??
These are very high power handling and rated for up to 115 db output, I doubt distortion could be that high by design by even 86-96 db outputs.

 

[teashea]

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.
View attachment 276735

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:
View attachment 276736

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:
View attachment 276738

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:

View attachment 276739
Without filtering, the early window and PIR don't make much sense but here they are anyway:
View attachment 276740

View attachment 276741

Horizontal beam width and directivity is not perfect but not bad either:
View attachment 276742
View attachment 276743

Vertically however we have dual woofers which beam at certain frequencies (same as MTM problem but in reverse):

View attachment 276744

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:
View attachment 276745
View attachment 276746

Impedance is fairly high which should make it easier to drive with longer cable runs:

View attachment 276747

Waterfall shows what I think is port resonances:

View attachment 276748

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:
View attachment 276749

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:
View attachment 276752

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

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Another fine and helpful review - well done review for a rather poor speaker. Makes one appreciate comparably priced Neumann monitors.

 

[Lewzke]

This JBL is a joke. After Harman buyed AKG and JBL and many other audio companies they just destroyed the quality productions. Why? "To reduce expenses". This is just garbabe from engineering perspective.

 

[respice finem]

This JBL is a joke. After Harman buyed AKG and JBL and many other audio companies they just destroyed the quality productions. Why? "To reduce expenses". This is just garbabe from engineering perspective.

It"s a general "sickness" of our modern economy.
Making good yet affordable products is hard, selling more expensive ones is harder, and making them durable is in the way of "everlasting growth".
No growth, high cost = company goes broke or will be sold to "someone who will do it right"...