JBL AC25 Speaker Review

[MAB]

Yes, also noticed that, seems to be not a typical HD source.

Yes, I don't understand the tweeter distortion. Previously tested JBL with elevated tweeter distortion (like the 708 series, or the M2) have elevated distortion at the resonance frequency of the tweeter. JBL rolls these off at the tweeter resonance using a filter in conjunction with the tweeter's mechanical rolloff. 708P for instance reviewed at ASR with my text on the tweeter resonance added:

This results in a 2nd HD peak at the resonance, which is roughly the shape of the impedance peak at resonance. I was initially confused on what JBL is doing on the 708 and M2. The thing is, both are really great sounding speakers. Whatever the audibility of the 708's distortion, the performance of the horn is magnificent, and I really can't hear the distortion, perhaps I am not perceptive enough.

The AC25 tested here looks broken with a train of even and odd HD components:

And if it isn't broken, certainly not the same as some of the other JBL tweeter distortion. And if this is performing as expected, the tweeter gonna make some square waves out of your signal. I do think something is very broken here though...

 

[Tom C]

We’ve seen a similar rise in distortion in the treble region before, in measurements of speakers with horn tweeters. I don’t know enough about speaker design to answer why, but I wonder if it’s the expected distortion generated by the throat of the horn. That would be second harmonic, and dependent on the length and diameter of the throat. And seems not to rise proportional to SPL increase, as we see here.
I’m sure someone here knows this answer.

 

[MAB]

We’ve seen a similar rise in distortion in the treble region before, in measurements of speakers with horn tweeters. I don’t know enough about speaker design to answer why, but I wonder if it’s the expected distortion generated by the throat of the horn. That would be second harmonic, and dependent on the length and diameter of the throat. And seems not to rise proportional to SPL increase, as we see here.
I’m sure someone here knows this answer.

Yes indeed, the M2 also shows exactly what you mentioned. 2nd HD matching the tweeter's resonant impedance peak...

This AC25 is totally different, and not the predicted 2nd order peak, I agree with your observations...

 

[FrantzM]

Thanks ! I was wondering why they would make a speaker like this. But the target market "houses of worship, presentation suites & retail are more often than not used by people that never heard of DSP. A lot of of those places are used by a lot of different groups with different needs in a PA. Not sure where the DSP comes in the chain but if it's a button you can press or mess with I can guaranty these will sound like crap 90% of the time.

The market for House of Worships AV system is vibrant teeming with contractors. They do know what DSP is. Make no mistake about it: these systems do present more than a modicum of fidelity to a large assembly in acoustically challenging spaces. Think about how much echo there is in most churches and how many people you need to reach...

I would not use such speaker in a home AV, but it has its use and purposes.

Peace.

 

[Chr1]

They look similar to some JBLs I have.... tho mine have a MTM layout and are sealed.

I bought eight of these JBL MS26s several years ago second hand as they seemed like a good deal as they were relatively expensive when new and seemed well built. Thought that they might make excellent surround speakers. Haven't measured them but had a quick listen to test they were functional and wasn't particularly impressed. Obviously they were not EQd and as previously mentioned, like most modern PA passives, they are made for use with subs and EQ. As also mentioned, they are obviously made for big SPLs and, not sure about a tank, but I'd bet you could run over it with pretty much any pneumatic tyred vehicle to no ill effect....chipped paint aside obviously.

 

[sarumbear]

@amirm no disrespect to you but you are doing a disservice to speakers like this. I appreciate your work immensely but you really must learn what a speaker is designed for and then test. Otherwise, your tests is simply giving the wrong message. Whether you recommend or not, does not cover it. We all want ASR to be THE source for test but tests must be done correctly.

Once again, no disrespect to you or what you are achieving.

 

[FrankW]

I appreciate your work immensely but you really must learn what a speaker is designed for and then test.

While I think the tweeter on this sample may be broken, please do share with us what tests Amir either did incorrectly or didn't do. Thanks.

 

[sarumbear]

While I think the tweeter on this sample may be broken, please do share with us what tests Amir either did incorrectly or didn't do. Thanks.

Testing it without the required EQ.

 

[amirm]

Testing it without the required EQ.

There is no mention of EQ being required in the documentation for the speaker. Nor did the owner tell me about it. Testing without EQ allows you to use it with other DSP solutions than that of JBL/Crown. All of this was mentioned in the review so no one is going to be misled.

The alternative would have been to not show you this review at all.

As it is, you are getting insight into the distortion and directivity of the speaker which are not impacted by the filtering.

Remember, the opportunity cost of testing a speaker is about $2,000. Throwing away such an assessment takes a lot of motivation than what you are mentioning.

 

[amirm]

While I think the tweeter on this sample may be broken, please do share with us what tests Amir either did incorrectly or didn't do. Thanks.

I have listened to it pre/post EQ and I detected nothing that would say the tweeter is broken. Harman measurements shows the same resonant peak as mine between 10 and 20 kHz. Very hard for both of these to happen and the tweeter being broken.

 

[FrankW]

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

I have listened to it pre/post EQ and I detected nothing that would say the tweeter is broken. Harman measurements shows the same resonant peak as mine between 10 and 20 kHz. Very hard for both of these to happen and the tweeter being broken.

True, but your measurements seems to match Harmans very well in the woofer range, then not at all in the tweeter range...except the resonance. Then there is the really strange high distortion...in the tweeter only range. My money is on a faulty tweeter in this sample

 

[LouB]

The market for House of Worships AV system is vibrant teeming with contractors. They do know what DSP is. Make no mistake about it: these systems do present more than a modicum of fidelity to a large assembly in acoustically challenging spaces. Think about how much echo there is in most churches and how many people you need to reach...

I would not use such speaker in a home AV, but it has its use and purposes.

Peace.

Yeah I'm sure of that. And theres always 2 sides of a coin. I have no doubt these littel speakers with DSP would be great. But I've preformed & used house PA's in palces of worship & different multi use facilitates with a house PA that were bought & set by people who seem to never be around when the venue is rented or used by a 2nd or 3rd party. A lot of charitable organizations don't have the money for a "sound man" & own PA system that is used (and abused) by a lot of different groups.
I only bring this up as Amir stated He didn't even realize these speakers needed DSP to work right, than reading JBL's marketing page it brought back memories of us spending time Un-effing a House PA that a prior user left it unusable for live music.

 

[GXAlan]

Throwing away such an assessment takes a lot of motivation than what you are mentioning.

+1 for Amir.

I find this article super helpful. If you look at the 708i for example, you can get away with a simple two point parametric EQ to get something decent. This means that you could use it with an AVR and the standard correction is probably going to be decent.

What we don’t know, until we have this data, is if these speakers would have worked similarly. Maybe the FIR takes you from a B+ to an A. In this case, we REALLY see that it is an issue and these cannot be used with a fancy FIR filter and it potentially may not be great beyond the midrange region maybe as speech boost.

 

[PeteL]

Yeah I'm sure of that. And theres always 2 sides of a coin. I have no doubt these littel speakers with DSP would be great. But I've preformed & used house PA's in palces of worship & different multi use facilitates with a house PA that were bought & set by people who seem to never be around when the venue is rented or used by a 2nd or 3rd party. A lot of charitable organizations don't have the money for a "sound man" & own PA system that is used (and abused) by a lot of different groups.
I only bring this up as Amir stated He didn't even realize these speakers needed DSP to work right, than reading JBL's marketing page it brought back memories of us spending time Un-effing a House PA that a prior user left it unusable for live music.

Normally the Integrator will password protect the DSP preset baked in the amp. No one has to touch that after Install. If you want to be creative with EQ there's plenty of that in the sound console.

 

[stevenswall]

Is this a trend we are seeing today?

Speakers intentionally designed to be used with DSP... and therefore, the core frequency response becomes almost irrelevant - it becomes all about how it behaves at different SPL's (distortion issues), resonances, and dispersion pattern.

That makes me wonder what a Genelec 8000 series would sound like with a passive crossover and no DSP. If I'm not mistaken they can contour the output of the active crossovers and all of their 8000 series speakers feature that. I'd like to believe that even their unEQed response wouldn't be as bad as this JBL with the crazy distortion and the dispersion should be better too.

 

[dasdoing]

that looks indeed strange.
someone can look at their graphs via GLL viewer: https://jblpro.com/en-US/site_elements/ease-spk-dll-files-full-jbl-pro-line
I have a somewhat similar speaker, but with compression driver and 2x6,5". why would you do this one with a dome tweeter?

 

[sarumbear]

There is no mention of EQ being required in the documentation for the speaker. Nor did the owner tell me about it.

With no disrespect to you but you are a HK dealer. Other dealers had identified how this speaker should be used. There is no reason why you couldn't either as you have the the ear of to the manufacturer and have access to their white papers.

The Application-Engineered (AE) series is an extensive range of permanent installation speakers with models found in almost any scenario, including (but not limited to!) performing arts venues, houses of worship, sports facilities, corporate boardrooms, cinema, bars and clubs.

Our Guide to JBL AE Compact loudspeakers

… - read more on Sound Technology Ltd

www.soundtech.co.uk

FIR (Finite Impulse Response) tunings provide linear-phase filtering, which optimizes frequency response and phase response independently and to a finer degree of precision than is possible with standard IIR (Infinite Impulse Response) “parameter-based” filters. The result is overall enhanced loudspeaker sound quality and improvements in coverage pattern consistency.

https://jblpro.com/en-US/site_elements/instructions-for-ae-series-fir-tunings

Remember, the opportunity cost of testing a speaker is about $2,000. Throwing away such an assessment takes a lot of motivation than what you are mentioning.

I do realise that and I for one am indebted to you for doing what you do. You elevated ASR to a reference level. I am simply trying to explain to you that presenting speakers as per their intend usage is important. Yes, you have explained in the text but the charts are there to be used unrelated to the text and they show a terrible speaker, which is not necessarily the case.

Allow me to repeat, what I am saying is simply to help to elevate your work and possibly to avoid ondue criticism you may get. It is a constructive criticism.

 

[Peafowl]

The World of ProAudio changed a lot in comparison to Home HiFi.

Every bigger brand like d&b audiotechnik, Danley Sound Labs, Meyer Sound, Cody Audio, APEX, ...
They use all amps with integrated DSP software and a big database with presets for their speakers. Some are open for other brands Like Powersoft armonia, but mostly you will read things like
" *only use this Loudspeaker with factory filter presets, available on our system amps."

 

[Thunder22]

With no disrespect to you but you are a HK dealer.
Allow me to repeat, what I am saying is simply to help to elevate your work and possibly to avoid ondue criticism you may get. It is a constructive criticism.

When somebody begins with " With no disrespect". They are about to be disrespectful. With no disrespect, please proofread your posts.

 

[amirm]

With no disrespect to you but you are a HK dealer. Other dealers had identified how this speaker should be used. There is no reason why you couldn't either as you have the the ear of to the manufacturer and have access to their white papers.

Nothing in the marketing material for this speaker makes it clear that DSP is required as you claimed. At best it says this in the link you provided for the full line:
"The new JBL Professional FIR (Finite Impulse Response) Tunings for the AE-Series provide further enhanced performance for the premium installation loudspeaker line. "

Further enhance performance is not remotely the same as DSP being mandatory. And no, as founder of Madrona Digital, I am not engaged in any projects or have day to day contact with any JBL or Harman employee. Your expectation that I should have known this and that as a result is out of line. There is no way for me to know the entire line of JBL products including these specialized products. If you don't like the review, just move along.