JBL LSR305P MKii and Control 1 Pro Monitors Review

[amirm]

Amir: you can put in the graphics 10Hz, 20Hz ... 1000Hz. ?
Thanks for all the work.

I was going to but forgot.

 

[Midwest Blade]

Thank you for the layman tutorial, the explanations and examples were very informative. Great effort!

 

[garbulky]

Well, what convinced me Harman is onto something wasn't reading about their efforts. It was hearing some of their products. The mk 1 305s are outstanding for the price and commendably good in absolute terms. I needed some decent cheap monitors for recording I did. Many suggested them. It took 10 seconds to decide they completely outclassed Maudio BX monitors I had previously. This encouraged me to try some low end Revels for a video setup. Those were/are far better than I ever expected. It was only after that I began looking at what Harman's research indicated.

I don't doubt wrinkles will be discovered, but in broad terms I think they've headed things in the correct direction. I wish more work were done on panel speakers. Or if I could do the blind testing at Harman or a similar facility with some Revels and some ESL's maybe I'd be convinced.

Good to hear! The JBL speakers I've heard (their larger models) weren't too good. Perhaps their monitor line sounds great.

 

[amirm]

One is active, the other is passive.
But I am saying overall, not only these, to add difficulty to drive as a standard set of measurements.

I will be posting that for passives.

 

[Rockfella]

Congrats! This page will go down in audiophile history

 

[NTK]

Amir, first let me thank you and congratulate you on your effort (both in expenditure and time) to bring us this enormously valuable information to us.

I have one comment. Per my reading of ANSI/CEA-2034, section 5.1, the output of self-powered loudspeakers during test should be 79 dB SPL at the 2 m measuring distance, which I believe when corrected to 1 m in free field, is 85 dB SPL. Your graphs showed that the tests were conducted at about 20 dB SPL lower.

 

[LTig]

How would digital inputs work for speakers that are sold singly?

Two separate TOSLINK cables from your audio interface, one for each speaker? Or a whole bundle of them if you're mixing 5.1 / 7.1 / 7.2.2 / whatever?

My K&H O300D: AES IN (XLR) and then a BNC connector to feed the other speaker. A switch determlnes which channel is decoded. But I've never used it.

 

[amirm]

Is there any smoothing applied to those graphs? Or does the system take care of all that

I set it to 20 points per octave. Frequency measurements are at 0.7 Hz from what I recall.

 

[amirm]

Amir, first let me thank you and congratulate you on your effort (both in expenditure and time) to bring us this enormously valuable information to us.

I have one comment. Per my reading of ANSI/CEA-2034, section 5.1, the output of self-powered loudspeakers during test should be 79 dB SPL at the 2 m measuring distance, which I believe when corrected to 1 m in free field, is 85 dB SPL. Your graphs showed that the tests were conducted at about 20 dB SPL lower.

View attachment 45333

I should have noted that the absolute SPL numbers are not correct. Working on fixing that. Audibly they would be at level you would use them.

 

[oivavoi]

I've been meaning to ask - how would designs like dipole and omnidirectional speakers relate to the work of Toole, Olive, etc?
.

When it comes to omnis at least, they can easily be measured using the Toole/Olive/Harman metric. By logic well-designed omni speakers are the ones which will score the highest when it comes to accordance between the direct sound or listening window and the early reflections and/or total sound power. I don't think Harman has done any tests with omnis, but at the NRC in Canada - where Toole worked before moving to Harman - the speaker that received the highest ratings ever was a quasi-omni speaker from Mirage.

Same thing applies to dipoles I would think, the back wave becomes indirect sound in the measurements, even though it's out of phase relative to the direct sound.

The only thing that is tricky when it comes to direct blind comparison though is that omnis and dipoles can be more finicky about placement than conventional speakers, so if they are not given enough air they will often perform worse than conventional speakers. Søren Bech showed this is one of his studies . Conventional speakers performed better close to the wall, omni and dipole speakers performed better well away from the wall.

At the same time, there are people who don't like omnis, even though the indirect sound is closer to the direct sound than with conventional speakers. And some people, like me, really like omnis. This indicates to me that accordance between direct and indirect sound is not the only thing that matters. It also matters whether directivity is wide or narrow - and I do believe that this is partly a matter of preference.

 

[Darkweb]

Good to hear! The JBL speakers I've heard (their larger models) weren't too good. Perhaps their monitor line sounds great.

Never trust your ears, only the graphs and other people’s listening preferences!

 

[Bob Carter]

How do we know if the SINAD of the internal electronics is any more than 55dB from this review? And if SINAD of the electronics doesn't matter from the speakers, does that mean the AP 555 is up for sale, and all the electronics reviews were worthless? I'm a bit confused here guys.

 

[Severian]

I would love to see this in general as a part of the test suite! A lot of studio monitor makers, like JBL themselves, give some data on that. But of course it would be good to see tested especially for non-studio gear where nobody knows what the values even remotely are.



This would be a dream come true. I don't know of any measurements for it on the speaker side of things.

I have a belief, possibly totally wrong, that it's pretty key to how we perceive the speakers subjectively and how much detail they convey.

I have a related belief on the amplifier side of things but more knowledgable folks always wave it off. They tell me blahblahblah slew rate blahblah damping factor and that these aren't important past a certain point. Seems to me that they would be. But, I'm a dummy.

It wouldn't necessarily be a repeatable test protocol, but it would be pretty interesting to see, e.g., a "low output" controlled directivity speaker such as one of these JBLs measured at a few representative SPLs alongside a "high output" example such as a PA speaker with a solid reputation for fidelity (not my wheelhouse, but I always read good things about the QSC K series), a DIY speaker from from the "econowave" school, or a JBL cinema speaker.

Maybe we wouldn't be able to make predictions about listener preference, but I bet we could learn a lot anyway.

 

[Juhazi]

I should have noted that the absolute SPL numbers are not correct. Working on fixing that. Audibly they would be at level you would use them.

Fine, but still spl with 2,83V is way too low to show distortion. NCR does 90dB at 2m and 95dB for biggies, which is somewhat minimum to see any significant distortion problems of hifi-speakers. For passives drive voltge varies in 3x range for this spl! Actives must be set to certain spl/F/1m. Anyway, to get meaningful comparison, I suggest using standard eg. 95dB/1m at 1kHs sine spl for all. Also 100dB/1m for large speakers.

 

[GD Fan]

This is really exciting. (And it saved me from utter boredom at the office today!) Not only is this perhaps the most useful speaker review ever published, it was also so skillfully articulated that I understood most of it as a layperson. But I'll definitely give it another read to be prepared for future postings. (Having just upgraded speakers last fall I may be nervous as the subject of each new review is unveiled...)

 

[Bob Carter]

How do we know if the SINAD of the internal electronics is any more than 55dB from this review? And if SINAD of the electronics doesn't matter from the speakers, does that mean the AP 555 is up for sale, and all the electronics reviews were worthless? I'm a bit confused here guys.

Even more concerning is this review has 120 likes and 134 posts so far, and nobody else has wondered the same.

 

[napilopez]

Thank you for the interesting content.

1.) I'm not suggesting that the metric I outlined would be a general performance indicator or that it should on its own be used to create a ranking. I qualified it further by restricting its usefulness to people willing to use equalization. To those people however, such a metric would be highly useful.

2.) I'm not suggesting to rate the differences between the listening window and early reflections curves. Clearly there can be no universal standard of an ideal drop-off: Some may prefer a steeper drop-off and narrower directivity, others a more gentle drop-off and wider/more diffuse directivity.

3.) What I've been trying to suggest is to measure the evenness of the drop-off (whatever it may be) between the listening window and early reflections curves across the frequency spectrum. Followin Amirs explanations, everybody should want the early-reflections curve to track/run parallel to the listening-window-curve, irrespective of one's preference for wider or narrower directivity.

4.) It seems at least worth exploring whether such a metric combined with others would allow us to contruct a simple graphical representation of a speakers overall performance, that would a.) be indicative of actual performance in most contexts and b.) be easily readable by interested novices not familiar with audio science. For that purpose I suggested radar diagramms.

PS 1: Now to fully expose how unfamiliar I actually am with speaker design, from simply visually inspecting the curves you posted, the Rega's early reflections curve seems to most closely track the on-axis curve, which... would seem to fit the preference distribution... What am I getting wrong here?

PS 2: To illustrate: Imagine I printed and cut out a a number of on-axis curves without anything else and without db-scale. Just the curves themselves without context. Imagine I then printed and cut out the early-reflections curves of the same speakers, again without anything else and without db-scale. Now I would lay all those cut out curves out on a table. If the speakers had been well designed in this regard, I should easily be able to identify matching pairs of curves, without having any need for a db-scale. The absolute drop-off wouldnt matter - and it wouldnt matter in the metric I propose. Only the closeness of tracking would be evaluated.

All Fair points! I didn't meant to shut down your idea either, so I hope I didn't come off that way. I just wanted to make clear that when comparing two different speakers, things get more complicated.

But yeah, as long as its made clear to readers that they shouldn't take the even-ness of the early response curve as an absolute when comparing to other speakers, I'm fine with it.

I bet if the listening room was narrow, the speaker with wider dispersion would not be as preferred. It's situation dependent, which is why I don't think directivity past the listening window should be factored into a sonic quality score.

My impressions from reading Dr Toole's book and a few of the studies is that preference tend to be more a matter of use case and even individual preference than the space being tested in. This is something that definitely needs more research though.

Anecdotally, I have a very narrow listening room(13ft) - my speakers are only about 2-3 feet from the sidewalls - and I almost universally prefer wide-directivity designs for regular listening, despite always thinking I'd have preferred narrower designs. Narrow designs tend to have more pinpoint soundstage and more flexibility for adjusting the sound with placement, but I end up preferring the more expansive sound of wide designs. All sighted individual opinions of course, so not of much scientific value, but just some context for where I'm coming from.

I'd like to agree with you having owned and loved Quad ESL63 speakers, and liking panels. But I'm not reading those graphs to indicate the Quad looks better. It would appear Quads look worse except above 10 khz. I would have looked at those graphs and predicted Quads to finish last. Quad ESL 63s were designed as something of a quasi-point source, and seem to get close to it over the midrange at least. Less so above about 11 khz.

The Quads' off-axis response is ragged as hell there. Objectively not good in that regard.

But... it's like 10 or 20dB down compared to the other speakers' off-axis sound. The off-axis response is worse but you are barely hearing it. It is hardly interacting with the room compared to the other two.

Subjectively this matches up with what I heard when I got to spent a little while listening to them.

The quad is 'messy' but it's pretty well established that evenly spaced high-Q errors, especially in the treble, are less audible than wide, low q problems, which both of the other speakers exhibit. Similar to the errors we see on axis with coaxial speakers, a big reason we take averaged measurements in the first place. Granted, the ESL's peaks and dips are quite tall, but I'd be willing to bet they'd average out significantly.

So my guess would be the quad has better off-axis performance. But that's also what Dr Toole says right in the chapter so obviously that's what I believed:

"In Figure 7.12 the higher broadband directivity of the ESL 63 results in lower level first-order lateral reflections than either of the cone and dome designs. Both cone and dome systems exhibit fairly unattractive off-axis performance compared to the electrostatic system." And: "Earlier it was speculated, based on current understanding of loudspeaker measurements, that the Quad might have had an advantage in terms of sound quality, or at the very least, not a disadvantage. That speculation was not borne out. For the same reason, the notion that early lateral reflections in the listening room would be audible problems was not reinforced."

Anyway, it's section 7.4.2 of the book, if anyone wants to check in for themselves. Ultimately it's just one study. I would much like to see a similar test repeated with modern speakers that have cleaner off-axis performance and more polar data.

That's why I keep bringing up the M2 vs Salon2 example, which I know I've touched upon with @Blumlein 88 on another thread. To recap for everyone else, here's the spinoramas for the JBL M2:

And here's the Revel Ultima Salon2:

The M2 has 'prettier' curves, but the Salon2 won by 80:20 and 65:35 ratios in two double-blind listening sessions with 15 listeners. Wider directivity and maybe a cleaner ERDI curve seem to be the reasons. I wonder how the listening session would have fared with mixing engineers or in different spaces.

Anyway, just a friendly reminder to everyone in this thread that the prettier curve isn't necessarily the better one =]

 

[amirm]

Fine, but still spl with 2,83V is way too low to show distortion. NCR does 90dB at 2m and 95dB for biggies, which is somewhat minimum to see any significant distortion problems of hifi-speakers. For passives drive voltge varies in 3x range for this spl! Actives must be set to certain spl/F/1m. Anyway, to get meaningful comparison, I suggest using standard eg. 95dB/1m at 1kHs sine spl for all. Also 100dB/1m for large speakers.

I want to make sure this is clear. The Klippel robotic system (NFS) is designed for near field amplitude/frequency response measurements. As such, I have the microphone situated to cover that area (inches from speaker). To go to 1 meter+ from speaker requires re-adjustment of the boom and which is a pain currently. It screws all the system calibration and adjustment requires tools.

Distortion/compression, etc. are not applications for the robotic part of the system. So it becomes a different project, potentially requiring a different setup altogether. The base analyzer in Klippel (KA-3) is capable of doing this but the rest of the setup is not optimal.

 

[jtwrace]

I want to make sure this is clear. The Klippel robotic system (NFS) is designed for near field amplitude/frequency response measurements. As such, I have the microphone situated to cover that area (inches from speaker). To go to 1 meter+ from speaker requires re-adjustment of the boom and which is a pain currently. It screws all the system calibration and adjustment requires tools.

Distortion/compression, etc. are not applications for the robotic part of the system. So it becomes a different project, potentially requiring a different setup altogether. The base analyzer in Klippel (KA-3) is capable of doing this but the rest of the setup is not optimal.

Can we see a picture? Without knowing how the system all works it's tough to give any recommendations. However, can you not make some sort of sliding mic boom with a ball screw or linear actuator? Then you can take a laser measurement and just set it to that distance or write some code and make it automated.

 

[napilopez]

How do we know if the SINAD of the internal electronics is any more than 55dB from this review? And if SINAD of the electronics doesn't matter from the speakers, does that mean the AP 555 is up for sale, and all the electronics reviews were worthless? I'm a bit confused here guys.

Even more concerning is this review has 120 likes and 134 posts so far, and nobody else has wondered the same.

Electronics reviews are important, especially as a way to cut through all the fluff in the industry. But yes, the speakers are way, way more important components, plain and simple. The vast majority of whether one setup sounds better than the other can be determined by the final frequency response and directivity leaving your speakers, so long as your amp has enough power.

I don't know if anyone has come up with value for how much electronics matter to final perception of acoustics, but I'm willing to bet it's less than 5 percent (obviously a made up figure, but just making a point).

While it might be an interesting thing for Amir to explore the internal electronics, it's probably not the most useful endeavor if virtually no consumer will ever open up their speakers and change the internal dac and amps.