JBL LSR305P MKii and Control 1 Pro Monitors Review

[Severian]

Great review @amirm . I absolutely love my pair of JBL 306P's. I am def looking forward to more of your speaker reviews.

Would you be able to add compression sweeps to your test suite? It would be nice to see how a speaker's frequency response and distortion levels change as SPL's rise. And to pin point what the Max SPL of a speaker is so we can determine the size of a room and the type of content (music/HT) that speaker can faithfully reproduce.

Similar to what https://data-bass.com/ does for testing a subwoofer's output capability.

Yes - getting a handle on output capabilities would be fantastic. That is something that you don't get from spinorama data. It seems like it would be quite difficult to pinpoint an optimal max SPL, but perhaps it would be possible to test, say, the on-axis response at a few different SPLs to get an idea?

Or perhaps we can devise a test to get at the thorny issue of speaker dynamics?

 

[Digital Mastering System]

Congratulations Amir for publishing a fine speaker review! The first of many I hope.

 

[JohnBooty]

306p also seem to have some weird dip around the crossover frequency:

Spoiler: Digital Stereophony

View attachment 45306

Spoiler: Joe N Tell

View attachment 45307

Interestingly, JBL advertises the 306P as "47Hz – 20kHz (±3dB)" despite this which doesn't quite jive with those guys' (who I trust) measurements.

As bad as that looks in the measurements, I haven't found it to be a problem in reality. It's a narrow dip and we know that high Q dips like this are minimally audible. Also crucially, it's well out of the vocal range: half an octave above the soprano range. It's not even particularly egregious sounding in frequency sweeps.

I don't mean to defend it; it makes me say "wtf?" every time I think about it. Just giving my subjective opinion of the actual impact on music enjoyment which is pretty much nil.

It could be correctly said that the 305P is a better speaker than the 306P because of this. However, I think most would still prefer the 306P for enjoyment purposes. More bass extension and a slightly more powerful amp. At the very least, I wouldn't write the 306P off if anybody's in the market.

Note for clarity: Sorry for the sidetracked convo; these are the 306P and not the 305P that Amir measured. (But is is hopefully relevant; anybody considering the 305P would probably want to consider the 306P as well)

 

[napilopez]

(Hey guys! I just registered for this account after being a daily lurker for more than half a year. Even though I feel like I'm out of the speaker market myself (I got an amazing deal on some Technics SB-R1), there's always a buddy or relative that needs advice. More generally, the entire audio world is in dire need of some clarity.)

The proximate reason I created this account is because of the wishes for an easily digestible and hierarchically rankable numeric value for each speaker measured (comparable to the electronics SINAD metric). Now I understand that there is no single such metric that could encompass the totality of a speakers performance - especially because of the differing preferences regarding narrow/broad listening windows among buyers, the varying rooms those speakers will have to fit into and the willingness of buyers to EQ.

However, if I understood Amirs explanations of the various plots correctly, there seems to be one metric which could be transformed into a simple numeric value and which would be unambiguously desired by all prospective buyers open to the idea of equalizing the speakers (which I suspect is a sizeable and ever-expanding percentage of ASR readers): the relation of the amplitude-frequency-curve within the listening window and the amplitude-frequency-curve of the early reflections.

Imagine you sample both curves n times at corresponding intervals.
Then you subtract the sampled values of the early reflections from the sampled values of the listening window at the same frequencies.
You get n numer of difference values.
(Ideally, you'd want all those difference values to be equal: No matter how crooked the curve within the listening window is, if the early reflections curve tracks it precisely (by whatever offset), you can then fix it in EQ.)
So then you calculate the inequality among all the difference values. I'm not familiar enough with the mathematics to know which measure would be most suitable here. Perhaps a Gini coefficient or similar measurement could be adapted to produce one simple to understand number that would then tell us how amenable to speakers are to equalization - irrespective of how fucked up the unequalized curves look. You could call it the FBEQ-metric (fixable by equalization) and design a nice hierarchical ranking using it.

Going beyond this suggestion... while one value cannot encompass the totality of a speaker's performance, maybe a set of five or six such values could? For example: How amenable is it to eq? How linear is it withing the listening window without eq? What's the -6db point in the low frequencies? etc. If we could come up with a set of such metrics that could individually be transformed into numeric values, we could then build radar charts that would enable at-a-glance assessments of the general outlines of a speakers performance.View attachment 45290

I hate to be a stickler but I'm afraid to say that metric you proposed, about the difference between the early reflections curve and the listening window, would likely not be unambiguously preferred...

For example, some research suggests that a speaker with uneven dispersion (and thus, an uneven early reflections curve) will be preferred to a speaker with better off-axis performance if the former has wider dispersion. I've posted this previously on this forum but one of Toole's studies put up three speakers with even (for the time) on axis performance and varying off axis performance.

In this example, the Quad ESL clearly has the most even off axis response that is most timbrally similar to the on axis curve. The KEF and Rega both show significant differences. We'd probably call that off-axis performance straight up bad if these were modern speakers.

And yet, the Quad ends up worst in listening tests.

We saw something similar with the blind test comparison of the JBL M2 vs Revel Salon2. The Salon won by a considerable margin despite the M2's on axis and off axis performance both being much 'prettier' than the Salons.

Moreover, other research tells us that mixing engineers have a greater preference for narrow directivity designs and/or fewer sidewall reflections while doing their work than do recreational listeners and even mastering engineers, so that's another confounding factor. And individual preferences still exist in this regard.

Also note a timbrally balanced speaker with tall, narrow peaks and dips is likely to perform better than a speaker with a big shallow scoops across various frequencies.

While I'd love to see a universal preference metric as much as everyone, creating one really is a monumental task. Not saying it can't be done though or that we can't get to a useful approximation, just explaining some of the hurdles. With DACs and Amps we have some very clear goals for performance, and we largely know the limits of what's audible. With speakers, we are chasing a moving target.

Id still like to see information like standard deviation from a target curve and such, but we need to have an understanding that diminishing returns and preference have a role to play.

I'm sure Amir's conversation with Sean Olive will be fruitful though.

 

[garbulky]

I'm quite skeptical of a good sounding speaker from JBL. Congrats on your first review!

 

[q3cpma]

Hurray for the first speaker review! As already said, cumulative spectral decay (which encompasses group delay) like what SAR or Adam (https://www.adam-audio.com/content/uploads/2019/05/T5V_Spectogram.png) give is missing. That THD graph is pretty useless at such an anemic level too.

 

[JohnBooty]

Yes - getting a handle on output capabilities would be fantastic. That is something that you don't get from spinorama data. It seems like it would be quite difficult to pinpoint an optimal max SPL, but perhaps it would be possible to test, say, the on-axis response at a few different SPLs to get an idea?

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.

Or perhaps we can devise a test to get at the thorny issue of speaker dynamics?

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.

 

[MZKM]

I hate to be a stickler but I'm afraid to say that metric you proposed, about the difference between the early reflections curve and the listening window, would likely not be unambiguously preferred...

For example, some research suggests that a speaker with uneven dispersion (and thus, an uneven early reflections curve) will be preferred to a speaker with better off-axis performance if the former has wider dispersion. I've posted this previously on this forum but one of Toole's studies put up three speakers with even (for the time) on axis performance and varying off axis performance.

View attachment 45309

In this example, the Quad ESL clearly has the most even off axis response that is most timbrally similar to the on axis curve. The KEF and Rega both show significant differences. We'd probably call that off-axis performance straight up bad if these were modern speakers.

And yet, the Quad ends up worst in listening tests.

View attachment 45311

We saw something similar with the blind test comparison of the JBL M2 vs Revel Salon2. The Salon won by a considerable margin despite the M2's on axis and off axis performance both being much 'prettier' than the Salons.

Moreover, other research tells us that mixing engineers have a greater preference for narrow directivity designs and/or fewer sidewall reflections while doing their work than do recreational listeners and even mastering engineers, so that's another confounding factor. And individual preferences still exist in this regard.

Also note a timbrally balanced speaker with tall, narrow peaks and dips is likely to perform better than a speaker with a big shallow scoops across various frequencies.

While I'd love to see a universal preference metric as much as everyone, creating one really is a monumental task. Not saying it can't be done though or that we can't get to a useful approximation, just explaining some of the hurdles. With DACs and Amps we have some very clear goals for performance, and we largely know the limits of what's audible. With speakers, we are chasing a moving target.

Id still like to see information like standard deviation from a target curve and such, but we need to have an understanding that diminishing returns and preference have a role to play.

I'm sure Amir's conversation with Sean Olive will be fruitful though.

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.

 

[Jaimo]

Great stuff Amir...This is an excellent development - properly conducted, independent, science based speaker testing. I'm hoping that this development will do for speakers what ASR did for DAC's.

Loudspeaker Manufacturers - prepare to have your soiled laundry aired...

 

[Koloth]

I hate to be a stickler but I'm afraid to say that metric you proposed, about the difference between the early reflections curve and the listening window, would likely not be unambiguously preferred...

For example, some research suggests that a speaker with uneven dispersion (and thus, an uneven early reflections curve) will be preferred to a speaker with better off-axis performance if the former has wider dispersion. I've posted this previously on this forum but one of Toole's studies put up three speakers with even (for the time) on axis performance and varying off axis performance.

View attachment 45309

In this example, the Quad ESL clearly has the most even off axis response that is most timbrally similar to the on axis curve. The KEF and Rega both show significant differences. We'd probably call that off-axis performance straight up bad if these were modern speakers.

And yet, the Quad ends up worst in listening tests.

View attachment 45311

We saw something similar with the blind test comparison of the JBL M2 vs Revel Salon2. The Salon won by a considerable margin despite the M2's on axis and off axis performance both being much 'prettier' than the Salons.

Moreover, other research tells us that mixing engineers have a greater preference for narrow directivity designs and/or fewer sidewall reflections while doing their work than do recreational listeners and even mastering engineers, so that's another confounding factor. And individual preferences still exist in this regard.

Also note a timbrally balanced speaker with tall, narrow peaks and dips is likely to perform better than a speaker with a big shallow scoops across various frequencies.

While I'd love to see a universal preference metric as much as everyone, creating one really is a monumental task. Not saying it can't be done though or that we can't get to a useful approximation, just explaining some of the hurdles. With DACs and Amps we have some very clear goals for performance, and we largely know the limits of what's audible. With speakers, we are chasing a moving target.

Id still like to see information like standard deviation from a target curve and such, but we need to have an understanding that diminishing returns and preference have a role to play.

I'm sure Amir's conversation with Sean Olive will be fruitful though.

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.

 

[Blumlein 88]

I hate to be a stickler but I'm afraid to say that metric you proposed, about the difference between the early reflections curve and the listening window, would likely not be unambiguously preferred...

For example, some research suggests that a speaker with uneven dispersion (and thus, an uneven early reflections curve) will be preferred to a speaker with better off-axis performance if the former has wider dispersion. I've posted this previously on this forum but one of Toole's studies put up three speakers with even (for the time) on axis performance and varying off axis performance.

View attachment 45309

In this example, the Quad ESL clearly has the most even off axis response that is most timbrally similar to the on axis curve. The KEF and Rega both show significant differences. We'd probably call that off-axis performance straight up bad if these were modern speakers.

And yet, the Quad ends up worst in listening tests.

View attachment 45311

We saw something similar with the blind test comparison of the JBL M2 vs Revel Salon2. The Salon won by a considerable margin despite the M2's on axis and off axis performance both being much 'prettier' than the Salons.

Moreover, other research tells us that mixing engineers have a greater preference for narrow directivity designs and/or fewer sidewall reflections while doing their work than do recreational listeners and even mastering engineers, so that's another confounding factor. And individual preferences still exist in this regard.

Also note a timbrally balanced speaker with tall, narrow peaks and dips is likely to perform better than a speaker with a big shallow scoops across various frequencies.

While I'd love to see a universal preference metric as much as everyone, creating one really is a monumental task. Not saying it can't be done though or that we can't get to a useful approximation, just explaining some of the hurdles. With DACs and Amps we have some very clear goals for performance, and we largely know the limits of what's audible. With speakers, we are chasing a moving target.

Id still like to see information like standard deviation from a target curve and such, but we need to have an understanding that diminishing returns and preference have a role to play.

I'm sure Amir's conversation with Sean Olive will be fruitful though.

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.

 

[MZKM]

306p also seem to have some weird dip around the crossover frequency:

Spoiler: Digital Stereophony

View attachment 45306

Spoiler: Joe N Tell

View attachment 45307

They only time that dip appears in Amir's measurements is with vertical off0axis, so maybe both of them dip not measure on the reference axis.

 

[Blumlein 88]

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.

I've thought this made sense, but we don't have good data on it do we. I've mostly used ESL's and mostly until recent times had a very long and very narrow room which seemed to suit panels very well.

 

[Jaimo]

I must add that I got started with JBL LSR308's as I needed a reference to compare against while tweaking my Eminent Tech and Magnapan speakers. I ended up dumping my efforts to get better sound out of the panel speakers and I'm totally sold on the JBL LSR family. Anyone looking for a sensible speaker must try out the JBL LSR /M2 line.

 

[Blumlein 88]

I'm quite skeptical of a good sounding speaker from JBL. Congrats on your first review!

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.

 

[JohnBooty]

I hate to be a stickler but I'm afraid to say that metric you proposed, about the difference between the early reflections curve and the listening window, would likely not be unambiguously preferred...

For example, some research suggests that a speaker with uneven dispersion (and thus, an uneven early reflections curve) will be preferred to a speaker with better off-axis performance if the former has wider dispersion.

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

In this example, the Quad ESL clearly has the most even off axis response that is most timbrally similar to the on axis curve. The KEF and Rega both show significant differences. We'd probably call that off-axis performance straight up bad if these were modern speakers.

And yet, the Quad ends up worst in listening tests.

The Quad ESLs are absolutely bizarre. The sound comes out of them like a narrow flashlight beam. In a listening room at Capital Audiofest, I thought that one of the speakers was unplugged. Turns out... no, it was just the guy's head and shoulders in front of me, blocking the sound.

I could see many people not preferring this. Me, I thought they were a blast. I could have listened to those things all. day. long.

Moreover, other research tells us that mixing engineers have a greater preference for narrow directivity designs and/or fewer sidewall reflections while doing their work than do recreational listeners and even mastering engineers, so that's another confounding factor. And individual preferences still exist in this regard.

...we need to have an understanding that diminishing returns and preference have a role to play.

I think two concepts may be getting confounded here? I hope somebody can correct me if I'm wrong. Not even sure if I'm using the correct terminology!

There is definitely room for preference when it comes to dispersion width.

The JBL 305P are narrow ("controlled") directivity speakers. The sweet spot is fairly wide, and you get a very constant response within the sweet spot. Move your head around at your mixing desk, and the sound doesn't change. But outside of this sweet spot, the energy falls off pretty rapidly, which minimizes room interaction.

This creates something like a headphones-like listening experience. It is ideal for production work of course. It is enjoyable for pleasurable listening... as long as that's what you're in the mood for. But it can be somewhat headphone-like and a bit unnatural. Because, after all, in "real life" sounds don't get beamed directly into your eardrums... they interact with the room. So, a wider dispersion can often be more enjoyable.

However, while there's certainly room for preference in dispersion width is there really room for preference when it comes to the timbral quality of off-axis sound? It's hard to imagine that a ragged off-axis response would ever be desirable (unless the magnitude of the off-axis sound was small enough to render it not particularly audible, like the Quad ESLs)

Corrections welcome. After all, the quickest way to get expert opinions is to be wrong on the internet.

They only time that dip appears in Amir's measurements is with vertical off0axis, so maybe both of them dip not measure on the reference axis.

Note - those measurements (with the noticeable 1.5khz dip) are for the 306P. Amir measured the 305P.

 

[Fluffy]

Great review! And the measuring technique appears to be solid. I have one request, if possible – Can you measure distortion at several different SPL, and compare them? I believe SoundStage called this "Deviation from linearity", and it's very useful to know how loud can the loudspeaker be driven acoustically, before it starts to clip and distort.

 

[JohnBooty]

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.

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.

 

[Krunok]

The JBL 305P are narrow ("controlled") directivity speakers. The sweet spot is fairly wide..

Hmm..

 

[amirm]

For ease of reading could lower frequency axis be presented in actual hz/khz values instead of exponents?

I wish I could but have not found a way to do so. It is annoying for sure. I will let klippel know.