Magnepan LRS Speaker Review

[ruinevil]

1 has a Frequency of 412 Hz, a gain of -7.8 and a Q of 1.44.

 

[Vasr]

It is not odd if you look at it in reverse in how I eq the speaker:

There is peaking in the output from 250 Hz to about 900 kHz. Take that out and the bass response is would then be in-line with the rest of the response (more or less for this speaker). This is why I applied this eq:

See how I pulled down that peaking? Once there, the problem is lack of output which I compensated by shifting all other frequencies higher. Once there, the response was far superior. So no question that the peaking is the problem.

Now that fix doesn't do a lot for the lower bass drop so it still lacks dynamics.

Sorry, I am not sure I understand exactly what you are really saying here.

Are you saying the peaking is a characteristic of the speaker (and not some room mode)? If so, then I think almost everybody has misunderstood what a bass roll-off here actually means (as in bass-deficient).

If that peak is an exaggerated speaker FR (independent of any room modes), then that is quite different from saying it is bass-deficient.

Just as a thought-experiment, imagine if that peak (or elevated low mid) was caused by a room mode. It would still show the same "fall" on either side (but it wouldn't make the speaker bass-deficient).

What you have done would be the wrong way to EQ it. A target would be somewhere below 80db running relatively flat through to about 800hz. It would lower the volume overall (like it was a more inefficient speaker). And then it would have downward slope through the treble. That wouldn't be considered as a bass-deficient speaker by any means. At worst an inefficient one.

What you have done is to measure the FR, take the highest point and pull everything together to be in the middle and claim it is rolling off steeply on either side. This is the weirdest interpretation of a FR response I have seen anywhere.

To me, it looks like the speaker has a fairly good and flat response down to about 50hz with an exaggerated low-mid (which can certainly be faulted if not due to a room mode and may be that is an intentional signature if not an engineering mistake) and it is only relative to that it seems as if it is bass-deficient (and treble deficient on the other side). I don't think anybody understood it that way and are thinking that it has an exaggerated bass roll-off.

May be you didn't intend it to mean that way but this is a really bad interpretation of the measurements.

 

[amirm]

If the initial photo was representative of the test conditions, the "tests" are worthless.

You need to read the reviews and understand them before commenting. The test conditions have nothing to do with the picture. That setup is for listening only. And are perfectly fine for a speaker to be located.

Speakers are measured using a robotic, $100,000 measurement system that scans the speaker in 3-d space and produces full response of the speaker in all directions as if there was no room.

Why are measurements so poor for a design that has been celebrated for decades as one of the best sounding speakers in the world? The apparent answer would seem to be that the speakers are fine - the measurements are wrong.

No, the "apparent answer" is that people are not critical listeners and don't know how to properly evaluate a speaker. They fall in love with a "flat" speaker and spacious imaging (whether in the music they bought or not) and buy them.

If the LRS measurements are so misleading, what veracity should be placed on all the OTHER measurements of the "Audio Science Review" website?

This specific review on purpose was written for experienced readers of this forum, not newbies just joining us. Normally I would be including this preface in the review to eliminate the misunderstandings you have:

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Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.

I used over XXX measurement point which was enough to compute the sound field of the speaker within 1% error.

Temperature was 77 degrees. Measurement location is at sea level so you compute the pressure.

Measurements are compliant with latest speaker research into what can predict the speaker preference and is standardized in CEA/CTA-2034 ANSI specifications. Likewise listening tests are performed per research that shows mono listening is much more revealing of differences between speakers than stereo or multichannel.

Spinorama Audio Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker is and how it can be used in a room. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:

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So stay back, learn the topic and technology/research behind this review and then comment. We could do without the shooting from the hip....

 

[amirm]

Are you saying the peaking is a characteristic of the speaker (and not some room mode)?

What room modes? The spinorama measurements are always anechoic with zero room effects.

The peaking is above modal region anyway so the speaker produces it and is in control.

 

[archerious]

They don't.

Never make the mistake of listening with your eyes! And remember that the LRS is a much smaller/less expensive speaker than the 1.7i.

That's a great point!

 

[Vuki]

Looking at Klippel predicted in-room response and amirm's measured one (even, if I understood it right -of a lsr elevated 5ft of the floor?), I think no one can say Klippel did a good job with this speaker.

 

[thanhh]

I've been using Magnepan MG12/QR which is not much bigger than the LRS, but my in room measurement doesn't look as bad as Amirm. Below is REW measurement with 1/24 smoothing of the Maggies and my Kef Q950 side by side (no EQ).

I crossover both speakers at 80Hz and run them with REL T5i. After Dirac, I've got very similar Frequency response from both speakers but still prefer the Maggies for most of my listening. I tried ABX blind test but pick out the Maggies everytime due to they sound bigger (sounstage) than the Kef. Not sure what is wrong with the LRS though, I thought they should mearsure better or at least very close to my very old Maggies

 

[amirm]

What you have done would be the wrong way to EQ it.

No. The effect is the same whether you increase the response on the two sides of the peak, or grab the peak and pull it down. Computing the inversion for the peak is much easier than to compute the two other filters.

 

[Blumlein 88]

Dipole vs conventional:

Here's a MartinLogan dipole vs JBL LSR 308, adjacent to each other in my room.

This is a "no EQ" sweep for both types, left and right speakers playing, 1/48 smoothing, within the range of the dipole, at the listening position.

View attachment 83850

Bass not shown since it isn't dipole - sealed 12" - so not pertinent at this time.

I'm sorry I don't have an LRS to flog for you.

Which color is which? Black is more uneven.

 

[amirm]

Looking at Klippel predicted in-room response and amirm's measured one (even, if I understood it right -of a lsr elevated 5ft of the floor?)

That's because as I explained in the review, the frequency response changes radically with height. You basically can get any mid to high frequencies you want depending on where you put the microphone or your ear. The in-room response was also at the first acoustic center than the second one. So they don't match in that regard.

 

[Vasr]

What room modes? The spinorama measurements are always anechoic with zero room effects.

The peaking is above modal region anyway so the speaker produces it and is in control.

I was just clarifying that it isn't just to be sure.

No. The effect is the same whether you increase the response on the two sides of the peak, or grab the peak and pull it down. Computing the inversion for the peak is much easier than to compute the two other filters.

The theoretical effect is the same. But...
Actually, in Room EQ, you don't want to boost anything if you can help it because of power requirements. If you run any of the standard room correction tools on that curve if it measured that way, they wouldn't do what you did but do what I mentioned as the target above. Doing that EQ as I have suggested wouldn't cause any issue with dynamics, it would just be lower in overall volume. With most of the exaggerated mid chopped off in an aggressive system like Dirac, so there would be no tonal balance issues.

But that isn't the point. It is a referential frame issue.

It is whether you look at the response as a fairly flat response from 50hz-800hz with an exaggerated low-mid or do you look at it as a normal low-mid with FR falling off on either side. The latter is what people have interpreted as the speaker being bass-deficient which is a wholly wrong idea of how this speaker behaves in the bass region. No 6db/octave or any roll off till about 50hz. That is pretty good for a panel of this size.

It is that exaggerated low-mid that is the problem to be fixed/addressed but only after verifying if the response in a room situation doesn't flatten it out for other reasons in the way a speaker of this type works. That is beyond my area of expertise.

I don't want to belabor this point anymore because I am repeating myself. I hope people understand what I have said and explain better whether it is really bass-deficient as people have understood or that it just shows an exaggerated low-mid in an anechoic chamber measurement.

 

[Vuki]

That's because as I explained in the review, the frequency response changes radically with height. You basically can get any mid to high frequencies you want depending on where you put the microphone or your ear. The in-room response was also at the first acoustic center than the second one. So they don't match in that regard.

Alright, but in PIR the balance is completely wrong

 

[RayDunzl]

Which color is which? Black is more uneven.

Black = JBL LSR 308

 

[Vuki]

I mean - you're doing all this complicated measurements on this ultra expensive Klippel machine to be able to objectively "see" the louspeaker's audio performace and from there predict it's performance in real room (disregarding modes of course). But in this case I see it as complete flop.
"Simple" quasianechoic measurement would much closer predict real room behavior of this loudspeaker.

 

[stevenswall]

Now I regret paying $2390 with tax for my 1.7i. The Kef R3 cost less and probably sound better.

And also across a much, much larger area vertically and horizontally.

 

[amirm]

I mean - you're doing all this complicated measurements on this ultra expensive Klippel machine to be able to objectively "see" the louspeaker's audio performace and from there predict it's performance in real room (disregarding modes of course). But in this case I see it as complete flop.
"Simple" quasianechoic measurement would much closer predict real room behavior of this loudspeaker.

No. Quasianechoic measurements produce incorrect results in bass. The speaker appears to have an infinite baffle.

If you mean in-room measurements, a single microphone at one point cannot show you the total response of the speaker. Only 3-D spherical measurements can properly describe the soundfield of the speaker.

Tell me how you would find out the directivity of the speaker like this:

We have true insight into this speaker which you would not remotely have without it. You also have confirmation of the results based on my listening tests.

 

[stevenswall]

Going above and beyond . Results line up with most reviews when reading between the lines. I suspect a lot of the problems emanate from the mid and tweeter sharing the same membrane. Issues kinda shared by coax dynamic drivers.

What issues? The drivers are separate in a coax, and there aren't audible diffraction issues with Genelec MDC drivers. No inherent flaws as far as I know of with coaxial drivers. I'd be interested to learn if there are though.

 

[Vuki]

No. Quasianechoic measurements produce incorrect results in bass. The speaker appears to have an infinite baffle.

If you mean in-room measurements, a single microphone at one point cannot show you the total response of the speaker. Only 3-D spherical measurements can properly describe the soundfield of the speaker.

Tell me how you would find out the directivity of the speaker like this:

We have true insight into this speaker which you would not remotely have without it. You also have confirmation of the results based on my listening tests.

No offence, but I find your listening tests as biased as anyone else's.

 

[Blumlein 88]

A few Jonathan Valin quotes from the TAS review of the LRS.

All by themselves, the LRS are, indeed, quite lean in the lower mids, power range, and bottom octaves.

To hear what makes the LRSes special, you have to move up a few octaves into the heart of the midrange.

It will need considerable power and careful placement to perform at its best—and frankly it will also need a decent subwoofer if you want full-spectrum fidelity.

And yes there is plenty of irony in me quoting TAS review comments here.

Maybe they'll let Amir write some reviews for them.

 

[amirm]

No offence, but I find your listening tests as biased as anyone else's.

We have been through this many times. Your opinion of my listening tests has no foundation because my testing methodology doesn't match others. It follows research protocols which others do not (training, mono listening, etc.). You can dismiss them but don't give me that reason as it doesn't hold water.