Magnepan LRS Speaker Review

[Sancus]

Something is relevant, I'm not sure it has been discovered as of yet.

I'd find this to be a fundamental difference between a panel and a point source, if extrapolating soundfields.

Well we know that the extreme nearfield measurements are going to be very different. The radiating area of a panel is much larger, and there is also a dipole wave. However, the Klippel isn't relying on single measurements like that, it's building a 3D model of all sound emitted by the object.

The questions about the PIR are qualitatively different from the measurement technique. The PIR is, I think(I know there was some back and forth about this and I don't know if the Klippel PIR is slightly different, maybe @MZKM knows) a weighted average of 12% Listening Window, 44% Early Reflections, 44% Sound Power.

So I do think it's possible that this specific calculation needs to be done in a different way for a dipole or that the underlying variables need to be different. But importantly, that doesn't have anything to do with the nearfield measurement technique!

However I also put some weight on Amir's subjective listening test in this case. While I am critical of any individual listening as final arbiters of quality, in this case we are only talking about whether he could hear there was a significant bass deficiency or not. And he said there was.... so... I believe him, because that is hardly a difficult or subtle thing to hear. Thus there are at least some conditions where this speaker will definitely be bass deficient.

Perhaps if you get the right room modes it's OK, but that applies to other speakers as well and is in any case a major flaw.

 

[Vladimir Filevski]

Something is relevant, I'm not sure it has been discovered as of yet.
I'd find this to be a fundamental difference between a panel and a point source, if extrapolating soundfields.

Of course it is discovered - it is covered in books. There is a simple formula for calculating SPL farfield from SPL nearfield measurements and radiating area (cone or panel). It makes no difference if it is a cone ("point source") or a panel. For the same farfield SPL: bigger radiating area = lower nearfield SPL.

 

[MZKM]

Well we know that the extreme nearfield measurements are going to be very different. The radiating area of a panel is much larger, and there is also a dipole wave. However, the Klippel isn't relying on single measurements like that, it's building a 3D model of all sound emitted by the object.

The questions about the PIR are qualitatively different from the measurement technique. The PIR is, I think(I know there was some back and forth about this and I don't know if the Klippel PIR is slightly different, maybe @MZKM knows) a weighted average of 12% Listening Window, 44% Early Reflections, 44% Sound Power.

So I do think it's possible that this specific calculation needs to be done in a different way for a dipole or that the underlying variables need to be different. But importantly, that doesn't have anything to do with the nearfield measurement technique!

However I also put some weight on Amir's subjective listening test in this case. While I am critical of any individual listening as final arbiters of quality, in this case we are only talking about whether he could hear there was a significant bass deficiency or not. And he said there was.... so... I believe him, because that is hardly a difficult or subtle thing to hear. Thus there are at least some conditions where this speaker will definitely be bass deficient.

Perhaps if you get the right room modes it's OK, but that applies to other speakers as well and is in any case a major flaw.

The Klippel PIR curve (which Amir uses) is wrong, as the Early Reflections curve (which Amir also uses) is wrongly calculated (due to poor wording in the standard). The graphs I post are using the correct calculations, the difference is small though.

Here is the Spinorama of the LRS using the the wrong calculation (what Amir posts):

Here is the correct:

 

[amirm]

Guys.... you are killing me... I am beyond maxed out with chores and need to send this speaker back.

But I figured I better string up a bunch of cables and make a quick measurement in room or I will be fielding protests forever. So here it is. It is a single scan, not MMM, as Audio Precision doesn't have an RTA like REW has. Mic is where my nose would be. And the setup is more or less what you saw in the review picture (I had moved the LRS and so tried to place it more or less where it was):

The Revel response is what I had shown before with the dominant room mode at 105 Hz or so.

Interestingly enough, the LRS seems to haver a dip in that area. Seems like there is a cancellation from the back wave. That gets rid of the boominess from that mode but then again, you will have sensation of lack of bass/lightness. That is definitely so combined with the other dip around 42 Hz.

As I note though, overall response is smoother and cleaner than I expected. And also noted, I had to boost the level by 2 dB for LRS to get it to match the Revel more or less.

 

[amirm]

And here it is with a quick and dirty trend line:

 

[Vasr]

Well, the panel area of the LRS is only about 80% larger than the MMG-W. The 1.7i is 3.25x(!) as large as the MMG-W, and I always thought of it as the smallest panel size where they legitimately start to sound decent. Smaller ones I've heard(MMG-W, center channel variants) sounded pretty bad to me. So I still don't think it is that surprising. I don't really believe that Magnepan finally found some magic that lets them make ever-smaller panels work. I think they are just making products to a price point.

This is very misleading again. MMG-W was explicitly promoted by Magnepan for use in conjunction with a sub-woofer so it was never designed to have a meaningful bass extension. It could only be mounted on a wall at an angle not free-standing and so the low frequencies would likely attenuate greatly if not cancel out from the wall reflection in any case to expect it to be full range. The selection of ribbon width (no separate mid/, spacing, the area of the vibrating film, etc., are designed for the intended purpose. This is why I left it out as a meaningful comparison.

LRS is very close to the old MMG and SMG in terms of the actual "voice cone" area. So, the magic if anything would be how they made it much worse than those if the measurements were a true indicator of its response.

 

[BYRTT]

.....The Klippel measurement interpretation here suggests a 300hz roll-off. In-room measurement seems to suggest a 50hz roll-off. This is a fundamental and discordant result between the two that makes a significant difference to the evaluation of the speaker. Before you accept the former as the "truth" for what one can experience in ANY room, you would need to corroborate with actual in-room measurements even if it is not a "perfect" measure for EVERY room.

Until then, it is bad science - an inappropriate use of a measurement/model.

1) Please understand Klippel interpretation or Amir for that sake dont suggest the roll off in room (PIR) you see presented for LRS, that is a spinorama plot standardization called CEA/CTA2034-A, Amir and Klippel analyze the anechoic performance as was DUT out in space away from any reflecting surfaces and present that anechoic data into standardized spinorama presentations.

2) That analyze away from refleting surfaces show about 300Hz roll off yes, but where do you get the data from that users measure in room to be a 50Hz roll off, i cant see any physical objective data for that into this thread other than disapointed owners or users than LRS didn't perform on paper as they had thought it would.

3) You call it bad science and inappropriate use of a measurement/model for that i really cant agree in you cant deny the Klippel anechoic is not the right output and yes in a room makes a difference but then you havent understood Magnespan LRS output in anechoic enviroment have so many flaws it should be a miracle situate that panel in a unique spot in a real room and get state of art performance where flaws as the mess in derectivity and non linear response get repaired relative to anechoic reality, upon your critic so far regarding science it must also be better that a third party as Amir present serious anechoic data for products than before February 2020 where we had nothing other than manufactures data marketing and few amateur or user curves.

4) Someone please study below curves for LRS dipole verse M16 monopole relation to educate read spinorama, should be obvious if one follow directivity index curve and see that whenever there is a relative directivity (more than 0dB on right scale) then PIR or power response curves is lower in output than the direct on axis/listening window signal because it say itself the higher the directivity the less spray into room, should anybody not know it is so that if directivity curve was a flat 0dB curve (true omni) then all the curves on axis/listening window/early reflections/PIR/power response would overlay each other, now study the radars relative to spinorama curves and also how many % LRS fill up inside the glope verse M16 is one thing, another is okay it can be real world verse anechoic for LRS's vertical glope than the dipole canselation when situated on a real floor verse anechois is bit less but i cant imagine its more than a tiny bit because panel is not much wide relative to a 100Hz wave front is 3,43 meters long so whether there is a floor boundary or not to block cancelation interference of huge low end waves they simply cansel in the horizontal plane.

 

[RayDunzl]

Guys.... you are killing me... I am beyond maxed out with chores and need to send this speaker back.

As I note though, overall response is smoother and cleaner than I expected.

Thank you.

 

[richard12511]

Hmm, in room measurements seem to suggest that the Klippel wasn’t far off with its prediction. I’m seeing ~200Hz roll off there. Definitely not a 50Hz roll off, as some are suggesting.

Of course, every room is different.

 

[MRC01]

The difference is quite substantial. We knew that dipoles are hard to measure because near field isn't what you hear, and far-field what you measure is the room as much as the speakers. This reinforces that notion, and shows that numerical approximation has its limitations.
And it also shows @amirm's methodical, transparent approach - thanks for the follow up!

 

[Blumlein 88]

Am I reading this right, the LRS was one foot from back and side wall? Okay with the side wall spacing. However, in an audiophile court with a jury composed of panel owners, you'd be found guilty of negligent operation of a panel speaker with only 1 foot spacing to the rear wall.

Nevertheless, in total the result isn't far from what would be expected. Nice to have the actual measurement however. I'd actually like to see this done for all speakers you review. Over time it provides useful data. Surely you can use REW on a PC and simple measuring mic so you don't need to involve the AP in this measurement.

 

[Vasr]

And here it is with a quick and dirty trend line:

View attachment 85241

Thanks for taking this step. Hope this can be included in all speaker measurements.

This is very different from the predicted Klippel in-room response and what people interpreted based on that and the subjective interpretation. You have to look at it with a filter of room modes especially with a single location measurement. It can be very, very different a few inches away. This is why either a multi-position or RTA sweep (as I had suggested) is necessary for any meaningful room correction. You can do this with REW on a PC with no additional set up necessary. Less than a minute for RTA waving your arms about like a music conductor!

First of all there is no 300hz exaggerated response (this should raise eye-brows about interpreting based on Klippel measurement). Note that some of the interpretation was based on this fall off from 300hz implicitly or explicitly.

The bass extension target is influenced by the deep nulls at 100hz and at 40hz. These are room mode characteristics. If you used this target for REW it would justifiably complain that too much of the area is below the target (primarily because of the below 1khz fit). The target could be quite different if the 100hz null didn't exist.

If I were to equalize this as-is I would pick a +75db flat line for the region below 1khz and ignore any corrections for the nulls or below 60hz. And use a shelf filter to lower the entire tweeter range by about 5db to get a better balance if it could not be achieved by changing the attenuators. The localized nulls would have some effect on clarity and fidelity of lower bass but not necessarily tonal balance.

If I were to evaluate this graph on its own to optimize it, I would say the tweeter range seems to be elevated relative to the low/mid range. This can provide a perception of lower bass content. One can justifiably knock the LRS for this tweeter vs low/mid ribbon balance if it wasn't related to room modes. Or one of the the supplied attenuators might balance it better. With this as is, it would sound too bright and thin.

I would then experiment with both distance from the back wall and the toe-in to affect the null. This is where some of the well-deserved "reputation" for Maggies to be picky about placement comes in. Not that different from a sub with backside porting.

 

[amirm]

Am I reading this right, the LRS was one foot from back and side wall?

No, no. It was 1 foot more than Revel into the room. It is 3 to 4 feet away from either wall. More distance behind it than to the side of it:

 

[richard12511]

And here it is with a quick and dirty trend line:

View attachment 85241

Thanks for doing the in room measurement. I'm seeing ~180Hz rolloff there, so the Klippel was off by a decent amount, but ultimately still much closer than the claimed 50Hz rolloff.

Look how close it measures to the Revel though if you ignore the bass. Pretty impressive, and much better than I would have expected. To me, this review bodes well for larger Maggies (1.7, 3.7, etc.) that can actually give you enough bass to be crossed over to subs. I think these panels may just be too small to give functional bass. They might work really well with a 3 way setup where they can be crossed to midbass modules at 200Hz or so.

 

[amirm]

ou can do this with REW on a PC with no additional set up necessary. Less than a minute for RTA waving your arms about like a music conductor!

That's not the issue. My mic pre-amp is stand-alone and not connected to the PC to use REW with it. Audio Precision is connected of course so I used it.

With respect to bass modes, moving mic is not going to change that due to large wavelength. It will provide smoothing of the response but I provided that in software already.

 

[amirm]

Thanks for taking this step. Hope this can be included in all speaker measurements.

Don't keep your hopes up.

 

[amirm]

Nevertheless, in total the result isn't far from what would be expected. Nice to have the actual measurement however. I'd actually like to see this done for all speakers you review. Over time it provides useful data. Surely you can use REW on a PC and simple measuring mic so you don't need to involve the AP in this measurement.

As I just explained, the AP is easier since it is always connected to my workstation. But yes, I will see if I can modify the setup for the future to run REW.

Usually I run REW using my laptop but lugging that up to the listening room has been a hassle.

 

[RayDunzl]

Dipole panel (over 180Hz) with sealed woofer vs conventional here, adjacent speaker locations, at the listening position, 1/6th smoothing, no EQ

 

[Vasr]

With respect to bass modes, moving mic is not going to change that due to large wavelength. It will provide smoothing of the response but I provided that in software already.

This is where the positioning (if the null is from reflection from the wall) and toe-in comes in. But I have to say that in my current set up, a 120hz dip at the left end of the couch is much, much smaller than the dip at the right end or the middle. Multi-position or RTA won't remove the null but it might average to a smaller dip from localized effects. So the target curve wouldn't over-correct.

 

[amirm]

Dipole (over 180Hz) vs conventional here, at the listening position, 1/6th smooting, no EQ

Can you repost with 50 dB vertical scale? That is the scale that is standardized for speaker measurements which is what I use.