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Magnepan LRS Speaker Review

tuga

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A quick re-reading of Toole's Sound Reproduction 3rd edition, 7.4.2. notes an interesting experiment. Toole tested a Rega Model 3, and Kef 105.2 box speakers, and a Quad ESL 63 in a blind, robotic switched test environment. The results specifically showed that the Quad ESL, when listened to in mono, received markedly low marks for sound and spacial quality, but received marks close to the others when listened to in stereo. Toole closed by suggesting that evaluating in mono is important because it lets you "find out what you really have" and that stereo listening should be left for demonstration and impressing everybody. It is a curious position, given this is an artificial use case.

He also noted that the Quad fared poorly on pop music that contained significant hard panned components in the mix, and fared well on classical and jazz recordings that intrinsically contained real spatial content.

This study was done in 1985. He didn't have the advantage of technology like the Klippel to measure the speakers, so some of the analysis is a bit handwavy. It would be most interesting to measure an ESL 63, and maybe a 105.2 Given we have Toole's experiment results, there may be some useful insights to be gained.
It is indeed a curious position if we take into account that no one listens to music using a single speaker.
Could it be a case of misinterpreting the data?

There's a chance that "the Quad fared poorly on pop music that contained significant hard panned components in the mix" because of its narrow horizontal dispersion.
 
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It is indeed a curious position if we take into account that no one listens to music using a single speaker.
Could it be a case of misinterpreting the data?

There's a chance that "the Quad fared poorly on pop music that contained significant hard panned components in the mix" because of its narrow horizontal dispersion.

yeah even there esl63 did not had great dispersion... still sounded rather nice though :)
 

Blumlein 88

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Interesting, when I had Quad ESL-63s I came upon almost the complete set of the early mono Mercury Living Presence LPs. They sounded pretty good, and the discs were in pristine condition. I eventually played them using only one Quad. They sounded so much more right that way I always listened to them with one speaker only. With two speakers in mono there was too much faux space. Even in mono the early Mercury recordings were of good quality and gave a good rendition of the large space in which they were recorded. Covering that up with a dollop of extra spaciousness diminished how good those recordings were.
 

Wes

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I'd say that a dipole is better and worse than a cone/box speaker...

Speakers are flawed in numerous ways, unlike say electronics - or at least to a much greater degree than electronics. You have to pick the best sounding, or least bad sounding, mix of things in a multi-variate factor space.

It may be that only large panels can compete with cone/box speakers in that mix - I dunno as I've never heard a panel this small.
 

NTK

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any idea what kind of differences one might expect between the 2 ?
The "basis/fitting functions" given by the solution to the underlying PDE (partial differential equation), the Helmholtz equation, in the spherical coordinate system is efficient for modeling loudspeakers that have low aspect ratios (close to the shape of a cube). It is less efficient for panel shaped objects or thin and slander objects. What that implies is we need a lot of measurement points.

It is analogous to decomposing a square wave into a Fourier series. We need a lot of terms to accurately approximate the square wave with sines and cosines, because sines and cosines are not efficient in approximating squares.

The analysis performed by the Klippel NFS includes evaluating the fitting errors, which Amir has shown in this review. The radiation patterns of loudspeakers are much more complex at the higher frequencies, and can be seen by the higher fitting errors. It is less of a problem for the lower frequencies.
 
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The "basis/fitting functions" given by the solution to the underlying PDE (partial differential equation), the Helmholtz equation, in the spherical coordinate system is efficient for modeling loudspeakers that have low aspect ratios (close to the shape of a cube). It is less efficient for panel shaped objects or thin and slander objects. What that implies is we need a lot of measurement points.

It is analogous to decomposing a square wave into a Fourier series. We need a lot of terms to accurately approximate the square wave with sines and cosines, because sines and cosines are not efficient in approximating squares.

The analysis performed by the Klippel NFS includes evaluating the fitting errors, which Amir has shown in this review. The radiation patterns of loudspeakers are much more complex at the higher frequencies, and can be seen by the higher fitting errors. It is less of a problem for the lower frequencies.
i can imagine. since the driver does not look as tall at low frequencies, as well as low end wont add or substract as much compared to higher frequencies with small delays due to distance. like measuring a line source slightly off axis vertically creating dips and peaks. expecially if the line is not so long. at the lower end not much changed :) well he did mention he took allot of points, more then usual. so who knows :)
 
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BYRTT

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Predicted in room response for Amir's spinorama analyze of LRS had been critized alot with reference to stereophile curve and Amir's own distortion graph, think often its hard to interpreet various ratios of plots scales to each other and therefor made them overlaid to same scales and corrected for their nearfield positioned microphones that cant see baffle dimensions is not infinite size when microphone sits so close, correction i used was thanks to member Joppe Peelen when he published curves of his own panel in room at 12,5cm and 100cm where i used their difference as the correction curve.

Index_spinorama.png


Left one is LRS stereophile nearfield curve overlaid to spinorama and right one is filtered as told at beginning..
PIR_examples_1a.png


Left one is LRS distortion nearfield curve of Amir overlaid to spinorama and right one is filtered as told at beginning..
PIR_examples_1b.png


Other PIR curve of a smaller panel size is left one that is Joppe Peelen's own creation at 100cm without any filtering and tweeter passband, right one is the predecessor Magnespan MMG measured in room at 100cm by Dick Olsher..
PIR_examples_1c.png


Think above tell we should be happy enough Amir own this anechoic wonder machine and share some more precise analyzes we can use to educate and reference/calibrate our own real world methods of acoustic benchmarks, had a hard try look for more PIR measurement into this thread because some postulate that over and over users PIR measurement show Amir's analyze is off for panels, but honestly the other Magnespan PIR measurement into this thread is really not for Magnespan LRS but other models so please forget that comparison as argument in those other panel are not same dimensions and technology.

Should there be some low end to hope for made below simulation of one floor boundary close to a line source using a Jeff Bagby spreadsheet and avarage of those 10 positions of a woofer piston to get a boundary correction filter, in the avarage grey curve..
Boundary_avarage_of_6inch_to_42inch_from_floor_200mS.gif


Above filter added to spinorama of Magnespan LRS based Amir's spindata..
PIR_examples_1x1x_500mS.gif



In quote below we have one member that ordered a set of LRS and we could hope for he would share a PIR curve down the road ..:)..
Went ahead and ordered a pair, though it seems it might be awhile(4-8 weeks) before I can hear them.
 
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RayDunzl

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I've lost the plot...

What is PIR?
 
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I think the question is not so much if a dipole is better or worse then a a conventional speaker... what i think and i speak for myself and i guess some others, is people wonder how come the thing measure so badly, while allot of people still enjoy them.
A better question might be: "how bad does a speaker need to measure for people to not enjoy it?"

And honestly, the LRS measurements don't look like they are that bad.
 
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Predicted in room response for Amir's spinorama analyze of LRS had been critized alot with reference to stereophile curve and Amir's own distortion graph, think often its hard to interpreet various ratios of plots scales to each other and therefor made them overlaid to same scales and corrected for their nearfield positioned microphones that cant see baffle dimensions is not infinite size when microphone sits so close, correction i used was thanks to member Joppe Peelen when he published curves of his own panel in room at 12,5cm and 100cm where i used their difference as the correction curve.

View attachment 84483

Left one is LRS stereophile nearfield curve overlaid to spinorama and right one is filtered as told at beginning..
View attachment 84480

Left one is LRS distortion nearfield curve of Amir overlaid to spinorama and right one is filtered as told at beginning..
View attachment 84481

Other PIR curve of a smaller panel size is left one that is Joppe Peelen's own creation at 100cm without any filtering and tweeter passband, right one is the predecessor Magnespan MMG measured in room at 100cm by Dick Olsher..
View attachment 84482

Think above tell we should be happy enough Amir own this anechoic wonder machine and share some more precise analyzes we can use to educate and reference/calibrate our own real world methods of acoustic benchmarks, had a hard try look for more PIR measurement into this thread because some postulate that over and over users PIR measurement show Amir's analyze is off for panels, but honestly the other Magnespan PIR measurement into this thread is really not for Magnespan LRS but other models so please forget that comparison as argument in those other panel are not same dimensions and technology.

Should there be some low end to hope for made below simulation of one floor boundary close to a line source using a Jeff Bagby spreadsheet and avarage of those 10 positions of a woofer piston to get a boundary correction filter, in the avarage grey curve..
View attachment 84497

Above filter added to spinorama of Magnespan LRS based Amir's spindata..
View attachment 84498


In quote below we have one member that ordered a set of LRS and we could hope for he would share a PIR curve down the road ..:)..
VERY VERY NICE

im glad the fast measurement could be of any use. (although they dont look very nice :) ah well it was in my room , not a particular big one either )

I like the floorbounce graph to (nice you made a combination of the 10 positions), i had in my system a low pass around 400 hz when i first made the speakers, lowering the hump afterwards.
still a dynamic 8 inch driver in a cabinet can out perform most of the smaller panels when it comes to low end for sure. (and they should ofcourse , not being OB)


[EDIT]

i found some old measurements (2 years old) of my panels outside without filter (maybe a tiny bit cleaner result? , not gated 1/12 smoothing used , SPL not calibrated) (it does uses wires here instead of the current foil type conductors) but they look pretty similar to the one you used in the overlays , except that weird suckout and the 94 hz peak, are not present in the garden.

measured at 2 meters distance in a garden.

1600902136304.png
And here compensated it with a low pass , creating an acoustical crossover much higher. and getting rid of the peak these all tend to have, or at least make it less dramatic
1600902165295.png

and here with the old tweeter , im at v8 or something by now. (forgot what that weird peak was at the top end)
1600902234868.png

same speaker (maybe with some minor crossover differences) in room @ 1.5meter, ofcourse no gating could be used :(
1600902345429.png
and the suck out is back once more :)

i also measured a SMGA at this same instance i measured the in room measurement above.
Green is a magnepan SMGA and blue was my contraption back then. measured @ 1.5 meter. ofcourse no gating could be used :(
1600903124489.png

not sure if you can do anything with them in the findings you posted above. i forgot i had these. i still got the REW files if you by any change need.
 
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Francis Vaughan

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It is indeed a curious position if we take into account that no one listens to music using a single speaker.
Could it be a case of misinterpreting the data?
I don't think there is any misinterpretation of the data. The basic premise seems to be that listening in stereo masks problems, not that listening in mono prevents a speaker performing to its potential. There is no clear justification for this, but there is an underlying idea that the ESL 63 was always a poor design in comparison with the others, with objectively poorer response. So the conclusion was that the speaker could never sound as good, and thus when it did, it must be because listening in stereo masked the problems.
IMHO, whilst this might be the correct reasoning, I don't think this one experiment is nearly enough to justify it. It assumes too much of what is being proved. I can't find any other experiments with the ESL 63, or indeed any other dipoles by Toole.
I haven't looked yet, but I want to sheet home the experimental background to the protocol of mono listening to speakers now used. I would hope that there is further work that compares only conventional speakers that demonstrates stereo listening masking issues in the speakers.
 

williamwally

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I'm genuinely curious if listening to the LRS in a smaller room will subjectively 'bring the bass back' as many here are saying it will.
 

Thomas savage

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No, I am not playing with semantics at all. Not in the least. Nor am I "stuck", nor did I "erroneously" say something referring to math instead of to the use of formulae, or whatever it is exactly that you mean there. You clearly have made the assumption that your understanding of this stuff is perfect and that I am just being silly. I implore you to be less hasty with your assumptions and conclusions.

One of the fundamental difficulties with dialogs of this nature, concerning philosophy-science, is that most people simply don't have any appreciation for the degree of linguistic precision that is needed with dialogs of this nature, in order for them to be truly meaningful. It is necessary to abide a high degree of linguistic precision, such that ambiguity is fully avoided. The importance of this cannot be overstated.

You have provided a clarification of what you (or maybe someone else, it doesn't matter) meant by "actual". This was good. You assert (strongly in bold) that people colloquially use "actual" synonymous with "direct" as distinct from "indirect". Okay, but it matters nought whether this is or isn't a colloquial practice.

To make clearer what is meant by "actually" in this context, you now talk about "indirect measurements" vs. "direct measurements". I am expected to know precisely how you define the two, such that I would know with absolutely certainty which measurements you would deem "direct" and which measurements you would deem "indirect". I am afraid that I fall short of this expectation. I think I might have a fuzzy idea what you might mean by this, but we would both be fools were we to permit this dialog to go further without first making entirely certain that what you mean is entirely clear to both of us. It is absolutely essential for you to state the necessary and sufficient conditions by which some particular measurement would be deemed an "actual" measurement.

Once you have made it entirely clear what the distinction is, between a direct measurement and an indirect measurement, the next step is to inquire into whether the measurement of torque taken on some class of dynamometer meets the necessary and sufficient conditions such that it would be deemed a "direct" measurement. You are most likely thinking at this point that the distinction between a direct and an indirect measurement is self-evident and that it is silly for me to ask you to define this distinction. But as soon as you start to think about this question seriously, you will mostly likely change your mind. Or at least I hope that you will.

I want to suggest a few questions that you may find relevant, as you ponder the question of how to define the distinction between direct and indirect measurements. How exactly is the measure of torque obtained? Does it involve taking a measure of force and multiplying it by a predetermined distance? If so, how is the measure of force obtained? Does it involve a strain gauge? If so, is force inferred from a reading of voltage? If so, is the voltage measured by way of comparison to calibrated voltage sources and using calibrated resistors? What is involved in the calibration of the calibrated voltage sources? Are they calibrated by way of comparison with other voltage sources, or how exactly?

If you want the easy way out, all you need to say is something along the lines of, "A direct measurement is a measurement that is directly taken."
Regardless of linguistic precision this communication medium is a compromised one.

I'd keep that in mind and maybe walk away from certain situations here when things start to be less enjoyable and it's obvious no common ground is being forged or even basic mutual understanding and respect .

That's advice for everyone, I'm just quoting this post as its a fair example of the fact .
 
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Here's a view of the 1.7i in my living room. As you can see, they are quite large - standing at 65" tall, with a few more inches added to that height by using the Mye stands.

View attachment 84072
Yep, that is what prevents me from getting Maggies. I was thinking of the LRS, but I heard them at a store compared to Vandersteen 2s and they seemed anemic and metallic compared to those. I remember my 1.6QR sounding better, but then again I would always use them with a subwoofer.
 

Blumlein 88

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I wonder what side by side LRS with tweeter in the middle would sound like? Should extend the bass an octave. Might even study the directional patterns and find an angle that might smooth the lobing while reducing the head in the vice effect.
 
OP
amirm

amirm

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Doesn't Magnepan have a 30 day trial period? Listen to them; if Amir is right you won't like them and you can send them back.
Good luck with packing and sending this massive speaker back. :)
 

Newman

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.... I'm not even trying to defend the LRS or shit on your review; I've never heard it, don't want one, and will continue to fund your experimentation through patreon. You could very well be totally right: it has no bass and sounds wonky in exactly the way it's measured! But we've got only one panel speaker put to the test. Why am I being mocked for the entirely reasonable curiosity if this is an appropriate methodology for panel speakers - considering they are, after all, a totally esoteric, oddballish and rarer speaker design?
Main point to absorb is that Klippel builds a model of the total sound field in anechoic space. And it does it for any sound source, without caveat, whether point or line or pretzel or acoustic laser beam. So, yes, it is appropriate for this (or any) speaker.

Some reading, link, includes some discussion of line-source speaker from post #31.
 
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