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Magnepan LRS Speaker Review

Francis Vaughan

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Although Amirm uses multiple averaged measurements across the panel dimensio
Important point. No, this isn’t how Klippel works. In fact Klippel is capable of creating exactly what you demand. It solves the PDEs based upon the measurements taken and determined the actual radiating sound wave at each location in space. Of all the measurement systems around it is probably the only one capable of determining what a panel speaker is doing.
Where there is room for more work is in making use of the sound field projections. No doubt, a panel is a different beast and the manner in which it interacts with the room much more complicated than a box speaker.
There is a lot of talking past one another going on here. Everyone knew the first time a panel was measured fur was going to fly. It was a given from the outset that any dipole was not going to fit the standard mould. There is a lot happening here. Linkwitz wrote a considerable amount about this and the nature of how the speakers work in a room. He was no fool. Olive knew Linkwitz and his work, and was always full of praise for his efforts. I think he appreciated that there was much more to learn.
 

Boomzilla

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Precisely the distance I had it from my back wall: 55 inches or 4.6 feet. The manual says this however: " Locate the speakers 2 feet or more in front of a wall." There is no mention of any symmetry requirement. Here is a sample image from Magnepan's own site for 30.7:

IMG_0539.jpg


Not symmetrical at all.
Marketing photos never are. Symmetry is an obvious requirement for any bipolar or dipolar speaker, and a pretty marketing photo does not change that. In fact, shame on you for even trying to muddy the water this way. You know better!
 

Boomzilla

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I'm done.

ASR strikes me as having a bunch of airhead followers of an outspoken guru. To give Amirm fair due, though, measurements and opinions are segregated and opinions are generally qualified. But that (important) distinction is consistently ignored by the average ASR poster, who gloms onto either the measurement or the opinion section and treats it as gospel. And don't try to argue - Amirm said it, I believe it, that settles it - Amen. Of course, the average ASR poster is quick to misunderstand the measurements, to quote Amirm out of context, and/or to put words in Amirm's mouth, but don't confuse the average poster with facts; their minds are made up.

My other objection to ASR is that the quantitive approach is emphasized to the point of worship while the qualitative approach is not only ignored but also denigrated, despised, and ridiculed. Foolishness.

To summarize - I respect Amirm - I respect the ASR website - I consider the measurements a valuable tool - but I consider the average ASR site follower to be a mindless zombie. That said, many ASR followers are far, far better and smarter than what I've described, but they don't seem to post as much. Come to think of it, keeping ones mouth shut in the midst of the madding crowd actually IS a smart thing to do.

Adios
 
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Blumlein 88

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I'm done.

ASR strikes me as having a bunch of airhead followers of an outspoken guru. To give Amirm fair due, though, measurements and opinions are segregated and opinions are generally qualified. But that (important) distinction is consistently ignored by the average ASR poster, who gloms onto either the measurement or the opinion section and treats it as gospel. And don't try to argue - Amirm said it, I believe it, that settles it - Amen. Of course, the average ASR poster is quick to misunderstand the measurements, to quote Amirm out of context, and/or to put words in Amirm's mouth, but don't confuse the average poster with facts; their minds are made up.

My other objection to ASR is that the quantitive approach is emphasized to the point of worship while the qualitative approach is not only ignored but also denigrated, despised, and ridiculed. Foolishness.

To summarize - I respect Amirm - I respect the ASR website - I consider the measurements a valuable tool - but I consider the average ASR site follower to be a mindless zombie. That said, many ASR followers are far, far better and smarter than what I've described, but they don't seem to post as much. Come to think of it, keeping ones mouth shut in the midst of the madding crowd actually IS a smart thing to do.

Adios
Hasta la vista.
 

tuga

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And here is our predicted in-room response:

View attachment 83611

There was no good way to draw the trend line given the large drop in bass response. But I tried anyway.

Speaker Distortion Measurements
At the original point I was measuring the speaker, the highs were very low and as such, I could not get the LRS up to 86 dB let alone 96 dB. Here are what I got anyway:

index.php



Distortion seems to be very much in control at higher frequencies.
index.php



Notice how rough the in-room response is where I measured the speaker.
index.php

Predicted In-Room Response is about perfect from 300Hz upwards. Does it take into consideration this particular speaker's (dipole) topology?
Distortion levels are also commendably low above 300Hz.
Finally actual in-room response sees the speaker making up for the roll-off below 300Hz but the overall response, particularly above 300Hz, becomes less smooth.
Letting aside the fact that the PIR measurement falls flat (highlighting their inneffectiveness with dipoles), could the in-room bump between 300 and 500Hz be the result of room interaction and/or inadequate positioning of either/both listener and speaker?

Interestingly @John Atkinson often comments that panel speakers are difficult to measure at nearfield distances yet the Klippel seems to have had no problems (although a CSD was not shown).

I'd love to see a measurement of a Quad.
 
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tuga

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This speaker is crying for a complementary bass cabinet or open-baffle.
 
OP
amirm

amirm

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Oh, I thought I had post the CSD. Note that I have not tried to optimize its parameters:

Magnepan LRS Ribbon Speaker CSD waterfall Mesaurements.png


This is on the original acoustic axis which has much lower treble energy.
 

tuga

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Oh, I thought I had post the CSD. Note that I have not tried to optimize its parameters:

View attachment 84037

This is on the original acoustic axis which has much lower treble energy.

Thanks.

I don't know how the speaker's built but it looks as though there's a slight delay below 200Hz.
Does it have a bass panel operating up to that frequency?
 

StefaanE

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And therein lies the question - Ideally, a room with symmetrical right and left halves, and one where a minimum of four or five feet of clearance is available from the back wall. But the speakers will ABSOLUTELY sound differently in different rooms (of course, this is true of ALL speakers, but far more so for bipole or dipole radiators).
In other words, these speakers cannot be measured. They have to be bought on faith, and hopefully the room will “play nicely”. If not, it’s not the speakers’ problem, but the room’s. Good to know they’re not for me, because my room is what it is...
 

Willem

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In science, there is always the nagging doubt whether what we are measuring (i.e. the operational definition of a variable) is actually what we want to know. We are pretty convinced that the Klippel system does a good approximation with box speakers, but there are doubts with panels: would all panels show these issues, or just this particular and possibly flawed design? My guess is that a good way forward would be to test what is probably an undisputed high class panel speaker like the modern Quads. The practical snag seems to be that they may be too large to fit the Klippel set up. Alternatively, one could try to measure a Linkwitz design. They are not panels, but at least they are dipoles.
 

bigjacko

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Does the PIR amirm got include the back wave? If the back wave was not included, what would happen if we include it? Can someone simulate it?
 

BDWoody

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This is so funny...pages of measurements which do not mean squat

Ignorance is no laughing matter.
If you learn to understand them, they'll mean more.

This was a blown review, pure and simple.

Because you didn't like the results?
 
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BAMCIS

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The Magnepan world begins with their 3.6 - 3.7 speakers. Not sure who their lesser models are aimed at, especially when speakers like the Tekton Pendragons and JBL Studio 590s cost less and do everything as good or much better- without the hassle and without subs.
 

BYRTT

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Does the PIR amirm got include the back wave? If the back wave was not included, what would happen if we include it? Can someone simulate it?
Yes two planes 360º all around and below edechamps post (thanks) show the formula, not i'm sorry the analyze of this speaker got published, no lets see the truth (thanks Amir) but bit sorry see all the crying that hopes for shoot on standardized CTA2034 spinorama presentation will bring them smoother curves below the hump and/or well it could also look some hope for smooth curve above the hump, but please sleep on these curves of Amir's whenever published for ones loved speaker system and if system sounded good days before Amir published analyze why cant it then sound good tomorrow, or then down the road maybe start correct with some EQ if one cant forget these horror curves published here from time to time, that said honestly even EQ wont change that LRS is a effect box i'm sorry and also confirmed by a ingeneer that is so impressed how genre/contexts sensitive acoustic material make LRS shine skyhigh illusions, 600Hz and up is a mess looking in spinorama plot if someone care to look close and for example compare to the exemplary review of Genelec 8341A..
The mathematics are actually very simple. The reflections curves, as well as PIR, are just averages of the underlying single-angle measurements. For example, the "Side Reflections" curve is an average of the ±40-80° curves. The Early Reflections curve is an average of the various individual reflections curves. And the PIR curve is a weighted average of 12% Listening Window, 44% Early Reflections and 44% Sound Power. The rationale behind this process is detailed in this study.
bigjacko.png
 
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