Magnepan LRS Speaker Review

[yourmando]

So much of this ambiguity/debate could have been avoided by doing a one minute RTA sweep at MLP using REW as a sanity check on the Klippel and near-field measurements and to set the context of what the listening test was actually hearing. To supplement the other measurements.

This. Confirming that the MLP resembles the Estimated In-Room Response would address much of that skepticism that CEA2034 is useful in predicting dipoles in-room.

Either the measurement at the LP or in multiple points in the listening window confirms the PIR, as it usually does, and we debate about other "magic" dipole things that spins can't capture.

Or, the LP measurement doesn't match at all, and we learn something new.

 

[Vasr]

Just a reminder as some seem to be confusing some issues again.

No use arguing with the Klippel results. They are accurately done as if you did them in an anechoic chamber. For monopole, bipole, dipole or broken drive-in theater squawk box they are accurate.

In room measures like REW will have a downward slope because of an artifact of doing measurements that way. If you had the world's perfect speaker with absolute amplifier flat response in an anechoic chamber, and used REW to measure it on axis in the listening room, the result would slope about 3 db/decade or a bit less than 1 db/octave.

In between those you expect due to room gain and possible other factors for the low end below a room's schroeder frequency to be elevated a few db vs the anechoic result.

JA's testing is quasi-anechoic and you have to combine woofer close up measures with the rest and guestimate how to append the low end. There have been a number of knowledgeable people critical of how JA does this. His low ends seem to be too elevated in general over many speakers.

Here is a nice white paper on the topic.
http://audio.claub.net/software/FRD_Blender/White Paper - Accurate In-Room Frequency Response to 10Hz.pdf

BYRTT, MZKM, edechamps, and of course Amir give you these wonderful graphs of how things work that aren't available anywhere else.

Audiophiles are often critical of objectivist audiophiles saying we don't everything there is to know about sound. For most of our gear that isn't a transducer there isn't any mystery. Loudspeakers however is an area where there are still some questions. But don't throw out the great data at our disposal because your sacred ox is gored by results. And remember, I own big panel speakers. So I know how you feel.

I don't disagree with any of this but with all due respect this is missing the forest for the trees.

By casting this as a "for and against" fight about Klippel, the fundamental question about speakers (unlike the fairly transparent electronics) goes unanswered/unexamined/not fully explored.

This is also bad science because one loses perspective on what the whole point of measuring is and gets caught caught up in the minutia of the math and calculations and theory.

Let me make this a very simple question :

If you sat at a typical position in front of a pair of these speakers, is what you hear closer to the REW measurements at that position or is it closer to predicted in-room response from Klippel measurement?

Yes, it is a trick question.

But it needs a clear answer without resorting to technical jargon, juggling multiple variables at the same time and extrapolating to variable parameters that were not used in a measurement. This is not about the accuracy of the Klippel measurement or its ability to measure something as if in an anechoic chamber.

If the goal is to measure the engineering perfection of getting an ideal flat and smooth line and dispersion in an anechoic chamber, let us not confuse that with what you can hear sitting in the typical 6 or 8 feet front of it if you also don't measure it. If you have a model for how that predicts what you can hear at MLP, then make those measurements and show consistency to validate it. Not confuse it with near-field, mid-field, far-field, quasi-anechoic and other tech jargon.

If anechoic measurements provide more insight into things like dispersion and what it means in terms of sweetspots and effects in changes in MLP relative to the speakers which is difficult to measure otherwise, then do that qualitative interpretation separate from tonal balance which is affected by the room and the design of the speaker.

If the goal is to help people understand what they can expect in hearing from a pair of speakers in a typical setting, then make the measurements that directly relate to that with interpretations made reliably from such measurements.

A set of measurements should not lead to more questions than it answers.

The above is not about the LRS. It should hold for any darn speaker one measures. It isn't for or against Amir either.

 

[BYRTT]

Member @thewas_ (thanks) reported this in room MMM PIR for his Kali Audio monitors IN-8 pages back, for that example can it be any better overlay to Amir's PIR curve and also kudos to Amir in his Klippel robot was relative new advanced teritory at that time, kudos to thewas for moving microphone job and feedback the live data of another sample oceans away, and kudos to Harman research and the standardization of CEA/CTA2034 spinorama plots in these stuff give better insight than ever, and yes myself is happy the objective data and as diy had used that to get stunning sound performance in room and also for headphone domain, no problem some lean to subjective side but honestly please let ASR get a few gribs more on stuff (since startup in February about 88 times acoustic review had been published) and more proof for unknown variables probably get revealed down the road, for Magnespan LRS think there is many logics in the normal spinorama plot why its so special good for some and high value, look forward if we can get more users to report real single or MMM as below for PIR curve of LRS and in backwave is directive plus 180º inverted verse frontwave its probably also good to know room dimensions and physical location of panels especial if reported PIR deviate much from standartization in CEA/CTA2034 spinorama plots..

 

[Joppe Peelen]

https://www.audiosciencereview.com/...e-giveaway-for-asr-members.16286/#post-526712

Here is something you'll be interested in. Mario Martinez records in one location with a purist pair of microphones and lays down the tracks with no processing. They've been trying to get best mic position and various other factors right so you can get the closest possible facsimile reproduced when you play it back. Mr. Martinez kindly lets us here on ASR get a free copy of one of his recordings from time to time in exchange for our feedback on it. These are nice recordings with some very good musicians. How can you lose? Go to the thread above and tell him you would like a code to get a free copy.

THanks dude ill surely will take a listen !. im glad some people are playing around with that idea. i myself really love Binaural recordings, or AB. Binaural does not translate as nice into speakers though. but it has a form of quality that sounds rather real. (on headphones almost real real)

completely of topic i must admit but heres a recording i made 8 years ago or something of a trip to the super market (binaural, atmosphere). no processing straight from the recorder. recorder used an Aaton Cantar X1 and some DPA laveliers (i must have looked like some weirdo doing it ). do use headphones if you can. but noticeable is the amount of lows a few of omni directional mics produce

https://1drv.ms/u/s!An2q-4LKABtmgUyvhpEvK5LI1zRv

 

[BYRTT]

THanks dude ill surely will take a listen !. im glad some people are playing around with that idea. i myself really love Binaural recordings, or AB. Binaural does not translate as nice into speakers though. but it has a form of quality that sounds rather real. (on headphones almost real real)

completely of topic i must admit but heres a recording i made 8 years ago or something of a trip to the super market (binaural, atmosphere). no processing straight from the recorder. recorder used an Aaton Cantar X1 and some DPA laveliers (i must have looked like some weirdo doing it ). do use headphones if you can. but noticeable is the amount of lows a few of omni directional mics produce

https://1drv.ms/u/s!An2q-4LKABtmgUyvhpEvK5LI1zRv

:

Thanks recording to Aldi super market its a 22:16 time long track so not finished yet, it was loud and clear at 1:39 you lighted a pipe or cigarette and at 5:09 someone kicked to a container or so to test your microphone capsules dynamic range nice test thanks, got me two free master albums at @Blumlein 88 link (thanks alot), not my favour genre but great recordings and recommended give it a try over there..

 

[Blumlein 88]

Member @thewas_ (thanks) reported this in room MMM PIR for his Kali Audio monitors IN-8 pages back, for that example can it be any better overlay to Amir's PIR curve and also kudos to Amir in his Klippel robot was relative new advanced teritory at that time, kudos to thewas for moving microphone job and feedback the live data of another sample oceans away, and kudos to Harman research and the standardization of CEA/CTA2034 spinorama plots in these stuff give better insight than ever, and yes myself is happy the objective data and as diy had used that to get stunning sound performance in room and also for headphone domain, no problem some lean to subjective side but honestly please let ASR get a few gribs more on stuff (since startup in February about 88 times acoustic review had been published) and more proof for unknown variables probably get revealed down the road, for Magnespan LRS think there is many logics in the normal spinorama plot why its so special good for some and high value, look forward if we can get more users to report real single or MMM as below for PIR curve of LRS and in backwave is directive plus 180º inverted verse frontwave its probably also good to know room dimensions and physical location of panels especial if reported PIR deviate much from standartization in CEA/CTA2034 spinorama plots..
View attachment 85102

Thank you. This shows what there are hints of elsewhere. That the PIR of box speakers is usually pretty good in room with REW type measurements until you hit the schroeder frequency region.

I've been disappointed that with all the smoke and heat in this thread we don't have a half dozen REW MMM's or other in room measures of various LRS installations. That is what is missing from the discussion and is what we need. The low end is often higher in total and usually very uneven.

I'll remind everyone again, the downward slope is an artifact of in room measuring. The speaker is firing a nice flat on axis output just like it would outdoors or in an anechoic chamber. And we apparently hear flat on axis as the most true and uncolored sound. We hear the reference angle even though it measures like the PIR curve.

 

[Blumlein 88]

I don't disagree with any of this but with all due respect this is missing the forest for the trees.

By casting this as a "for and against" fight about Klippel, the fundamental question about speakers (unlike the fairly transparent electronics) goes unanswered/unexamined/not fully explored.

This is also bad science because one loses perspective on what the whole point of measuring is and gets caught caught up in the minutia of the math and calculations and theory.

Let me make this a very simple question :

If you sat at a typical position in front of a pair of these speakers, is what you hear closer to the REW measurements at that position or is it closer to predicted in-room response from Klippel measurement?

Yes, it is a trick question.

But it needs a clear answer without resorting to technical jargon, juggling multiple variables at the same time and extrapolating to variable parameters that were not used in a measurement. This is not about the accuracy of the Klippel measurement or its ability to measure something as if in an anechoic chamber.

If the goal is to measure the engineering perfection of getting an ideal flat and smooth line and dispersion in an anechoic chamber, let us not confuse that with what you can hear sitting in the typical 6 or 8 feet front of it if you also don't measure it. If you have a model for how that predicts what you can hear at MLP, then make those measurements and show consistency to validate it. Not confuse it with near-field, mid-field, far-field, quasi-anechoic and other tech jargon.

If anechoic measurements provide more insight into things like dispersion and what it means in terms of sweetspots and effects in changes in MLP relative to the speakers which is difficult to measure otherwise, then do that qualitative interpretation separate from tonal balance which is affected by the room and the design of the speaker.

If the goal is to help people understand what they can expect in hearing from a pair of speakers in a typical setting, then make the measurements that directly relate to that with interpretations made reliably from such measurements.

A set of measurements should not lead to more questions than it answers.

The above is not about the LRS. It should hold for any darn speaker one measures. It isn't for or against Amir either.

A speaker in room is radiating the sound it does in an anechoic chamber. On axis is what we hear most. So we hear the anechoic curve above schroeder regions, and it measures as a downward slope. It doesn't sound like a downward slope to us. It sounds clear and flat because it is. Our brain combined with our hearing has ways of mostly hearing past the room except at the low end. Our microphones and measuring software can't do that so you get the artifact of a downward slope. PIR is taking this into account largely and predicts what we measure in room, but what we hear is actually the on axis anechoic response. The lower few hundred hertz are a different situation. We'll hear something much like it measures, but it will almost always be more uneven and elevated vs anechoic measures.

So in essence there is no measurement that matches what we hear the way you are asking of it to do. We know enough to piece it together pretty well. A truly flat responding speaker we'll hear as flat if it doesn't act up off axis to corrupt what we hear in a room.

So the measurement that tells us what we'll hear listening to speakers in a typical setting is the Klippel measurements down to 500 hz or a bit lower depending upon room size. That lower end part is very important, but the in room version of it is something of a kludge, an add on. You probably should rely on in room measures for the low end. But there is no universal room.

 

[Juhazi]

Sad that we don't have more in-room spot measurement of LRS. This debate has been going on for a week now...

I believe that NFS's PIR is misleading because of dipole bass. I believe that Stereophile/Atkinson's measured room response is pretty universal, just like his other ones like LS50.

 

[Frank Dernie]

for me this holds true until you get pronounced room modes , the massive uplift in a certain bass frequency can be really distracting IME .

Very true, but being an old bloke I have plenty of experience of positioning speakers such that they don't do that. Once one has achieved that the gain from room compensation software is, IME, modest.

 

[tuga]

No use arguing with the Klippel results. They are accurately done as if you did them in an anechoic chamber. For monopole, bipole, dipole or broken drive-in theater squawk box they are accurate.

The Klippel measures (ultra-)nearfield, unlike anechoic.
Panels have a very large radiating surface.
There's a slight chance (ultra-)nearfield might not the best way to go at it...

This was @John Atkinson on measuring the ESL-2912:

It's always difficult to assess the acoustic behavior of a large panel speaker like the ESL-989.
First, the nearfield measurement of the low frequencies will not show the effect of the dipole cancellation, as the antiphase backwave increasingly wraps around to cancel the speaker's direct output with decreasing frequency.
The peaked-up bass shown in fig.2 will therefore tend to be more flat in the farfield than it appears in this graph. In addition, when measuring a loudspeaker, it is assumed that the microphone is in the speaker's farfield; ie, several times the largest dimension of the diaphragm.
With the largest dimension of the ESL-2912 being its panel height of 54" and my routine distance from the microphone being 50", this assumption is no longer true.
As a result, due to the proximity effect, there will be a slight downward trend with frequency in the measured response, as fig.2 also shows.

Fig.2 Quad ESL-2912, anechoic response on center-panel axis at 50",
averaged across 30° horizontal window and corrected for microphone response,
with nearfield response of woofer plotted below 300Hz.

https://www.stereophile.com/content/quad-esl-2912-loudspeaker-measurements

 

[Newman]

How is that a relevant criticism of a total sound field measurement?

 

[Vladimir Filevski]

Magnepan LRS, anechoic response on mid-panel tweeter axis at 50",
averaged across 30° horizontal window and corrected for microphone response,
with the nearfield panel response plotted below 300Hz. (source)

If you chop 6dB off the 75Hz region (an artifact caused by the nearfiled measurement) the response becomes a lot flatter below 350Hz and down to perhaps 60Hz.
Having seen hundreds of JA's measurements I am inclined to believe that his is a much more accurate illustration of reality than the Klippel's.
In other words, Klippel don't do dipoles well (enough).

Several times it was pointed that nearfield measurements (as JA's in Stereophile) for dipole loudspeakers must include 6 dB/octave negative slope. So, with starting point of 300 Hz we must "chop" 6 dB of the 150 Hz region (one octave lower) and 12 dB of the 75 Hz region - not only 6 dB!
I measured over one hundred different loudspeakers (believe it or not!) with farfield/nearfield merging at about 250 Hz. Comparing those with (only) several measured in-room responses (including one monstrous open-baffle dipole) I am confident that there is no such room magic that can turn (anechoically) bass-shy speaker in to a neutral-sounding one. Both for monopole or dipole loudspeakers, room standing modes can indeed boost some frequencies, but also can introduce very deep holes, so there is no free lunch.
Any nearfield measurements, mine or JA's, are inherently less accurate than Klippel's NFS.

 

[tuga]

Several times it was pointed that nearfield measurements (as JA's in Stereophile) for dipole loudspeakers must include 6 dB/octave negative slope. So, with starting point of 300 Hz we must "chop" 6 dB of the 150 Hz region (one octave lower) and 12 dB of the 75 Hz region - not only 6 dB!
I measured over one hundred different loudspeakers (believe it or not!) with farfield/nearfield merging at about 250 Hz. Comparing those with (only) several measured in-room responses (including one monstrous open-baffle dipole) I am confident that there is no such room magic that can turn (anechoically) bass-shy speaker in to a neutral-sounding one. Both for monopole or dipole loudspeakers, room standing modes can indeed boost some frequencies, but also can introduce very deep holes, so there is no free lunch.
Any nearfield measurements, mine or JA's, are inherently less accurate than Klippel's NFS.

I don't doubt that "nearfield measurements, yours or JA's, are inherently less accurate than Klippel's NFS".
That is not my point. Rather that measuring nearfield is a problem with dipoles.

Regarding @John Atkinson 's nearfield below 300Hz, can you explain the rationale behind your idea of "chopping" "12dB off the 75Hz region" instead of 6dB?

 

[tuga]

How is that a relevant criticism of a total sound field measurement?

It is a criticism of how we interpret a total sound field measurement of a dipole speaker. Because it is a dipole speaker.
I am happy to be proven wrong but let us wait for other dipoles to be measured, particularly panel speakers...

 

[Sancus]

The Klippel measures (ultra-)nearfield, unlike anechoic.
Panels have a very large radiating surface.
There's a slight chance (ultra-)nearfield might not the best way to go at it...

The Klippel's measurement distance is irrelevant though because the mathematics involved allow it to extrapolate those initial measurements to any distance. It doesn't matter what the source of the sound is or how it generates that sound.

The only cases we've seen where it got it wrong was because something was systematically affecting the initial measurements AND all subsequent measurement, like reflections off the microphone cage/apparatus(high frequency ripple) or temperature of the woofer(KH80). No one has shown any indication that the extrapolated measurements are ever wrong except for when the Klippel itself calculates an error margin due to soundfield complexity, which is a known factor. In fact, we know that the Klippel checks its extrapolation against additional measurements so it's most likely correct about that error margin.

The most likely criticism, in my view, was the PIR calculation was off for a dipole but given the evidence in other posts I'm inclined to believe that maybe it's fine. Regardless from my perspective the only real way to move forward for those insisting that something is wrong with the measurements would be to acquire some REW measurements of the LRS in various places and see whether they actually do have more bass than the PIR calculation is expecting them to have. But honestly, I suspect they won't.

As an owner I honestly don't see how a panel the size of the LRS could possibly produce sufficient bass when some of the significantly larger Magnepans are already somewhat disappointing in that area, until you get up to the 3.7 or 20.7 at least. Basically I don't think these results are nearly as surprising as so many people think.

But I also don't think this review is terrible for Magnepans in general. The biggest issue here is one that is likely alleviated by the larger panels. So it definitely isn't fair to say that these measurements would represent anything other than the $650 speaker they are based on.

 

[Vladimir Filevski]

Regarding @John Atkinson 's nearfield below 300Hz, can you explain the rationale behind your idea of "chopping" "12dB off the 75Hz region" instead of 6dB?

Simple - if it is flat at 300 Hz, one octave below at 150Hz it must be -6 dB, and one octave below 150 Hz it is 75 Hz with another -6 dB, for a total of -12 dB at 75 Hz.

 

[Vladimir Filevski]

I don't doubt that "nearfield measurements, yours or JA's, are inherently less accurate than Klippel's NFS".
That is not my point. Rather that measuring nearfield is a problem with dipoles.

There is no problem, if you are knowing inherent limitations (or virtues) of the measurement technique. It is known exactly what is going with nearfield measurements with a mic within quarter of inch from the loudspeaker membrane, and also is known exactly what is going with the Klippel's NFS "nearfield" mesurements.

 

[tuga]

The most likely criticism, in my view, was the PIR calculation was off for a dipole

This is what I am referring to.

 

[tuga]

There is no problem, if you are knowing inherent limitations (or virtues) of the measurement technique. It is known exactly what is going with nearfield measurements with a mic within quarter of inch from the loudspeaker membrane, and also is known exactly what is going with the Klippel's NFS "nearfield" mesurements.

Dipoles radiate differently and measurements reflect this.
Care must be taken when comparing them with measurements conventional monopole box speakers.

 

[Sancus]

This is what I am referring to.

Well OK, but if the PIR calculation is off it's nothing to do with how the measurements were taken. As far as I understand, the PIR is a weighted average of listening window, early reflections and sound power. Its calculation doesn't even involve any of the specialized Klippel math.

If someone thinks the PIR is wrong they're going to need to collect some inconsistent measurements(the JA one doesn't seem inconsistent to me, and I frankly trust the mess Stereophile makes of measurement below 300hz much, much less than the Klippel anyways.) and potentially show the correct weights for a dipole if they differ for whatever reason.