Magnepan LRS Speaker Review

[Wes]

I'm glad you did not say "it will be more than a 30.7" !

 

[LarryRS]

josh 358 said: "Good question about the woofers. There will be a variety of form factors to fit different usage cases. I'm not sure how you'd put a dipole woofer in a corner without losing its dipoleness and the advantages of dipole bass. You could put it on a sidewall near a corner. The woofer is designed to be highly concealable, by the way, since the DSP will let you adjust timing, meaning that it doesn't have to be right by the panels."

By using the DSP with my ML Dynamo 1100x's to integrate them into the room, and then tuning level, crossover and phase with the 3.7i's that is what I hoped to achieve. I ended up with the crossover set at 35Hz, very low, so the subwoofers are not localizable and are more easily identified by what's missing when they're turned off than what's added when they're operating. Be that as it may, my hope is that Magnepan's latest work might eventually result in the development of dipole dynamic bass units that can be added to existing Magneplanars. Who better to develop a dynamic woofer system for Magneplanar panels than Magnepan?

 

[josh358]

josh 358 said: "Good question about the woofers. There will be a variety of form factors to fit different usage cases. I'm not sure how you'd put a dipole woofer in a corner without losing its dipoleness and the advantages of dipole bass. You could put it on a sidewall near a corner. The woofer is designed to be highly concealable, by the way, since the DSP will let you adjust timing, meaning that it doesn't have to be right by the panels."

By using the DSP with my ML Dynamo 1100x's to integrate them into the room, and then tuning level, crossover and phase with the 3.7i's that is what I hoped to achieve. I ended up with the crossover set at 35Hz, very low, so the subwoofers are not localizable and are more easily identified by what's missing when they're turned off than what's added when they're operating. Be that as it may, my hope is that Magnepan's latest work might eventually result in the development of dipole dynamic bass units that can be added to existing Magneplanars. Who better to develop a dynamic woofer system for Magneplanar panels than Magnepan?

I think there's a pretty good chance that it will. Not the current 30.7 C woofers, they wouldn't be appropriate for that application, but I expect we'll see some larger dipole subs that will work with the existing panels as well. There are interesting challenges, but that's what makes it fun!

 

[richard12511]

In all fairness, they aren't usually this open! They decided to show the lab prototypes of the 30.7 C because it was a radical departure for them, and they wanted feedback from customers, dealers, and the press before committing to it. Sonically, it will be the same, but they're only now putting the finishing touches on the CAD and beginning the production engineering, so no one, including Magnepan, has seen the cosmetics yet, except in some very cool looking renders.

Do you know if they intend to have a "C" version for every model?

 

[josh358]

Do you know if they intend to have a "C" version for every model?

There will certainly be "C" models down the line, but as far as I know, discussion hasn't proceeded to that point.

 

[William53b]

This is a review and detailed measurements of the Magnepan LRS (Little Ribbon Speaker). It was kindly sent to me by a member and costs US $650.

NOTE: as you will see later, this is a special review with far more detail than I usually show in a speaker test. I thought it would be "fun" to see much more extensive treatment of these speakers. Result was three full days of measuring, processing, processing again and again, generating slides, generating those again, and again. I hope you appreciate the extra work that has gone into this review and no, I won't be doing this with future reviews.

Given the detail level, this is not for a casual reader of these reviews. As such, feel free to skip to subjective listening results and conclusions.

I was thankful for the thin and relative light weight of the LRS when I went to measure it and carry it to my listening room:

View attachment 83600

As you can sort of tell from above picture, there are two panels side-by-side. One to the left with wider size and traces and the other handling higher frequencies with much narrower width. Per feedback from membership, I selected the measurement axis/point as being more or less where the "X" mark is in red (center of the panel). Alas, I had to empirically move this [position (in software) as you will see later. I wanted the center of that axis to be on the tweeter but the auxiliary stand that I built was symmetrical and wouldn't allow me to go close to the right.

You see an indentation toward top. This is not normally visible but the reason for it is a large button screw that holds the panel down (I think).

A set of metal stands forces a some amount of lean back which I find surprising. By dropping a couple of rings, you can tilt the speaker less and is something that is recommended by the company if listening past 10 feet or so. I was worried about measuring the speaker so leaning back in its default position so I tiled it up mostly to the angle that would be if you used the secondary, more upright position.

I was fortunate enough to get a preview measurement that was performed by Klippel distributor in US, Warkwyn labs which was published in AudioExpress magazine. My measurements match theirs although the results as presented are different due to some improvements I made as you see later.

Warkwyn measurements showed that the Klippel system was struggling to characterize the sound field despite using over 2000 measurement points. I was going to use more measurement points only to realize it would take 5 hours just to do the 2000 point measurement! It was really strange to watch the system make a vertical set of measurements and move a millimeter and do that all over again! The tall speaker meant there was a lot of time lost moving up and down, lengthening measurements.

Not only was the measurement time long, but so was processing the 1.5 Gigabyte file to compute the sound field and various measurements. Computational time was in the order of half hour.

Klippel NFS Measurement Accuracy
As most of you hopefully know, the Klippel NFS makes a series of near-field measurements (in order to benefit from better signal to noise ratio) and then using those points, solves the partial differential equations that describe the wave propagation. Once there, we are able to predict the sound field in any point in space in the far field (where we more or less listen). The technique while wonderful, has limitations in that if the sound field becomes too complex, it requires many more measurement points and "orders of expansion." Despite using high measurement points used per above (more than 2X of any speaker I have measured), the sound field was too complex in high frequencies to get accurate readings. Klippel is able to determine the error by making additional "real" measurements that it then compares to what it has computed. The difference is expressed in dB of error. Usually the results are below -20 dB indicating 1% error in most or all of the audible band. That was not the case here:


View attachment 83601

In theory, this should NOT have happened. Lay intuition about this speaker is that they are two vertical drivers each sending out a perfect plane wave of their own. Reality is different in that there are clearly other sources of sound interfering with each other, creating a highly complex wave front. Fortunately, the error is not high enough to distort what we are interested in. Here is a Klippel graph showing the actual versus computed response at a certain point:

View attachment 83602

Focusing on the right, the actual measured response was in red but the blue is what is computed. As you see, as the frequencies go higher, error increases but fortunately it still more or less follows the response of the speaker which is dropping like a rock above 10 kHz or so.

Speaker Radiation Pattern
Normally I lead with our spinorama measurements but here, I thought we work backward and first look at the directivity of the speaker. Here it is in the horizontal axis. That is, you are facing the speaker and the graph shows what happens 360 degrees around the speaker:

View attachment 83603

Being a dipole speaker, the LRS radiates what you see in the front, in the back. The back response however is split into two halves (top and bottom of the graph) so not as intuitive. But hopefully you see it now with the annotations in place. We have a nice constant beam width up to low treble and then the pretty picture corrupts:

View attachment 83604

The notch around 1 kHz in directivity is due to offset nature of the tweeter panel. I have the "right" speaker so the treble has baffle amplification on the left but not right. At least this is what I assumed when I created the slide but I am not sure the tweeter is active there. Open to ideas from readers.

The most interesting part and what cost me a lot of time and effort was the vertical dispersion:

View attachment 83606

Yes, as you go above 1 kHz or though, the speaker starts to beam hugely, creating a super narrow angle of +- 10 degrees where you get the full response. Go up or down below this and you have massive loss of high frequencies. Indeed that is what I had when I first measured the speaker as did the Warkwyn plots. So I started to adjust the reference axis higher and higher until I got it in that sweet spot.

Spinorama Speaker Measurements
Here is our standard graph now:

View attachment 83608

To give you an idea of the response was before I changed it, here it is:

View attachment 83609

You basically get no highs or low!

Both graphs show odd modulations of on-axis response above 3 kHz as indicated by the jagged peaks. And the fact that this speaker doesn't generate much sound until you get to 300 Hz or so.

One of the "benefits" of a line source of this type is that you get little radiation above and below the speaker. We can see some of that effect in the early window and the levels of the floor and ceiling reflections:

View attachment 83610

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.

Sound Field Visualizations
Let's get fancy and look at how the sound propagates from the LRS first in horizontal plane. I can only show this at one frequency at a time so let's start with 500 Hz or so that is squarely in the domain of the main low frequency panel:

View attachment 83613

View attachment 83614

The color shows sound pressure level (red the highest, blue the lowest). We see a wave front radiating from the driver.

Now let's step up to 2.2 kHz:

View attachment 83615

If my interpretation is correct, we now have both drivers radiating and creating interference patterns.

Going to 10 kHz isolates just the tweeter:

View attachment 83616

The tweeter panel is the right but we also get images on the left side of the speaker.

I also analyzed a vertical slice but this time, I will just show a static picture (above animations were a lot of work to create):

View attachment 83620


View attachment 83617


Imagine you are standing on the right looking into the speaker. We see that the radiation pattern on the back and front follow the tilt axis of the speaker as it was measured. Also indicated clearly is that we have a narrow range of radiation before we hit pockets that are nulls or have less power (no red color in them). These interference patterns must be due to multiple sources playing at once and creating the complex sound field I talked about at the start of the review.

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:

View attachment 83618

Distortion seems to be very much in control at higher frequencies.
View attachment 83619

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

Impedance Measurements
Electrically panel speakers like LRS are simple resistive loads:

View attachment 83621

Impedance dips down to 3 ohm so you better have an amplifier with good current capability. The phase though is nearly zero. The vertical scale is only 20 degrees and hence the visually large variation.

Transition to Far Field
Klippel computers the response of the speaker and can show at what point we are approaching far field of the speaker. For LRS and at frequencies of 400 Hz and higher, that is 3 meters or 10 feet. So better not sit too close to them:

View attachment 83622

Subjective Speaker Listening Tests
I first positioned the panel right at me and started to play. What I heard sounded like it was coming from a deep well! I then dropped the little rings on the stand and repositioned the speaker as you see in the picture (less toed in). That made a big difference and for a few clips I enjoyed decent sound. Then I played something with bass and it was as if the speaker was drowned under water again. It wasn't just absence of deep bass but rather, quietness on top of that.

Even when the speaker sounded "good" you would hear these spatial and level shifts that was really strange. As the singers voice changed tonality, it would sometimes shift left and right. And change in level no doubt due to uneven frequency response. There was also some strange extended tail to some high frequency notes that would seem to go on forever.

Just when I thought I had the speaker dialed in, I leaned back some and the tonality got destroyed. You had to sit in the proverbial vice around your head to get the "right" sound out of LRS.

I applied a quick and dirty inverse fix to the response to get some semblance of neutrality:

View attachment 83623

The one PEQ shown, combined with an overall lift of the entire response made a huge difference. Speaker was no longer dull, lacking both bass and treble. Alas, after listening some, the highs got to me so I put in the right filter to fix that. And while the LRS could handle the boost in low frequencies well, bringing for the first time some tactile feedback, it did start to bottom out so I had to put that sharp filter for extreme lows.

Once there, I was kind of happy until I played the soundtrack you see at the bottom. Man did it sound horrid. Bland and some of the worse bass I have heard.

When it did sound good -- which was on typical show audiophile tracks -- the experience was good. Alas, every track would sound similar with the same height and spatial effects.

Conclusions
The Magnepan LRS is a hugely flawed speaker with moments of delight. If I could control what you listen to, e.g. in an audio show or dealer room, I could convince you it is much better speaker than it is. The best way I can explain this is that the designers solved 30% of the physics of building a speaker, and threw you in there to solve the rest! You take on the job of spending what must be a lifetime messing with location, tilt, EQ, etc. to get sound that is good for more than a few select tracks.

I am confident a better job can be done than what we see in LRS. Maybe making the panels smaller causes the beaming and interference patterns worse. I don't know. What I do know that this is not a product finished and fit for use by a consumer.

I wonder how much simulation and in field analysis was performed as I have shown here. Doesn't seem like much was done to find and remove issues with this speaker.

Needless to say, I can't recommend the Magnepan LRS.

------------
As always, questions, comments, recommendations, etc. are welcome.

Have to go and see if I can fix our dishwasher now. Too cheap to pay someone $500 or more to fix this German invention. If you want me to consider hiring someone to fix it, please donate generously using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

 

[William53b]

Thanks so much for the in depth review.

Not completely surprised with the results and your conclusions because I own the 1.7i's, and it's been a nightmare redesigning the XO with quality components, and once I had the sock all the way off, saw all kinds of things wrong with the panel design from a mechanical engineering standpoint, so am fixing those first, before wasting any more time on the XO.

If you think the LRS measurements are not up to snuff, You should see what three drivers on an undivided panel can do to your tests.

You are a kind an generous person to donate so much IP to the public, as it is obvious to me that you could fix most of what you test and find wrong, and easily open the worlds best modding shop.

Regards-

 

[YSC]

Thanks so much for the in depth review.

Not completely surprised with the results and your conclusions because I own the 1.7i's, and it's been a nightmare redesigning the XO with quality components, and once I had the sock all the way off, saw all kinds of things wrong with the panel design from a mechanical engineering standpoint, so am fixing those first, before wasting any more time on the XO.

If you think the LRS measurements are not up to snuff, You should see what three drivers on an undivided panel can do to your tests.

You are a kind an generous person to donate so much IP to the public, as it is obvious to me that you could fix most of what you test and find wrong, and easily open the worlds best modding shop.

Regards-

Hi there, as I am really curious and a absolute layman, can you shred some light on what's so wrong? and that any sort of in room measurements you've done after fixing them ?

 

[ctbarker32]

There isn't terribly much that isn't already known, since the lab prototype went on a brief road show so that they could get feedback on it. But for anyone who missed that, it's a "wife friendly" Maggie with panels that are only 12" wide and a couple of concealable dipole woofers that use multiple dynamic drivers to make the system full range without compromising quality or creating that old bugaboo, audible discontinuity between the dynamic woofers and planar panels. The woofers themselves are self powered and use DSP for dipole equalization and room tuning.

Otherwise, it's been christened the 30.7 C (that's what we're calling it, anyway), the cosmetic renders look amazing, and it involves a lot of innovations for Magnepan beyond the use of dynamic drivers and DSP. Many of these will make their way down market as newer models are released, including a new aluminum frame design. Right now, they're tuning that up so that the extrusion die can be made, and as always, that's an iterative process -- for example, yesterday we were trying to figure out how to position the ribbon tweeter on the beveled extrusion without causing diffraction issues or bringing it out of time with the midrange, or having to make two extrusion dies. And the day before that, it was a question of how to align the T-nuts in the channel of the extrusion for assembly, and in that case, it was an engineer at the extrusion company who came up with a simple and elegant solution.

Big on the list of things to do, and the most fun -- continue developing new configuration options for the concealable woofers. Since we haven't been able to get the laws of physics repealed, we've been kicking around a lot of innovative approaches, and I mean a lot.

Assuming this all goes without a hitch and the first DSP unit is delivered as expected, Wendell Diller will take the first pair on a tour so that everyone has a chance to hear it.

As an owner of the LRS, I have worked pretty hard to integrate the panel with a fast subwoofer such as the REL T5. I was able to have very good success by adding a simple outboard high-pass filter inline from the amp to the LRS that really improved things. Since anyone who is serioius about getting the most out of your speakers, I wonder why you don't simply add an option for such a high-pass filter directly into all your models? I can't see how this would be a high cost addition. I was able to do it externally for about $15 per speaeker. You already have facilities for adding resistors to tailor the tweeter. Why not give some attention to the low end? High quality musical subwoofers are abundently available. You seem to already be moving in this direction. I know you cannot keep up with demand but an LRS-X model with my suggested high-pass feature would be very well received in the market.

 

[josh358]

Thanks so much for the in depth review.

Not completely surprised with the results and your conclusions because I own the 1.7i's, and it's been a nightmare redesigning the XO with quality components, and once I had the sock all the way off, saw all kinds of things wrong with the panel design from a mechanical engineering standpoint, so am fixing those first, before wasting any more time on the XO.

If you think the LRS measurements are not up to snuff, You should see what three drivers on an undivided panel can do to your tests.

You are a kind an generous person to donate so much IP to the public, as it is obvious to me that you could fix most of what you test and find wrong, and easily open the worlds best modding shop.

Regards-

Why do people buy a budget model and then complain that it's a budget model? Magnepan makes speakers with multiple drivers, true ribbon drivers, and with dual magnet assemblies in which the drivers are a good deal more rigid than the single-magnet drivers. They cost more because the components cost more.

Sure, they could use esoteric components, but they'd lose their reputation for high bang-for-the-buck. There are planars out there that are no-holds-barred -- neodynium magnets and what have you -- but you'll be spending in the tens of thousands for them with, frankly, little gain in performance.
Magnepan's tradition is value engineering -- the components they use are chosen because blind listening tests show that they are better for the price. For example, Mark Winey, the company's president, told me that he didn't OK the addition of the supertweeter to the 1.7 -- its predecessor, the 1.6, didn't have one -- until it was preferred in blind listening tests by both expert and non-expert listening panels.

Pretty much everything that goes into the speakers is blind tested and often customers don't grasp this. They do uneconomical things at home (where labor is free and it really doesn't matter) and don't understand why Magnepan doesn't use them. That's why you won't see the likes of esoteric wire -- in blind testing, no one was able to hear it. Ditto (since we're talking crossovers) air core chokes -- they used to use them and then compared them blind with iron core chokes and nobody could hear a difference. (You can bet they would have if the test hadn't been blind, lol.)

Before you redesign the crossover, by the way, be sure you know what they've done -- people frequently mess this up. The crossover from the tweeter to the supertweeter is a 1.5-way crossover, which is to say that the whole tweeter plays up to a certain frequency and then a narrower segment takes over at the very top. This optimizes both power handling and dispersion in a panel of limited size. Also note that the frequency response is designed to decline gradually with frequency rather than being flat -- a standard house curve. So many don't understand the purpose of a house curve and think speakers should be flat, ouch. Also, that in an average room you should use the 1 ohm series resistor -- it is equivalent to the center position on a tweeter pot.

At least one commercial mod gets these things wrong. Just imitate the values with better caps and you'll be fine. Or use a higher order XO between the woofer and tweeter, although you'll probably be losing as much as you gain -- it really depends on how loud you like to listen. Retain the series XO so the impedance drop from the tweeter to the supertweeter doesn't throw off the XO point, and to damp the panels out of band -- that's a lot more important in a planar than it is in a dynamic.

If you increase the strength/mass/damping of the baffle, or improve the mounting of the driver in the baffle -- all good things -- make sure you don't cause diffraction issues. Hell, you might be able to reduce diffraction with half round end pieces and some felt -- I don't know, haven't tried.

Not all of the design considerations at all, but an indication of the thought and experience that have gone into these speakers. Forgive me if you're already familiar with some or all of this -- some DIYers are truly knowledgeable -- but from what I've seen, most people know a lot less about commercial planar design than they think they do.

 

[YSC]

I had a friend who owned a tube amp driven 1.7i, TBH that sounds very good to my ears, but since it can go with pretty high volume and the owner listens to female vocals and 60s pop which don't have a lot of bass, it maybe the bass deficiency don't sound annoying

 

[DHT 845]

Tube amp and ribbon / planar magnetic is very good match if tube amp is not strained too much. Cutting off low end with active crossover or passive inline is adviseable. I used to do it with large bohlender ribbon (actually push-pull planar magnetic driver).

 

[617]

Why do people buy a budget model and then complain that it's a budget model? Magnepan makes speakers with multiple drivers, true ribbon drivers, and with dual magnet assemblies in which the drivers are a good deal more rigid than the single-magnet drivers. They cost more because the components cost more.

Sure, they could use esoteric components, but they'd lose their reputation for high bang-for-the-buck. There are planars out there that are no-holds-barred -- neodynium magnets and what have you -- but you'll be spending in the tens of thousands for them with, frankly, little gain in performance.
Magnepan's tradition is value engineering -- the components they use are chosen because blind listening tests show that they are better for the price. For example, Mark Winey, the company's president, told me that he didn't OK the addition of the supertweeter to the 1.7 -- its predecessor, the 1.6, didn't have one -- until it was preferred in blind listening tests by both expert and non-expert listening panels.

Pretty much everything that goes into the speakers is blind tested and often customers don't grasp this. They do uneconomical things at home (where labor is free and it really doesn't matter) and don't understand why Magnepan doesn't use them. That's why you won't see the likes of esoteric wire -- in blind testing, no one was able to hear it. Ditto (since we're talking crossovers) air core chokes -- they used to use them and then compared them blind with iron core chokes and nobody could hear a difference. (You can bet they would have if the test hadn't been blind, lol.)

Before you redesign the crossover, by the way, be sure you know what they've done -- people frequently mess this up. The crossover from the tweeter to the supertweeter is a 1.5-way crossover, which is to say that the whole tweeter plays up to a certain frequency and then a narrower segment takes over at the very top. This optimizes both power handling and dispersion in a panel of limited size. Also note that the frequency response is designed to decline gradually with frequency rather than being flat -- a standard house curve. So many don't understand the purpose of a house curve and think speakers should be flat, ouch. Also, that in an average room you should use the 1 ohm series resistor -- it is equivalent to the center position on a tweeter pot.

At least one commercial mod gets these things wrong. Just imitate the values with better caps and you'll be fine. Or use a higher order XO between the woofer and tweeter, although you'll probably be losing as much as you gain -- it really depends on how loud you like to listen. Retain the series XO so the impedance drop from the tweeter to the supertweeter doesn't throw off the XO point, and to damp the panels out of band -- that's a lot more important in a planar than it is in a dynamic.

If you increase the strength/mass/damping of the baffle, or improve the mounting of the driver in the baffle -- all good things -- make sure you don't cause diffraction issues. Hell, you might be able to reduce diffraction with half round end pieces and some felt -- I don't know, haven't tried.

Not all of the design considerations at all, but an indication of the thought and experience that have gone into these speakers. Forgive me if you're already familiar with some or all of this -- some DIYers are truly knowledgeable -- but from what I've seen, most people know a lot less about commercial planar design than they think they do.

I assume you kept the original crossovers intact somewhere?

 

[William53b]

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

Oh my word. I have both, and don't play them side by side. The R3 will just humiliate them, of course the R3 isn’t dipole, but that can be somewhat fixed by using a rear firing tweeter that in most cases in my quest for a better sounding speaker, really helps the humble box.

Hi there, as I am really curious and a absolute layman, can you shred some light on what's so wrong? and that any sort of in room measurements you've done after fixing them ?

As a layperson, no, not really. Suffice to say that they are asking a membrane of polymer under tension to do something that it cannot, in this configuration, and there are many thing wrong with the panel itself. That's why Magnepan's have a separate tweeter in their better models.

Almost all rooms are six sided boxes with holes in them, and there are two ways for a music lover or someone who is more interested in the equipment to make them accommodating: You can try and duplicate a sound or mastering studio with things manufactured to modify that box. I don’t want to live and relax in a studio, so instead of just spending money, I invest in collectible rugs and fiber arts, quality bookcases with books of various sizes suitable for display, medium to heavy duty lined drapes on all windows and finally, a heavy fabric cover for my TV for when I'm listening. Also fabric folding frames of tryptics work well behind speakers and as bass killers in corners.

This makes my wife love our living room, regardless of my stereo.

For imaging, start with each speaker 3’ out from the back wall and at least six feet apart and keep listening and repositioning them to taste. Once you have a width figured out, you can experiment with the depth. Both speakers prefer being near an outside wall, so their ability to reproduce sound is fairly dependent on you selecting the right model in their lines for the room size. Also, Maggie’s may well like to be further from the back wall than three feet, depending on your room size. (Corrected.)

I have a 12x14 room for my not in regular use equipment and my living room is 12x24, and we are going to make that both wider and taller.
All rooms properly set up work better on the long axis. Both speaker manufacturers products produce better bass when using an outer wall for bass coupling.

 

[William53b]

Why do people buy a budget model and then complain that it's a budget model? Magnepan makes speakers with multiple drivers, true ribbon drivers, and with dual magnet assemblies in which the drivers are a good deal more rigid than the single-magnet drivers. They cost more because the components cost more.

Sure, they could use esoteric components, but they'd lose their reputation for high bang-for-the-buck. There are planars out there that are no-holds-barred -- neodynium magnets and what have you -- but you'll be spending in the tens of thousands for them with, frankly, little gain in performance.
Magnepan's tradition is value engineering -- the components they use are chosen because blind listening tests show that they are better for the price. For example, Mark Winey, the company's president, told me that he didn't OK the addition of the supertweeter to the 1.7 -- its predecessor, the 1.6, didn't have one -- until it was preferred in blind listening tests by both expert and non-expert listening panels.

Pretty much everything that goes into the speakers is blind tested and often customers don't grasp this. They do uneconomical things at home (where labor is free and it really doesn't matter) and don't understand why Magnepan doesn't use them. That's why you won't see the likes of esoteric wire -- in blind testing, no one was able to hear it. Ditto (since we're talking crossovers) air core chokes -- they used to use them and then compared them blind with iron core chokes and nobody could hear a difference. (You can bet they would have if the test hadn't been blind, lol.)

Before you redesign the crossover, by the way, be sure you know what they've done -- people frequently mess this up. The crossover from the tweeter to the supertweeter is a 1.5-way crossover, which is to say that the whole tweeter plays up to a certain frequency and then a narrower segment takes over at the very top. This optimizes both power handling and dispersion in a panel of limited size. Also note that the frequency response is designed to decline gradually with frequency rather than being flat -- a standard house curve. So many don't understand the purpose of a house curve and think speakers should be flat, ouch. Also, that in an average room you should use the 1 ohm series resistor -- it is equivalent to the center position on a tweeter pot.

At least one commercial mod gets these things wrong. Just imitate the values with better caps and you'll be fine. Or use a higher order XO between the woofer and tweeter, although you'll probably be losing as much as you gain -- it really depends on how loud you like to listen. Retain the series XO so the impedance drop from the tweeter to the supertweeter doesn't throw off the XO point, and to damp the panels out of band -- that's a lot more important in a planar than it is in a dynamic.

If you increase the strength/mass/damping of the baffle, or improve the mounting of the driver in the baffle -- all good things -- make sure you don't cause diffraction issues. Hell, you might be able to reduce diffraction with half round end pieces and some felt -- I don't know, haven't tried.

Not all of the design considerations at all, but an indication of the thought and experience that have gone into these speakers. Forgive me if you're already familiar with some or all of this -- some DIYers are truly knowledgeable -- but from what I've seen, most people know a lot less about commercial planar design than they think they do.

I'll assume you started this out with a rhetorical question. Thanks for the info, all good to know.

 

[wje]

As an owner of the LRS, I have worked pretty hard to integrate the panel with a fast subwoofer such as the REL T5. I was able to have very good success by adding a simple outboard high-pass filter inline from the amp to the LRS that really improved things. Since anyone who is serioius about getting the most out of your speakers, I wonder why you don't simply add an option for such a high-pass filter directly into all your models? I can't see how this would be a high cost addition. I was able to do it externally for about $15 per speaeker. You already have facilities for adding resistors to tailor the tweeter. Why not give some attention to the low end? High quality musical subwoofers are abundently available. You seem to already be moving in this direction. I know you cannot keep up with demand but an LRS-X model with my suggested high-pass feature would be very well received in the market.

Good points that you've made. I did watch the video on Y.T. where you utilized the $15 Parts Express high-pass crossovers in your setup. I took a slightly different approach. I have a pair of RSL Speedwoofers in my setup with my LRS speakers. I utilize the MiniDSP DDRC-24 in between my pre-amp and amplifier. The MiniDSP allows me to set all of the crossover levels, the slope (e.g. 24dB in my case for a faster response). Also, I've utilize Dirac Live! with the MiniDSP to apply appropriate room corrections. All in all, I'm pretty happy. In the past 10 years, I've owned 20+ pair of speakers, and 10+ in my current room/home over the past 5 years. I've had speakers that have cost 8x the price of the LRS, but there were issues here and there that had me switching to other options. Had the MiniDSP DDRC-24 and Dirac Live! been available 5 years ago, I'm sure I could have cut that number of purchases down greatly. I've tried to listen to 80s rock on the LRS, which I've found to be not so pleasant. However, since I listen to jazz and smooth jazz 90%+ of the time, I don't have issues.

Next step. Building proper supports for the LRS and getting rid of the factory stands. I'll be using very strong "L" shelf brackets, 3/4" Poplar and floor spikes for a total cost of about $80.00.

 

[DonH56]

My experience with Maggies over the years is that successful subwoofer integration depends greatly upon the room and its treatment, natch. By and large a high-order crossover (18 dB/oct min, 24 dB/oct preferred) makes integration better/easier as the panel's bass interferes less with the subwoofer (and vice-versa). My first design (ca. 1979-1980) used a 12 dB/octave crossover but was almost immediately replaced by an 18 dB/oct version, a fairly high order at that time. It was quickly obvious that 12 dB/oct was not steep enough. I later moved to a conventional Linkwitz-Riley design with 24 dB/oct slopes and was able to integrate a sub pretty cleanly (at least to my measurement mic and ears). I have almost always treated the wall behind to reduce comb filter effects and such but that does not help the deep bass much (wavelengths too long, and the panel transitions to more of a big point source instead of a line source).

Integration is much easier these days with DSP (e.g. I incorporated an analog all-pass filter in my crossover to help time-align sub and panels) but it is not necessarily "easy".

FWIWFM - Don

 

[josh358]

As a layperson, no, not really. Suffice to say that they are asking a membrane of polymer under tension to do something that it cannot, in this configuration, and there are many thing wrong with the panel itself. That's why Magnepan's have a separate tweeter in their better models.

The dynamics of a tensioned polymer membrane are well understood and have been used to good effect in electrostatics and planar magnetic speakers for over 50 years now, including speakers which are/were considered among the best of the time. They have their own set of advantages and tradeoffs vis a vis dynamic drivers. I have a friend who is still using KLH-9's that were manufactured in what, 1964? And there are people who use Quads that were made in 1959. Those old stats still have a clarity that even most megabucks dynamics don't.

The woofer panels are actually pretty amazing -- they'll go out to 8kHz or so. Putting a tweeter strip down the side is a compromise, of course, but in practice, it works pretty well and has great bang for the buck. Of course, they won't match the true ribbon driver, which is widely considered one of the best tweeters ever made, but again, it comes down to cost -- an inexpensive speaker is never going to match an expensive one, whatever kind of speaker it is!

 

[William53b]

The dynamics of a tensioned polymer membrane are well understood and have been used to good effect in electrostatics and planar magnetic speakers for over 50 years now, including speakers which are/were considered among the best of the time. They have their own set of advantages and tradeoffs vis a vis dynamic drivers. I have a friend who is still using KLH-9's that were manufactured in what, 1964? And there are people who use Quads that were made in 1959. Those old stats still have a clarity that even most megabucks dynamics don't.

The woofer panels are actually pretty amazing -- they'll go out to 8kHz or so. Putting a tweeter strip down the side is a compromise, of course, but in practice, it works pretty well and has great bang for the buck. Of course, they won't match the true ribbon driver, which is widely considered one of the best tweeters ever made, but again, it comes down to cost -- an inexpensive speaker is never going to match an expensive one, whatever kind of speaker it is!

An inexpensive speaker does not have to be a cheap speaker. I bought my first Maggie’s in 1978, and they had one advantage over mine, heavier Mylar that was not as elastic as the present models. If you can’t look at a panel, sans sock, and immediately tell me the first thing that is wrong with it, then whatever I say will never be able to to change your mind on that matter.

The three advances in all of that time is actually only two. Lighter diaphragm and foil instead of wire. The buttons are needed to tame resonance in the diaphragm caused by the lighter more elastic material being used.

 

[josh358]

Magnepan is an acquired taste. Put a Revel speaker next to a Magnepan of the same price range and it's a world of difference. The Revel is crystal clear and highly defined while the Magnepan offers a fuzzy, reverbish sound that can be enjoyable with Diana Krall vocal music but lacks clarity with lots of other music. My best upgrade for my LRS was to get rid of them and buy the Revels. The difference in sound is Night and Day.

I have the impression you're going for something that sounds good with close-miked studio pop. That was engineered to sound good on studio monitors and cheap speakers/earbuds and I think it will sound best on dynamics. The people who like line source dipoles are people who like and are familiar with live, acoustical music. That's where the typical box falls flat on its fac, and line source dipoles excel because they sound more like the real thing.