Magnepan LRS Speaker Review

[josh358]

My last all-Maggie system was 7.1.

Impressive!

 

[Descartes]

I bought a pair and sold them a month later! I wanted to believe the hype!

 

[DonH56]

My last all-Maggie system was 7.1.

Ditto.

 

[Newman]

due to the small'ish very live listening rooms I have had over the years so I prefer to damp (not dampen) them.

To "damp" them would make them sound wetter, surely!

 

[boonips]

Amir wrote, “…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.”

This precisely describes my 30+ years of ownership and daily use of various Magnepans, from SMGs up to the 1.6Q/R and its timbre-matched center and surround companion Magnepans of that era (c. 2000) in a 7.2 system. I did an exhaustive amount of experimentation over the years, settling on the combination of very careful room treatment and the construction and positioning of some free-standing, acoustically reflective and absorptive passive flat baffles directly behind the speakers, to dial-in decent coherence and imaging at the listening position. Once there, I could enjoy the ultra-low distortion afforded by them as compared to most speakers of the day, which was my whole point in getting interested in using them in the first place, having been spoiled by Quad ESL57 ownership.

It was quite a chore getting the Quads and the Maggie’s to play nice with the room and attenuate the multitude of little reflections/delays/echoes, etc. to approach an acceptable degree of focus, at least if I were sitting in head-in-a-vice posture.

Thank the Lord for the modern, controlled directivity approach by JBL, et. al. and newer, cleaner conventional drivers.

I have mine set up in a super reflective Listening room now. My wife and I are only using them to listen to live albums. All the reflections make you feel like you are at a concert.

They used to by my mains for my stereo/ht mix and were awful for listening to dialogue.

 

[DavidMcRoy]

I have mine set up in a super reflective Listening room now. My wife and I are only using them to listen to live albums. All the reflections make you feel like you are at a concert.

They used to by my mains for my stereo/ht mix and were awful for listening to dialogue.

In comparison to life with a modern, neutral, low-distortion speaker with more favorable radiation geometry, planar dipoles can give you a seductive and entertaining experience, like wearing rose-colored glasses. And there’s nothing wrong with that if it makes your happy.

 

[Newman]

They can….and I guess they can do the opposite, too.

 

[josh358]

In comparison to life with a modern, neutral, low-distortion speaker with more favorable radiation geometry, planar dipoles can give you a seductive and entertaining experience, like wearing rose-colored glasses. And there’s nothing wrong with that if it makes your happy.

Well, conventional speakers spill even more reverberant energy into the room, 4.8 dB, if I remember correctly, and that tends to go to the first reflection points on the sides, where it creates artificial widening of the image, just as the rear radiation of a dipole creates artificial depth. Also, omnidirectional bass triggers more room modes than dipole bass so has a rougher LF response -- a phenomenon I'm very familiar with because we've tried to design omnidirectional woofers that sound as realistic than dipole woofers, and you need four properly-positioned woofers to achieve that.

Then there's the baffle step, and the shifting of the radiation pattern as the loudspeaker shifts from monopole to cardioid as a function of frequency. I know that some (including Linkwitz, IIRC) have posited that the brain requires that the direct sound and reflections have a similar frequency balance; I'm not sure how much truth there is in this (has anyone tested it experimentally?)

Mostly, in my experience, properly set up (they rarely are) planars do a significantly better job of recreating what I hear in an actual venue, because the (artificial) reverberation isn't coming directly from the source, something that we know the ear can detect. Hell, unless you're in the first few seats and the near field, most of what you hear in a concert hall isn't direct sound at all. To my ears, dipole line sources can sound stunningly realistic on acoustical music. Omni/cardioid speakers, not so much. Where they beat planars in my experience is on small ensemble music recorded in a small studio. If I put absorption on the wall behind a planar, the sound becomes clean, detailed, and precisely imaged -- which can sound impressive, but is nothing like what acoustical music sounds like in real spaces.

Interestingly, planars are the only speakers I've ever heard that can reproduce piano, and I know that others have made the same observation.

Finally, for a given quality, planars can be significantly cheaper than boxes, though large amplifiers and subwoofers can reduce that advantage.

Which isn't to say that planars don't have their own problems! I wouldn't choose them for pop and rock -- too far from the monitors used to mix it, they expose the Frankenstein engineering, they can't match the SPL's of some dynamics, the lateral crossover lobing is problematic, only the large ones have deep bass, etc.

All interesting stuff and I'm always interested in what people have to say about it, particularly since as a planar fan and in recent years designer, I'm biased in the planar direction.

 

[DonH56]

I am not sure the actual energy injected into the room is any different; I suspect it is higher for dipoles at the same SPL due to the back wave. However, the direction of the energy (wavefront) is quite different.

 

[Newman]

conventional speakers spill even more reverberant energy into the room, 4.8 dB, if I remember correctly,

That would only be in the low frequencies where the DI of a perfect dipole is 4.8 dB and of an omni is 0 dB. Once a conventional speaker starts to beam and its DI rises above 0, the reverberant energy quantum is more similar between the speaker types.

BTW ‘spill’ is a value-laden word, how about ‘distribute’?

Also, omnidirectional bass triggers more room modes than dipole bass so has a rougher LF response

Actually the opposite: the more room modes triggered, the smoother the LF response.

…rougher LF response -- a phenomenon I'm very familiar with because we've tried to design omnidirectional woofers that sound as realistic than dipole woofers, and you need four properly-positioned woofers to achieve that.

“Very familiar”?? But I just pointed out you are wrong, so how can you be “very familiar” with something not even real?

planars do a significantly better job of recreating what I hear in an actual venue, because the (artificial) reverberation isn't coming directly from the source, something that we know the ear can detect.

?? But you just finished saying “the conventional speakers ‘spill’ more reverberant energy into the room”, therefore it is they, not the dipole, that recreates the “actual venue”… by your own logic.

most of what you hear in a concert hall isn't direct sound at all.

…and yet as you say, it is the conventional speaker that, er, ‘spills’ more indirect sound into the room…

planars are the only speakers I've ever heard that can reproduce piano, and I know that others have made the same observation.

…and I know others have made the opposite observation…

Finally, for a given quality, planars can be significantly cheaper than boxes,

I say the opposite. As post #1 shows, this speaker has pretty low ‘quality’, and some speakers even at $100 have more of ‘it’. Once you get into the expensive planars, that gap widens.

 

[Doodski]

TW ‘spill’ is a value-laden word, how about ‘distribute’?

The word propagate works too.

 

[josh358]

I am not sure the actual energy injected into the room is any different; I suspect it is higher for dipoles at the same SPL due to the back wave. However, the direction of the energy (wavefront) is quite different.

It's 4.8 dB lower because of the nulls at the sides.

 

[josh358]

That would only be in the low frequencies where the DI of a perfect dipole is 4.8 dB and of an omni is 0 dB. Once a conventional speaker starts to beam and its DI rises above 0, the reverberant energy quantum is more similar between the speaker types.

Yes, that makes sense.

BTW ‘spill’ is a value-laden word, how about ‘distribute’?

True. I'd say "contribute" is the word we want.

Actually the opposite: the more room modes triggered, the smoother the LF response.

“Very familiar”?? But I just pointed out you are wrong, so how can you be “very familiar” with something not even real?

Sorry, but we've done actual listening and measurements. We wouldn't bother with dipole bass if the response weren't smoother -- dipole cancellation makes it inefficient.

?? But you just finished saying “the conventional speakers ‘spill’ more reverberant energy into the room”, therefore it is they, not the dipole, that recreates the “actual venue”… by your own logic.

They ahem contribute it to the sides. The stage widens and since the path length difference is typically low, the sound is colored, which is why absorption is so often used at the first reflection points at the sides. For recordings made in larger venues, depth contributes more to the illusion.

…and yet as you say, it is the conventional speaker that, er, ‘spills’ more indirect sound into the room…

…and I know others have made the opposite observation…

They're wrong.

I say the opposite. As post #1 shows, this speaker has pretty low ‘quality’, and some speakers even at $100 have more of ‘it’. Once you get into the expensive planars, that gap widens.

Amir, as I recall, listened to one speaker (!) and when I asked how it was positioned, he didn't respond. I'd need to know the size of the room, too -- the LRS is a small room speaker and has no bass in a larger one owing to interaction between the baffle and room sizes; the general rule is the larger the room, the larger the baffle has to be and vice-versa.

There is a long discussion of the measurement issues which boils down to you can't measure dipoles in free space because it doesn't take into account the interaction of the loudspeaker with the room -- see Dave Reite's post. I've heard the LRS, and for the reproduction of acoustical music, I don't know of anything that comes close at that price. For rock, I'd choose a dynamic.

 

[DonH56]

It's 4.8 dB lower because of the nulls at the sides.

That neglects the energy from the back wave that also goes into the room...

 

[josh358]

That neglects the energy from the back wave that also goes into the room...

Well, see what Newman said above. It's true only of the lower frequencies where the speaker is omnidirectional. At higher frequencies where the radiation pattern is cardioid, he says that the difference between the box and the dipole is minimal. It's a good point.

 

[DonH56]

At lower frequencies virtually all speakers behave as point sources. As frequencies increase a conventional design radiates more to the front and sides whilst dipoles radiate more to the front and rear. I'll quit, no use engaging in another stoopid internet debate.

 

[NTK]

Here is a comparison of the sound power directivity indices (SPDI)** of the LRS, Genelec 8431A, and Revel M105. You can see that the LRS has higher SPDI up to ~800 Hz, which means it radiates less total sound power (relative to its on-axis output) than the 2 representative front firing speakers below ~800 Hz. Above ~800 Hz, the LRS and M105 track relatively close to each other, including the 3 kHz dip, while the 8431A SPDI curve is a lot closer to monotonic.

** Sound power directivity index is the sound intensity radiating in the [edit] on-axis direction listening window divided by the averaged (rms) sound intensity the speaker radiates in all directions.
CTA-2034 only measures the horizontal and the vertical front-back orbits, and much of the data used in the sound power calculations are interpolated. The missing data is considered less important because most of the sound we hear at the listening positions are direct sound and early reflections from the side walls, ceiling, and floor, which are originated from the speaker in its horizontal and vertical directions. The sound radiated from the speaker at the other directions take many more bounces to reach our ears and are therefore much more attenuated.

 

[josh358]

At lower frequencies virtually all speakers behave as point sources. As frequencies increase a conventional design radiates more to the front and sides whilst dipoles radiate more to the front and rear. I'll quit, no use engaging in another stoopid internet debate.

Debates aside, bear with me for a moment, because this is kind of interesting. At least I find it interesting. No debates, I promise.

We're actually talking about several things here -- point source vs. line source, and monopole vs. cardioid vs. dipole.

A conventional speaker is omnidirectional at low frequencies, then transitions to cardioid at higher frequencies as wavelength becomes small compared to the dimensions of the baffle and the sound can't diffract around it. That transition is called the baffle step.

A dipole, on the other hand, behaves roughly as a dipole at all frequencies, which is to say the radiation pattern doesn't change at the baffle step. It does have a baffle step, but it has a different effect, in that in the far field, the output decreases by 6 dB/octave below it the transition. This is known as dipole cancellation and has to be compensated for with acoustical or electronic equalization. This is why dipole speakers have to have such large baffles if they are to have good bass response.

OK, point sources vs. line sources. A line source of finite height, whether a dipole or a monopole, will behave as a point source in the far field, and as a line source in the near field. An infinite line source is always in the near field and so always acts as a line source. Interestingly, though, when the line source runs floor to ceiling, direct sound combines with the floor and ceiling reflections to approximate the radiation pattern of an infinite line source. In practice, this effect tapers off, but it still extends the line source acoustically beyond the floor and ceiling and means that the listener will always be listening in the near field. As a result, the radiation pattern remains that of a line source down to the lowest frequencies.

A point source behaves as a point source as you'd expect -- *until* frequencies are very low. At the point at which the distance between the driver and its floor and ceiling reflections is <= 1/2 the wavelength being reproduced, floor and ceiling reflections make it behave as -- a line source!

That's theory. In practice, a planar loudspeaker with acoustical equalization, like the Maggies, reproduces different frequency ranges from different heights, because it's divided vertically into resonant sections. This means that there is a region below the deepest bass and the midrange where the loudspeaker behaves as a dipole point source.

In the case of a line source that doesn't run floor to ceiling, the behavior is even more erratic. Dave Reite once measured a pair of MMG's, which are the same height as the LRS, and found that they behaved more like point sources than line sources.

Finally, it's possible to listen to even short line sources in the near field simply by moving close to them. Bass extension and output increase dramatically when you do this. With a speaker the height of the LRS, it seems to occur when you're within about 5' of the speaker.

 

[DavidMcRoy]

At this point I’d like to briefly interject into this interesting discussion that my recent experiences with modern “cardioid speakers” (I love that term for the purposes of this discussion) have been exclusively with a constant directivity design, and those are new in my experience. I’ve been amazed at how forgiving they are compared with my old Magnepan dipoles. They’re so much easier to place and their timbre changes little when heard from anywhere in the house! They really do behave uniquely. I‘ll have to bring a pair of “more conventional” conventional speakers (non-CD) back in here to refamiliarize myself with how “they” interact with the room. I’m retired from broadcast audio engineering and its been a couple of years since I’ve listened critically to any of those. I do have some in mothballs that I can drag out for a listen.

 

[josh358]

At this point I’d like to briefly interject into this interesting discussion that my recent experiences with modern “cardioid speakers” (I love that term for the purposes of this discussion) have been exclusively with a constant directivity design, and those are new in my experience. I’ve been amazed at how forgiving they are compared with my old Magnepan dipoles. They’re so much easier to place and their timbre changes little when heard from anywhere in the house! They really do behave uniquely. I‘ll have to bring a pair of “more conventional” conventional speakers (non-CD) back in here to refamiliarize myself with how “they” interact with the room. I’m retired from broadcast audio engineering and its been a couple of years since I’ve listened critically to any of those. I do have some in mothballs that I can drag out for a listen.

Interesting. I'd expect them to be easier to place, no backwave to worry about and if the beam is narrow enough, sidewall reflections wouldn't be a major issue. How low does the constant directivity extend? I'd also expect dipoles to sound the same out of the room because they have nearly ideal power response.