Martin Logan - wow


I heard my first electrostatic speakers yesterday, ML Ascent at a very helpful dealer. These are clearly my cup of tea -- I liked better than the B&W N802s I listened to at the same time. Vocals are amazingly present. So of course I have some questions:

1. The bass wasn't great. Better than a monitor (I listened to B&W N805) but not much punch, and more important, sounded a little sloppy. Are there adjustments that one makes to the crossover, some little magic knob, that might improve this?

2. Are most users combining with a sub for stereo use (I'm not doing HT)?

3. We listened in a small room (about 8x8) at the store. My room is about 25 x 14 x 8', with speakers along the 14' wall. What model of Martin Logan would do the best job in this room? Bigger, smaller? I mostly listen at low-ish volumes, but would like to crank it ocassionally?

4. My amp is a Classe CA-200 (the newer style, same as current CA-201). Will this amp do justice to the speakers?

5. Other speakers I should listen to? I hear "maggies" and "innersound" -- are there others to consider?

Thank you!
ehart

Showing 2 responses by audiokinesis

Greetings Ehart -

And welcome to the wonderful world of electrostats!

There are several different flavors out there. Let me describe four of them for you, and you can see what direction makes the most sense for you.

1. InnerSound - These are probably the best-imaging and have the best dynamic impact of all the electrostats. The bass is very adjustable, which is important to get a good blend between panel and woofer. The downside is a very small sweet spot - but this may not matter to you, depending on your listening habits.

2. Martin Logan - The Martins give you a wider sweet spot than the InnerSounds, and are generally very elegant in appearance. Rather than build one or two models with lots of adjustments, Martin Logan builds a wide variety of models. It's important to match up the right size speaker for your room, to get the woofer/panel balance correct (I'll talk a bit more about the challenges of woofer/panel integration a bit later on). In a fairly large room like yours, the Prodigy would probably be the best choice, but the Odyssey still would work well.

3. Quad makes a couple of full-range electrostats. While they don't play as loud as the Martins and InnerSounds, they have a lovely coherence that isn't possible to get from a hybrid. I've owned several earlier model Quads.

4. Sound Lab makes some rather large full-range electrostats. They are the least efficient and probably most difficult to drive of them all. The have a rich, lush presentation and an extremely wide sweet spot (unique among current production electrostats). I own and sell Sound Labs.

Note that if you choose to go with electrostats, you must give them plenty of room behind the speaker. You may have to treat the backwave a bit - I like to use diffusion, and avoid absorption except as a last result.

Also, amplifier matching is much more critical with electrostats than with dynamic speakers. Fortunately, you're starting out with a very nice amplifier, and it may well suit your needs (I have no first-hand experience pairing up that amp with electrostats).

Let me describe one of the challenges of integrating an electrostatic panel with a dynamic woofer (there are many challenges involved, but I'm only going to focus on one here). The panel approximates a line source (sound radiating cylindrically from an infinitely tall, thin line), while the woofer approximates a point source (sound radiating omnidirectionally from a tiny point). Sound pressure level falls off with the square of distance from a point source, but linearly with distance from a line source. Let me use an illustration to explain:

Suppose your woofer is putting out 90 dB at one meter in an anechoic chamber. Move back to 10 meters, and the sound pressure level is now 70 dB. But for a line-source panel that's putting out 90 dB at one meter, the sound pressure level will only fall off to 80 dB at 10 meters! So what the designer has to do is voice the speaker for correct tonal balance at the anticipated listening distance. Too close and the woofer is too loud; too far back and the panel is too loud.

In a real-world room this discrepancy isn't quite as bad as the theory predicts, but it's still there. I once measured a hybrid electrostat in my room at 1 meter, 3 meters (the listening position), and back at 8 meters (maximum practical distance). At one meter, the woofer was up by 1 dB. At 3 meters, the output measured the same for both woofer and panel (no joke - and they had been adjusted by ear). Back at 8 meters, the panel was 4 dB louder than the woofer. So, at large listening distances, this speaker would sound a bit bright and forward. So I hope you can see the importance of matching the right size speaker to the room, or of dialing in the right level setting for the woofer (depending on which brand you end up with).

Finally, you asked about Maggies. Maggies are full-range planar magnetic speakers, not electrostats, though they have much in common with them. Maggies are an easier load to drive than electrostats (though their efficiency is still low and they also like lots of power). Electrostats are often a bit more articulate than Maggies, especially at low volume levels, but Maggies are very nicely voiced and since they don't use dynamic woofers, they are generally more coherent than a hybrid electrostat.

Between these five manufacturers, chances are there's a speaker that you will fall in love with and perhaps never desire to replace. Without knowing more about your personal preferences I can't make a reliable recommendation, but the more different planars you can listen to, the better-informed your final decision will be.

Best of luck to you in your quest!

Duke
Plato -

The low-frequency resonance phenomenon you mention can indeed produce a very significant response peak if it isn't adequately addressed.

Roger West of Sound Lab uses a patented technique called "distributed resonance", wherein he divides up each of the seven vertical facets into 12 cells. Each cell is the same width, but of a different height - hence each has a different drum-head resonance. By carefully staggering these resonances, not only is the overall response smoothed but it's extended a bit lower than it normally would go. The result is excellent pitch definition in the bottom octaves (one customer, a concert violinist, told me that the Sound Labs were the only speaker he'd ever heard properly reproduce both cello and double-bass).

Martin-Logan also used a version of distributed resonance on the CLS - that's the purpose of those divisions you see on the panel.

The concentric rings of the Quads probably also distributes the drumhead resonances a bit, though not as precisely as the Sound Lab technique does. To my ears, the bass of the 989 is less coherent than the bass of the smaller 988 - perhaps the additional bass radiating area of the 989 suffers from low-frequency diaphragm resonances?

If I'm not mistaken, Magnepan tunes their panels so that the resonant peak occurs below the normal dipole roll-off frequency, and thereby extends the bass deeper than it normally would have gone.

Obviously, hybrids don't have to worry about low-frequency diaphragm drumhead resonances, but they do have box colorations and radiation pattern incongruities to deal with. My vote is for full-range panels, where practical.

Esoxhntr, congrats on being a CLS owner! In my opinion, that's the most physically beautiful loudspeaker ever made. And they sound wonderful as well. The CLS was my favorite Martin Logan speaker, and I sure was sad to see it go. I spend some time talking with Gale Sanders a couple of nights ago, and tried to convince him to bring back something along the lines of the CLS.

Duke