Why Do Martin Logan Speakers Lack Dynamic Energy?

Dynamics is a function of moving air rapidly. Your perception is correct. I too had the same concern--I also own a pair of Monoliths that have been modified (a lot).

First, a large planar such as a monolith can absolutely move a lot of air rapidly, however, you have to look at how it's focused to the listener. Fact is--it's not. The room can be designed to specifically account for this and focus the back wave kinetic energy towards the listener--thereby increasing the dynamics. However, what happens to the bass--nothing in that scenario. This has been one of the main difficulties with hybrids. They have the so called promise of "dynamics of a full dynamic speaker transparency of an electrostatic", but in general don't deliver.

One of the problems is cost. The basic issue can be overcome and has been proven with the Statement--but $80k--well it better do just about everything perfect and paint my house too.

Before I get into methods to overcome, you should probably just consider the very basic issue here first. Dynamics are perceived by kinetic air movement focused at the listener--it's that simple. What focuses energy at the listener best? A horn. What focuses energy the least? A planar, and particularly one that is curvilinear spreading out the energy to all directions.

Let's say both a horn and a planar can deliver the same amount of air movement for 1 watt of power, but the horn is focused, where as the planar is not. Let's say the room has no losses--all energy gets to the listener (eventually). What is the perception--it hasn't changed. The direct energy of the horn is very dynamic. The indirect and more diffuse sound field of the planar is far less dynamic, but to a large degree more etherial. Many of us like this room interaction that gives us a sense of space and imagery. I personally like it, and although I've owned horns--I am willing to sacrifice the dynamics for the transparency and imaging.

Now on to what can be done. ML uses woofers that integrate will with their speakers and don't cost obscene amounts of money. As I said previously--I modified mine. The panel was fabulous--the bass wasn't. It was slow and undefined and did not give me the dynamics I wanted in the lower octaves. So I changed it--it's not so simple. I had to bi-amp with an active cross over that was pretty flexible and bipass the internal cross over. The engineers at ML were kind enough to help me with the loading of the new woofers which were Focal Audiom. The results were spectacular--but as the saying goes "don't try this at home".

This excellent explanation was emailed to me by "lrsky".

"As former Director of Sales for a competing line of Martin Logan, and
previous owner, 20 year industry veteran, I believe I can answer your
question.
Dynamic drivers punch a small (relatively) diameter of air a great
(relative to Electrostatics) distance. Example, the midrange driver slaps
the air forward the greater part of an inch (the actual distance the
driver travels is very speaker dependant). This abrupt slam, creates sound
and a percussive, resulting, dynamic moment. (Think air rushing back
into the void after a lightning strike) Conversely, when an electrostatic
is called on to make the same tonal sound, a large panel, many times
larger than the dynamic drivers, moves forward, fractionally as far as
the dynamic driver. This Electrostatic displacement creates the same
tone, and set of harmonic information, but the lack of that dramatic slam
of air displacement gives it an overall, more polite sound.
Imagine, cupping your hand, against the water in a pool, and pushing
down. The result is that you displace the amount of water proportionate
to the size of your hand. Now do the same thing, smacking the same
amount of water, simply raising your hand a few inches away. There is a
whack which is loud and startling, verses very little sound, even though
you have displaced the same amount of water. (This is really simplistic,
but ok for a quick look)
On the plus side, some people ask, "How can a small tweeter, midrange
and woofer can create the lifelike size of a piano, compared to a three
feet by five foot, panel, which is certainly more nearly the actual
size of that piano.
This is an example of almost oppostite approaches to accomplish the
same thing. Finesse, versus raw energy. Which one is better, is wholly a
function of your tastes and sometimes, unfortunately your reference. I
say unfortunately, since many people think that their current speakers,
however poor they may be, sound correct, since it has been their
reference point for so long.
I owned the Prodigys, which are the $11K ML speakers, and thought them
to be very good. Fast smooth, and with the two conventional woofers,
ofered good bass, with nice blending of the two disparate technologies.
Plus, Gayle Sanders is an acquaintence of mine, and I have been to his
home. He gives a good honest value for the price. Listen carefully to
those speakers which you narrow your choices down to. Any flaws you hear
in q quick demonstration, become multiplied, and exagerrated,
exponentially over time. If you're an audio nut like me, the flaws are all you
CAN hear once you've identified them! HA!"

You already post this at the Martinloganowners.com forum page just recently isn't it?

(http://martinloganowners.com/forum/messages/2413.html)

I am glad you finally found your answer. That thread is loonnnnggg!

I have used the original Quad, Acoustat 2+2, and Martin Logan CLS as midrange reference transducers over the past 27 years. I like their lack of cabinet resonance and single-driver coherence; however, they all exhibit tremendous dynamic compression from a mechanical standpoint. At Cal Tech, we used a laser interferometry setup to measure the dynamic range as referenced to excursion potential vs. voltage. As the electrostatic diaphragms are stretched very tightly and have no elastic edge surround, they have a finite limitation on excursion potential, no matter how much more voltage you input. Initially, the diaphragm will move on a 1:1 scale, but rapidly, the excursion does not follow the input voltage, resulting in a very high degree of compression of the signal. This is the source of "lack" of dynamic range that most listeners pick up on. Most cone systems do not compress until very high volume levels are reached.
Albert Von Schweikert

Albertvonn, thanks for the very informative post. At what volume levels did the compression start to set occur?