Originally Posted by Garman
All depends on which ones you buy, they have speakers ranging from $600 a pair all the way up to $85,000.(all sound great to my ears) Now mind you I got most of mine pretty inexpensively as I use to work for a dealer that carried these.
Totally different sound between the two types of speakers! Dynaudio are accurate and very smooth and detailed. The Martin Logans are very open sounding and throw up a huge soundstage. The Martin Logans have shocked me on price verses performance, especially with there Electromotion speakers.
The Martin Logans have a huge soundstage because they are dispersing the sound as a dipole speaker. It's more reflection than true direct sound and the soundstage is a bit of an illusion. While not accurate, it certainly sounds like it has depth from the listener to beyond the speaker position.
From what I remember about the Dyn mids, they use polypropylene which would explain the "smooth" character to the sound and it's largely why I chose poly-based drivers in my home theater as well as car audio systems. Although I didn't buy expensive brands, I really think driver material plays a big role in the signature sound a speaker has. Polypropylene is often described as a material that is light, rigid, responsive yet has excellent damping but it's weakness is that it has a unoptimally low breakup frequency of 1,500Hz which makes it expensive to make a crossover network that keeps the breakup inaudible (or as imperceptible as possible). Some manufacturers add additional mass to the poly to increase damping or to reduce it's breakup distortion, but ultimately, in my opinion, it's the best sounding material ever used for drivers due to that "smooth" adjective people label it with.
Dynaudio somehow managed to make a poly-based series of mids which measure incredibly LOW in distortion tests. Dynaudio attempts to "dress up" the way they tell you about the driver material (MSP - Magnesium Silicate Polymer) but that is essentially Polypropylene, lol. I don't know how they managed that little trick as many well known brands (Infinity for one) abandoned poly material and invented their own (CMMD) driver material with a very high breakup frequency making it easy to design a cheap crossover that keeps the breakup distortion inaudible. I frankly don't hear the distortion these design engineers talk about in regards to poly. To me the material just sounds the most natural in the vocal range when playing back recorded sound. Smooth/organic, not tinny or harsh or metallic like so many other materials sound.