For my day job I work as a mechanical engineer in the aerospace industry. I design aerospace structures. I've been following this thread and was equally impressed with the improved clarity of the M600 samples. After talking with some of the other designers, dynamicists, and stress analysts I work with I think I can shed some light on the science behind this product.
Typical environmental acoustic disturbances due to mechanical vibrations such as traffic, heavy machinery, and seismic energy, live in the subsonic and infrasonic frequency ranges. The largest amplitudes of noise from these sources are present below ~100 Hz. Traditional shockmounts use elastic suspension to isolate the mic from subsonic disturbances. However, the resonant or natural frequency of these elastic bands is most likely on the order of 10 Hz (give or take). The mic is therefore decoupled from subsonic energy like foot stomps that may make their way up through a mic stand. However, the resonant frequency of the elastic is likely still in a range where it can couple with the infrasonic disturbances I have mentioned. When two structures have natural frequencies that are relatively close to one another you can get large constructive interference. This is why old bridges get excited and practically self destruct in earthquakes. Another good analogy would be what happens acoustically in a listening room. The room has a certain modal response based on its dimensions. Let’s say that the first mode of the room is 40 Hz. When you play a 40 Hz tone the room is excited and in certain locations you hear much more 40 Hz than there really is. The same thing happens with the elastic shockmount. At infrasonic frequencies close to the resonant frequency of the elastic bands the shockmount is actually excited by the acoustic loads. This coupling causes the infrasonic frequencies to mask frequencies in high octaves. That’s why you hear the traditionally shockmounted mic as congested and less open.
The Enhanced Audio design is structurally much stiffer and holds the mic much more rigidly. The naturally frequency of the coupled Enhanced Audio shockmount and microphone system is orders of magnitude higher than the elastic suspension shockmount. It’s natural frequency is most likely high enough to be outside of the frequency band where the abundance of infrasonic and subsonic energy lives. So when these low level disturbances make their way to the mic they do not couple with or excite the shockmount/mic system. This shock isolation design is very typical in the aerospace industry when you want to structurally isolate an electronics component. You typically design the isolator such that its naturally frequency is orders of magnitude less than offending/harmful frequencies you are trying to protect the electronics from.
The following statement on the Enhanced Audio website is slightly misleading though.
The Enhanced Audio M600 breaks away from the convention of suspension mounting by clamping the microphone within two low resonant aluminium rings
The aluminum rings look actually very stiff, so their resonant frequency (natural frequency) would most likely not be very low, but actually rather high as I have already stated.
The website also states the following:
Theory is one thing, reality another, technical specifications are important but we believe that there is nothing that goes beyond your own personal experience and listening with your own ears.
Well now everyone knows the theory of why this thing works the way it does. There actually is science behind it all. So it’s probably not good marketing to play on “audio voodoo” anymore.
David Browne—I’ll gladly accept any freebies you’d like to send me if you’d like to use this explanation on your website.
Brad