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Technology - Electro Magnetic Suspension



This chapter is the most important one if you want to understand why the sound of our speaker is so wonderfully musical, pure and detailed. We hope you will enjoy reading and especially you will understand.

Please remember that ANY electrodynamic driver in the world suffers these problems. Among all different types there are better ones but even the best suffer these non-linearities.

The use of electro-magnetic suspension has remarkable advantages compared to the classic mechanical suspension

  • 100% free of resonance in the audible freq. band. 

  • >99,5% linear

  • Adaptable damping of the cone (5 selections) in relation to the damping factor of your amplifier for a perfect marriage

    • We have included the possibility to choose between 5 possible damping factors. For instance, on powerful solid state monoblocks recommend 3 (basic setting). On a class A triode tube amp  we recommend selection 4 because the tube amp has wonderful 2th harmonics but lacks some control over the driver due to low damping of tube amps. On a 300B tube amp some will even select position 5.

We will analyse this graph together with you because it perfectly shows the difference between a mechanic suspension (purple) and our electromagnetic suspension (red) :

We first study non-linear behaviour (distortion)

In this graph you clearly see the non-linearity of the mechanical suspension (the purple line). The more the cone moves (x-axis) the more energy (ampères, y-axis) it relatively requires to be moved equally further.

Our EM (electro magnetic) suspension (red) is perfectly linear. Each millimeter of movement requires an exact equal increase in current. 

Maybe an example by numbers will explain it more clearly :

If you reed the purple curve (for mechanical suspension) you'll see that 1mm of movement equals approximately 0,2A of current.

If a driver was linear you should expect that for 2mm of movement 0,4A (2 times 0,2) is required, right?

But look at the graph. It shows that for 2mm of movement you need almost 0,6A of current. Talking about a non-linearity here!


Now we explain why this is so bad.

In reality if the music signal is twice as strong your amplifier will send 0,4A instead of 0,2A. So you should expect the cone to move twice as far (and generate a sine wave twice as big). But it doesn't. Because looking at the graph it will move only about 1,6mm instead of 2mm. Thus creating a smaller sine wave than what's on the recording. This is what is called "compression". The cone can't move freely and is restrained by the mechanical suspension of spider and surround. The louder you play or the stronger the dynamics in the music get, the worser the effect gets. 

This is why the dynamic response of our driver is so much better than the one of classic drivers, no matter how good they are. Our LEMS driver has no compression at all because it's more than 99% linear.

Now we study energy absorbtion (or loss of detail)

If you look carefully at the graph you'll see that the lowest point of the purple line doesn't touch the "0"-point on the x-axis. This means if you put a very small signal (micro detail) of energy in the driver it doesn't move at all. Otherwise stated : your detail (small signal) is lost.


Once again we will show it with an example by numbers.

Check on the graph below what would happen if we put 0,05A of current in the driver?

Right, the cone moves 0,00mm! Yes, you are right. This small signal (let's call it detail) is completely absorbed by the mechanical suspension! 

The same happens at larger excursions of the cone. Spider and surround will absorb more and more energy as they are pulling harder and harder to get the cone back on it's "0"-point. That's because the excursion is stretching the spider and surround more and more. This is also the compression explained before. With normal speakers this is what audiophiles often describe as "the detail is pushed away to the background" by the lower frequency's.​​​​

Now take a look at the graph of our EM suspension :

  • It's completely linear (the red line is a straight line), so it has no compression

  • It does not absorb energy because it moves with every 0.01A of energy you put into it and because our cone floats freely in the air this movement starts already at point "0".

Therefore our driver with LEMS (linear excursion motor system) motor is the world's best. We hope we have sufficiently explained why. It's not because of some vague special characteristics of esoteric materials. It's because we reinvented the electrodynamic driver by completely eliminating the source of these problems instead of trying to cure them. 

If this page was of interest to you and you want to know more about loudspeaker non-linearities you can check the internet for "Klippel Loudspeaker Non-linearities". This is an extensive research paper describing all non-linearities of electrodynamic drivers. It was of great inspiration to us while developing our LEMS technique.

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