We exclusively design and manufacture HiFi-loudspeakers equipped with sensors and motion control. Through research,development and manufacturing at our facility in Zweibrücken (Germany), we have gained unique expertise and experience in this technology.




Perhaps that is why, for over 30 years, we habe been the insider's secret for people seeking the clearest music reproduction.

The feedback circuit linearizes the characteristic curve between driving current and voice coil travel.

Since we know the movement of the diaphragm (thanks to the sensors!), we are able to compensate for the variable transit time of the sound wave from loudspeaker to listener, i.e., the audible frequency variations. This unique feature is an invention of ours and lets become the reproduction of musical instruments free and clearly separated.






Early motion-control devices emphasized that this method could overcome the limitations imposed by enlosure size.

Today, however, frequency an phase responses can be adjusted as desired using digital filters, without the need of sensors. And the fact, that this results in harmonic distortion is often seen as an advatage, since it can be used to produce a warm, smooth sound.

Even though harmonic distortions might be described as pleasant, they do have a less appealing side: They are associated with intermodulations, which are rather disharmonic from both a technical and a musical perspective. They let sparate sounds become dependent on each other and this is a crucial difference between natural sound and its reproduction by a speaker.


They are (like HD) caused by the nonlinearity in the drivers voice coil and magnet and our goal is to linearize this curve using accelerometers. We love accelerometers because they use a particularly precise principle and are not subject to the frequency-dependent dynamics.


The relation between electric current and mechanical displacement of the diaphragm is not linear and shows significant hysteresis.


(Picture:Laser distance-measurement on a common 8-inch woofer, blue: how it should be)






The setup consisted of a 6-inch driver, fed at three frequencies simultaneously and with a motion conrol, that was so modified, that the sensors could be turned on and off. (microphone in the near field.)


 
intermodulation products without sensor control (left) and sensor turned on (right).

Intermodulation drops to inaudible levels, and as a side effect harmonics and resonances too.

Because we achieve very high gain in the control loop, the improvement is remarkable.

You can hear clearly now.






left:

FM3
2-ways, 3 amplifiers, h 47cm, w 18cm, d 27cm.
Price: € 9.800,- /pair

middle:

FM7
4-ways, 9 amplifiers, h 168cm, w 30cm, d 51cm.
Price: € 48.000 /pair

right:

FM5
3-way3, 5 amplifiers, h 141 cm, w 18cm, d 27cm.
Price: € 16.400.- /pair.

(Export prices excl. VAT, plus freight charges.)