Thin Ply Carbon Diaphragms -Application Examples

The combination of ultralight weight, high stiffness and controlled break up behavior enables thin ply carbon diaphragms to be used in mid- to high frequency applications: tweeters, compression drivers, midranges, full-ranges and headphone diaphragms. Larger woofers and sub-woofers with specific requirements on high break up or flatter geometries have also proven successful.

The high-resolution thin ply carbon diaphragm tweeter

One customer had an aluminum alloy tweeter and wanted to reach the high-resolution target of a 40 kHz break up. The aluminum alloy diaphragm could reach just around 25 kHz. Simulations for thin ply carbon diaphragms showed very promising results indicating a break up frequency above the 40 kHz target while staying below the original diaphragm’s weight and it was decided that prototypes were to be made, measured and listened to. After being built into drivers, the thin ply carbon diaphragms did show an increased break up frequency compared to the original diaphragms but not to the extent the simulations showed. A deeper analysis however showed that it was not the thin ply carbon diaphragms that did break up, it was the voice coil former. After a new assembly was made using a higher performance former, the measurements matched the simulations and a break up frequency meeting the 40 kHz high resolution target was met.

 

The fullrange with pistonic movement above the audible frequency range

Another customer had an aluminum fullrange with a severe break up well within the audible frequency range. The break up also resulted in clearly audible harmonic distortion at lower frequencies. The customer wanted to know if it was possible to push the break up outside the audible frequency range (above 20 kHz) as well as making it smoother to reduce harmonic distortion. The thin ply carbon diaphragm was able to achieve pistonic movement above 20 kHz. Thanks to the distributed and smoother break up, harmonic distortion at lower frequencies were dramatically reduced for a clear and smooth sound.

 

The compression driver with increased break up and without harshness

A leading pro-audio company wanted to see whether thin ply carbon diaphragms could help them improve the sound quality of their three inch compression drivers that were using a titanium diaphragm. Main targets were to increase the break up frequency above the audible frequency range and get rid of the harshness of the titanium diaphragm. Thin ply carbon diaphragms were engineered and produced by Oxeon to match the desired properties of the pro-audio company. The result was a break up frequency that was increased from 13 kHz to above 20 kHz. The sound quality was considerably improved through a more controlled break up behavior for a clear and smooth sound without harshness.

 

The upgrade of the premium Kevlar midrange cone

An audio company wanted to evaluate the potential of thin ply carbon diaphragms on their premium midrange drivers compared to their current aramid (Kevlar cones). The company wanted to maintain the sensitivity (weight) of the existing aramid cone but wanted a higher speed of sound and a higher break up frequency. The thin ply carbon cones showed a 100 percent increase in break up frequency but most importantly the sound was cleaner, more detailed and had a better room representation. Details in the music that were not audible in the aramid cones, for instance the light tap on the cymbal, were now clearly heard using the thin ply carbon cones. The placement of the musicians were much clearer with no “holes” in the room representation.