Permission to Land!

CDX20-3075 2" exit, 3" diameter voice coil, ferrite magnet compression driver.

July 12, 2013

This is our 2" exit compression driver the CDX20-3075. From some angles we think it looks a bit like a UFO, thanks to a sizable ferrite ring magnet that "fuels" the generous 75Wrms power handling and 107dB sensitivity.

The driver features our patented phase plug.

A phase plug, for those unfamiliar, sits in between the diaphragm and the horn throat, filling the cavity volume and extending the desired level of output efficiency to higher frequencies. Through the years a number of methods have been used to design phase plugs, in the search for improved performance, the most recent and prevalent version having been adopted as long ago the late 70s.

The Celestion innovation completely re-designs the the size and location of the phase plug slots that enable the sound waves to freely travel from diaphragm to the driver's throat.

The slot positions have been mathematically optimised to minimise the instance of unwanted cavity resonances (reducing non-linearity) and lower the compression ratio (increasing efficiency).

The new-style phase plug is designed to work in conjunction with a deeper-than-standard titanium diaphragm. This increase in depth adds stiffness, so the new diaphragm exhibits its first modal break up at a higher frequency when compared to a typical compression driver diaphragm (which starts break up in the 8-10kHz range). The result is exceptionally low distortion HF sound reproduction.

No hiss = acoustical bliss.
Back to PA Tech