Minimum Diffraction Coaxial (MDC™) Driver Technology

Minimum Diffraction Coaxial (MDC™) transducer reproduces outstanding sound image.

Typical to all current coaxial designs is somewhat ragged frequency response due to inherent diffraction problems. However, crossover issues due to non-coincident location of sources are solved with a coaxial configuration. Here lay the seeds of Genelec’s Minimum Diffraction Coaxial (MDC™) solution: while it benefits from typical coaxial design advantages, it now overcomes their serious shortages as well.

The first step is to minimize the cone displacement, in other words to limit the low frequency bandwidth of the driver. Next, is to avoid all sources of diffractions. The main structure of the MDC design consists of an integrated MF diaphragm-suspension- tweeter construction. The visible part of the coaxial driver is formed by the curved flexible skin with the dome tweeter assembly in its centre. The inner section joins the cone to the tweeter without any acoustical discontinuity, and the outer one does the same between the cone and the driver chassis.

mdc exploded

As there are no acoustically observable discontinuities between the tweeter and the cone, just a smooth surface, there is no diffraction either. The cone profile is very carefully optimized to form an integrated directivity control waveguide for the tweeter radiation. The driver outer edge is terminated to a normal Genelec DCW in order to control the dispersion of midrange radiation as well. The response is very smooth both on and off-axis and free from any anomalies and directivity is well controlled.

This breakthrough in coaxial design provides improved imaging and overall sound quality on- and off-axis, extremely smooth frequency response leading to outstanding clarity and definition of the inner details of the music.

mdc detailed comments

The main novelties of Genelec combined DCW™ and MDC™ designs:

  • Diffraction-free joint between tweeter and midrange diaphragm
  • Diffraction-free joint between midrange diaphragm and DCW™ waveguide
  • A proprietary midrange diaphragm technology – laminate structure combining a rigid cone and elastic, lossy materials including the suspension itself
  • A midrange diaphragm-suspension pair which cancels all possible non-linearity


  • Smoother frequency response
  • Ensures the drivers to couple coherently over their full operating bandwidth
  • Significantly improves the directivity control in the critical frequency range
  • Provides balanced suspension dynamics to minimize acoustic distortion
  • Optimizes the use of the front baffle area while maintaining the 8000 series appearance and benefits