Microphone - Prototype
The Cardas Golden Ellipsoid Microphone 5813-01

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Overview

All current diaphragm microphones use either round, or in one rare case, a rectangular diaphragm. These designs all have a recurring cord length, based on the diameter, radius or parallel walls of the diaphragm. This creates a predictable tensioning of the diaphragm as pressure is applied and a predictable reflection from the face of the microphone as the pressure wave passes. As a result, existing large diaphragm microphones have predictable time delays and native resonances in the audio spectrum. Terminating the diaphragm edges to a logarithmic curve diversifies the diaphragm cord length and its characteristic time delays and resonances. This unique shape smoothes and improves off axis response.

Due to the Golden Ellipsoid Microphone's unique shape, the labyrinth acoustic Low Pass Filter, formed by the dual back plate, traditional round capsule resonances at filter cutoff points are reduced, minimized, eliminated, broadened in slope, lengthened or softened. The precedent for elliptical porting of loudspeakers is similar. This results in a more accurate or cleaner impulse response at all frequencies. Because of this reduced resonance at the critical frequency crossover point, where the High Pass Filter and Low Pass Filter functions of a directional microphone model create it's directionality, a flatter frequency response is achieved to a lower frequency than by traditional means.

Normal diffraction effects are avoided since the edges of the capsule intercept continuously varying portions of oncoming High frequency waves, contrary to traditional static or fixed interception of wave forms which create high-Q factor resonant peaks.

In practice this microphone allows for the maintaining of relatively flat frequency response in the off axis, while in directional mode, without having to place the front to rear path length above or in the higher regions of the audio band. Thus retains the lower noise usefulness of a larger diaphragm capsule.

The Patent for this microphone claims three basic shapes that achieve this goal.

The Ellipse: An oval shape that is basically four joined, logarithmic curves. This shape includes the Golden Ellipsoid, an ellipse wherein the major and minor diameters progress in Golden Ratio or 1.62 to 1

The Horn or Nautilus: This shape is two logarithmic spirals nested one with in the other.

The Tear Drop: The basic outline of a Nautilus.