Planar diaphragm loudspeaker with counteractive weights

In a loudspeaker including a planar diaphragm and a voice coil assembly, the diaphragm having a front surface for the reproduction of sound and a rear surface to which the voice coil assembly is coupled to cause the diaphragm to vibrate, the improvement comprising:

• a plurality of weights;
• a plurality of boundary walls, each boundary wall defining a recess in the rear surface of the diaphragm in a prescribed pattern;
• and
• a resilient material within each of the plurality of recesses, separate and distinct from the weights,
• wherein said each recess is sized to receive a weight of said plurality weights with a clearance fit providing space between the weight and the boundary wall of the recess, and further wherein said each weight is embedded in the resilient material within the recess to enable the weight a degree of movement relative to the diaphragm, such that the weights help control the response characteristics of the diaphragm at various frequencies.

A loudspeaker for the reproduction of sound, comprising:

• a planar diaphragm having a front surface for the reproduction of sound and a rear surface;
• a voice coil assembly coupled to the rear surface to cause the diaphragm to vibrate and reproduce sound at its front surface, wherein the characteristic frequency response of the diaphragm has peaks and valleys with respect to a flat frequency response;
• a weight;
• a boundary wall defining a recess in the rear surface of the diaphragm, the recess sized to receive the weight with a clearance fit;
• and
• a resilient material within the recess, separate and distinct from the weight,
• wherein the weight is encased in the resilient material, the resilient material and suspending the weight within the recess, with the weight spaces from the boundary wall defining the recess to permit the weight a certain amount of movement relative to the diaphragm so that the weight counters the vibrations of the diaphragm at certain frequencies and enhances the vibrations of the diaphragm at other frequencies, and
• wherein the weight is sized and the recess located so that the weight counters the vibrations of the diaphragm at a frequency associated with a peak in the characteristic frequency response of the diaphrams and the weight enhances the vibrations of the diaphram at a frequency associated with a valley in the characteristic frequency response of the diaphram to flatten the weighted frequency response of the diaphram.

A method for reproducing sound, comprising:

• providing a planar diaphragm having a front surface for the reproduction of sound and a rear surface;
• vibrating the rear surface of the diaphram to cause the front surface of the diaphram to reproduce sound, wherein the characteristic frequency response of the diaphram has peaks and valleys with respect to a flat frequency response;
• providing a weight;
• providing a boundary wall defining a recess in the rear surface of the diaphragm, the recess sized to receive the weight with a clearance fit;
• embedding the weight in a resilient material, separate and distinct from the weight, to hold the weight in the recess, but spaced from the boundary wall defining the recess to permit the weight a certain amount of movement relative to the diaphragm, so that the weight counters the vibrations of the diaphragm at certain frequencies and enhances the vibrations of the diaphram at other frequencies;
• and
• sizing and locating the weight, and the recess, so that the weight counters the vibrations of the diaphram at a frequency associated with a peak in the characteristic frequency response of the diaphram and the weight enhances the vibrations of the diaphram at a frequency associated with a valley in the diaphragm's characteristic frequency response of the diaphragm to flatten the weighted frequency response of the diaphragm.