Piezoelectric bender with additional constructive resonance

A sound source comprising:

• a pair of flexible base plates configured to bend and generate acoustic energy, wherein the pair of flexible base plates are spaced to provide a gap between their respective inner surfaces, wherein each of the pair of flexible base plates comprises:
• a spring coupled to an inner surface of the corresponding one of the pair of flexible base plates;
• and
• a mass element coupled to the spring, wherein the spring and the mass element are located in the gap between the pair of flexible base plates, wherein the sound source is operable to produce at least two resonance frequencies between about 1 Hz and about 100 Hz at a depth in a body of water of about 0 meters to about 120 meters.

An apparatus comprising:

• a plurality of sound sources arranged in a stack, wherein the sound sources each comprise a pair of flexible base plates configured to bend and generate acoustic energy, wherein the pair of flexible base plates are spaced to provide a gap between their respective inner surfaces, wherein each of the flexible base plates comprises:
• a spring coupled to an inner surface of the corresponding one of the flexible base plates;
• and
• a mass element coupled to the spring, wherein the spring and the mass element are located in the gap between the pair of flexible base plates;
• wherein the plurality of sound sources are operable to produce at least two resonance frequencies in the apparatus, wherein at least one of the two resonance frequencies is about 10 Hz or lower at a depth of the sound source in a body of water of from about 0 meters to about 120 meters.

A sound source comprising:

• a base plate configured to bend and generate acoustic energy;
• a spring coupled to the base plate;
• a mass element coupled to the spring;
• and
• a spacer disposed between the spring and the base plate, such that the spring is indirectly coupled to the base plate, wherein the spacer comprises a disk, wherein the spring comprises a disk, and wherein the mass element comprises an annular disk coupled at a perimeter of the spring, wherein the sound source is operable to produce at least two resonance frequencies in the sound source.

A sound source comprising:

• a base plate configured to bend and generate acoustic energy;
• a spring coupled to the base plate;
• and
• a mass element coupled to the spring, wherein the spring comprises a disk, wherein the mass element comprises an annular disk coupled at a perimeter of the spring, wherein the sound source is operable to produce at least two resonance frequencies in the sound source.