Flextensional transducers and methods of using flextensional transducers. The transducer includes a piezoelectric element and may include at least one endcap coupled with the piezoelectric element. The endcap may have an outer portion formed of a first material and an inner portion formed of a second material having a greater flexibility than the first material. The endcap may be coupled with an annular piezoelectric element near either its outer circumference or its inner circumference. The piezoelectric element may be a planar disk or have a curved bowl-shape. The transducer may be coupled with, and at least partially restrained by, a support structure. The transducer may also be configured to permit light to pass therethrough.

There is provided a portable terminal capable of acquiring sound information successfully simply by being brought near to or into contact with the ear without the necessity of careful handling. The portable terminal includes at least a vibration member having a first surface exposed to an exterior, a vibration element operative to vibrate the vibration member in response to an electric signal corresponding to sound information, and electronic circuitry that outputs the electric signal, a difference in amplitude between individual places within the first surface of the vibration member in a vibrating state being less than or equal to 60 dB in terms of a ratio of maximum value to minimum value of amplitude. A portable terminal can be obtained that is capable of acquiring sound information successfully simply by being brought near to or into contact with the ear without the necessity of careful handling.

Embodiments related to restriction of gas flow in a marine acoustic vibrator to compensate for gas spring effects. An embodiment provides a marine acoustic vibrator, comprising: an outer shell; and a variable gas flow restrictor disposed within the outer shell; wherein the marine acoustic vibrator has a resonance frequency selectable based at least in part on the variable gas flow restrictor.

An apparatus includes a touchscreen keypad and one or more devices that generate a tactile response to a user of the apparatus when a key in the keypad is pressed. In order accomplish a simple construction requiring a minimum of space, the one or more devices that generate that tactile response may include at least one piezoelectric element configured to generate vibration which is forwarded to the user in response to a key of the touchscreen keypad being pressed.

Embodiments related to sound sources for marine geophysical surveys. An embodiment provides a sound source, comprising: an outer shell containing a first gas at a first gas pressure; and a compliance chamber in indirect fluid communication with the first gas, the compliance chamber containing a second gas at a second gas pressure, wherein the second gas pressure is lower than the first gas pressure. An embodiment provides a sound source for marine geophysical surveys, comprising: an outer shell; a mass coupled to the outer shell; and an actuator coupled to the outer shell. Additional apparatus and methods are disclosed herein.

Embodiments related to marine acoustic vibrator for marine geophysical surveys. An embodiment may include an apparatus, wherein the apparatus may comprise: a coil element comprising a coil; a coil clamp constraining motion of the coil element in at least one direction; and a spring disposed in a load path of the coil clamp. Additional apparatus and methods are disclosed herein.

An apparatus for generating acoustic waves in an aquatic environment through the use of linear motors mounted on a frame is disclosed herein. The linear motors can reciprocate at a first frequency which is transmitted through a transmission element and to a sound emitting surface. The structure of the apparatus can generate acoustic waves across a broad frequency to measure subterranean formations.