An electroacoustic transducer for generating an audible acoustic signal includes a base, a cathode having a plurality of cathode discharge elements arranged into an array of cathode discharge elements disposed around an axis associated with the cathode and mounted on the base, and an anode having a plurality of anode discharge elements arranged into an array of anode discharge elements disposed around an axis associated with the anode and mounted on the base. An inter-electrode space separates the cathode and the anode. A first circuit portion connects the cathode to a voltage source, and a second circuit portion connects the anode to the voltage source. The cathode and anode discharge elements extend from the base toward the inter-electrode space. Respective arrays of the cathode and anode are opposite of each other with respect to the inter-electrode space and axisymmetric such that the cathode axis is aligned with the anode axis.

A speaker (10) comprises an enclosure (8) defining an internal volume (11); and at least one sound generator (7), the sound generator (7) comprising one or more surfaces defining an air-path conduit (15) through which air operably passes in and out of the internal volume. The sound generator (7) further comprises a plurality of electrodes comprising at least one air-exposed electrode (1, 4) and at least one insulated electrode (2, 3). A voltage source (6) is configured to generate an electrical field between the at least one air-exposed electrode (1, 4) and the at least one insulated electrode (2, 3, 70) to operatively generate a plasma proximal (100) to the plurality of electrodes and within the air-path conduit (15).

An electroacoustic transducer comprises a cathode having a plurality of cathode discharge elements in an array disposed around an axis associated with the cathode; an anode having a plurality of anode discharge elements in an array disposed around an axis associated with the anode; an inter-electrode space separating the cathode and the anode; and a current-limiting element configured to limit current supplied to at least one of the cathode or the anode when connected to the voltage source. The cathode discharge elements and anode discharge elements extend toward the inter-electrode space. The respective arrays of the cathode and anode are opposite of each other with respect to the inter-electrode space and are axisymmetric such that the cathode axis is aligned with the anode axis. At least one of the cathode and anode is configured to generate the acoustic signal when connected to a voltage source through the current-limiting element.

An electroacoustic transducer comprises a cathode having a plurality of cathode discharge elements in an array disposed around an axis associated with the cathode; an anode having a plurality of anode discharge elements in an array disposed around an axis associated with the anode; an inter-electrode space separating the cathode and the anode; and a current-limiting element configured to limit current supplied to at least one of the cathode or the anode when connected to the voltage source. The cathode discharge elements and anode discharge elements extend toward the inter-electrode space. The respective arrays of the cathode and anode are opposite of each other with respect to the inter-electrode space and are axisymmetric such that the cathode axis is aligned with the anode axis. At least one of the cathode and anode is configured to generate the acoustic signal when connected to a voltage source through the current-limiting element.

An improved effects device for use with audio sources is provided. The improved effects device includes a plasma speaker that receives an original electrical signal and emits both sound waves and a radio frequency signal derivative of the original electrical signal. The improved effects device also includes a radio receiver configured to receive the radio frequency signal and convert it into an electrical signal. The electrical signal may then be amplified and used to drive a conventional loudspeaker. Advantageously, the new electrical signal is altered from the original electrical signal. The improved effects device may also include a low gain amplifier that receives the original electrical signal from an audio source, like an electric guitar, and amplifies the original electrical signal before transmitting it to the plasma speaker.

Methods and apparatus to communicate via a welding arc are disclosed. An example welding-type power supply includes a power converter, a weld monitor, and an arc modulator. The power converter outputs welding power to sustain a welding-type arc at a welding-type torch. The weld monitor monitors one or more aspects of a weld performed using the welding-type arc and the welding-type torch, and selects an audio message based on the one or more aspects. The arc modulator configured to modify the welding-type arc to output the selected audio message as a plasma speaker.

An electroacoustic transducer may include a cathode having a plurality of discharge elements assembled into one or more axisymmetric arrays and an anode having a plurality of discharge elements assembled into one or more axisymmetric arrays. The cathode and the anode may be separated by an inter-electrode space and respectively connected to a voltage source. The discharge elements of the cathode and anode may be directed into the inter-electrode space. The axisymmetric arrays of the cathode and anode may be mirror symmetrically arranged opposite each other to form electrode pairs, each electrode pair having an axis of symmetry extending through the geometric centers of the axisymmetric arrays in the pair.

Recording, manipulating, distributing and creating sound pressure waves in one or more media by employing an apparatus that transfers the energy between photons and particles of the media is disclosed. An exemplary apparatus comprises one or more lasers and an isotropic or anisotropic medium for photon processing and distribution. An exemplary method comprises determining the target locations for sound pressure wave recording, manipulating or creation; transmitting photons to the target locations; transferring photon energy to media particles to create or manipulate a sound pressure wave; or transferring energy of media particles to photons for recording or manipulating a sound pressure wave.

A dynamic acoustic impedance matching device for an acoustic signal transmitted or received in a medium by a transducer includes a particle flow in an acoustic signal path of the transducer. The particle flow has an acoustic impedance between an acoustic impedance of the transducer and an acoustic impedance of the medium.

Methods and apparatus to communicate via a welding arc are disclosed. An example welding-type power supply includes a power converter, a weld monitor, and an arc modulator. The power converter outputs welding power to sustain a welding-type arc at a welding-type torch. The weld monitor monitors one or more aspects of a weld performed using the welding-type arc and the welding-type torch, and selects an audio message based on the one or more aspects. The arc modulator configured to modify the welding-type arc to output the selected audio message as a plasma speaker.