A thermo-electro-acoustic engine, comprising: a generally hollow body having first and second open ends, said body containing a working gas; a regenerator disposed within said body; a first heat exchanger disposed within said body and abutting said regenerator at a first longitudinal end thereof; a second heat exchanger disposed within said body and abutting said regenerator at a second longitudinal end thereof; a third heat exchanger disposed within said body and between said second heat exchanger and said acoustic energy converter; an acoustic source coupled to said first end of said body such that acoustic energy from said acoustic source is directed into said body; an acoustic energy converter coupled to said second end of said body opposite said first end relative to said regenerator such that at least a portion of acoustic energy within said body is directed to said converter and converted thereby into electrical energy; said converter electrically coupled to said acoustic source such that at least a portion of electrical energy produced by said converter is provided to and drives said acoustic source; output terminals (c, d) electrically coupled to said converter such that at least a portion of electrical energy produced by said converter is provided to said output terminals for utilization external to said engine; a combiner disposed between and in electrical communication with said converter and said acoustic source, and; a tunable electric network comprising: impedance circuitry disposed between and in electrical communication with said converter and said combiner such that electrical energy provided by said converter is coupled to said acoustic source via said combiner, and a phase delay device (φ(ω)) disposed between and in electrical communication said converter and said combiner such that the frequency and phase of the electrical energy produced by said converter can be controlled for frequency and phase locking to an external input signal (e, f) provided to the combiner, to control the frequency and phase of an acoustic wave operating within said thermo-electro-acoustic engine. a generally hollow body having first and second open ends, said body containing a working gas; a regenerator disposed within said body; a first heat exchanger disposed within said body and abutting said regenerator at a first longitudinal end thereof; a second heat exchanger disposed within said body and abutting said regenerator at a second longitudinal end thereof; a third heat exchanger disposed within said body and between said second heat exchanger and said acoustic energy converter; an acoustic source coupled to said first end of said body such that acoustic energy from said acoustic source is directed into said body; an acoustic energy converter coupled to said second end of said body opposite said first end relative to said regenerator such that at least a portion of acoustic energy within said body is directed to said converter and converted thereby into electrical energy; said converter electrically coupled to said acoustic source such that at least a portion of electrical energy produced by said converter is provided to and drives said acoustic source; output terminals (c, d) electrically coupled to said converter such that at least a portion of electrical energy produced by said converter is provided to said output terminals for utilization external to said engine; a combiner disposed between and in electrical communication with said converter and said acoustic source, and; a tunable electric network comprising: impedance circuitry disposed between and in electrical communication with said converter and said combiner such that electrical energy provided by said converter is coupled to said acoustic source via said combiner, and a phase delay device (φ(ω)) disposed between and in electrical communication said converter and said combiner such that the frequency and phase of the electrical energy produced by said converter can be controlled for frequency and phase locking to an external input signal (e, f) provided to the combiner, to control the frequency and phase of an acoustic wave operating within said thermo-electro-acoustic engine. impedance circuitry disposed between and in electrical communication with said converter and said combiner such that electrical energy provided by said converter is coupled to said acoustic source via said combiner, and a phase delay device (φ(ω)) disposed between and in electrical communication said converter and said combiner such that the frequency and phase of the electrical energy produced by said converter can be controlled for frequency and phase locking to an external input signal (e, f) provided to the combiner, to control the frequency and phase of an acoustic wave operating within said thermo-electro-acoustic engine.