US Patent 11706552 Open audio device

An open audio device including an acoustic radiator that emits front-side acoustic radiation from its front side, and emits rear-side acoustic radiation from its rear side. A front acoustic cavity receives front-side acoustic radiation and comprises at least one front sound-emitting opening, and a rear acoustic cavity receives rear-side acoustic radiation and comprises at least one rear sound-emitting opening. The front and rear acoustic cavities each have a fundamental frequency. The fundamental frequencies are within one octave of each other.