The production of audible sound from modulated ultrasound without the need of an active receiver is referred to as “sound from ultrasound” in this context. This occurs when the modulated ultrasound passes through a nonlinear medium that functions as a demodulator, either consciously or unconsciously.
At 100 to 110 dBSPL, a transducer can be produced to emit a focused narrow beam of modulated ultrasound that is strong enough to significantly alter the sound speed of the air it passes through. The sound is only audible along the path of the beam or appears to radiate from any surface the beam impacts because the air within the beam exhibits nonlinear behavior and extracts the modulation signal from the ultrasound. With the use of this technique, a sound beam can be transmitted over a large area while only being audible in a small, clearly defined area; for listeners beyond the beam, the sound pressure significantly lowers.
How do I get sound from my speakers to my projector?
- Position the speakers where you want them, and plug them into power or insert the batteries.
- Connect an audio cable to one of the audio output options on your projector.
- Connect the other end of the cable to your speakers. …
- Adjust the volume on your projector.