You can also produce UHF sound with hardware other than the speaker. For instance, you can overdrive caps in various systems - most commonly LCD display drivers

You can also produce UHF sound with hardware other than the speaker. For instance, you can overdrive caps in various systems - most commonly LCD display drivers - and make them squeak in the audible or inaudible range. Can’t find much out there on the topic, but here’s a Reddit thread touching on it: https://www.reddit.com/r/InternetIsBeautiful/comments/2ruq45/on_some_lcd_monitors_this_page_will_cause_the/ https://www.reddit.com/r/InternetIsBeautiful/comments/2ruq45...