ulträänihun
Ulträänihun is a Finnish term that translates to "ultrasound sound" or "ultrasound hum." It refers to the audible, often low-frequency sound that can be emitted by certain ultrasonic devices. While ultrasound frequencies are typically above the range of human hearing (generally considered to be above 20 kHz), some devices can produce secondary acoustic emissions or harmonics that fall within the audible spectrum. These audible byproducts are what is commonly referred to as ulträänihun.
The generation of ulträänihun can occur in various ultrasonic applications. For instance, high-power ultrasonic transducers used
For most individuals, ulträänihun is either inaudible or barely perceptible as a faint buzzing or humming noise.