Major players in the drama of 19th-century Texas were definitely the Comanches who at this time swept down from the cool highlands of the southern Rockies, and, mounted on horses, drove other tribes from West Texas.
What is SOUND? The periodic mechanical vibrations and waves in gases, liquids and solid elastic media. Specifically the sensation felt when the eardrum is acted upon by air vibrations within a limited frequency range, ie 20 Hz to 20 kHz. Sound of a frequency below 20 Hz is called infra. STRUCTURE-BORNE SOUND.
Audible Sound. Usually sound is used to mean sound which can be perceived by the human ear, i.e., sound refers to audible sound unless otherwise classified. A reasonably standard definition of audible sound is that it is a pressure wave with frequency between 20 Hz and 20,000 Hz and with an intensity above the standard threshold of hearing.