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.
In physics, sound is a vibration that propagates as a typically audible mechanical wave of pressure and displacement, through a transmission medium such as air or water. In physiology and psychology, sound is the reception of such waves and their perception by the brain. Humans can hear sound waves with frequencies between about 20 Hz and 20 kHz. Sound above 20 kHz is ultrasound and below 20 Hz is infrasound.