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.
Acoustic energy is sound energy produced by vibrating objects. The definition of sound says that it is a disturbance of energy that comes through matter as a wave, and that humans perceive sound by the sense of hearing. Sound pressure is the effect and sound power (energy) is the cause. But our eardrums are only sensitive to the sound pressure, and so are microphone diaphragms.