intensity

(noun) the amount of energy transmitted (as by acoustic or electromagnetic radiation). Synonyms: strength, intensity level. Examples: "He adjusted the intensity of the sound." "They measured the station's signal strength."

(noun) high level or degree; the property of being intense. Synonyms: intensiveness.

(noun) the magnitude of sound (usually in a specified direction). Synonyms: volume, loudness. Example: "The kids played their music at full volume."

(noun) chromatic purity: freedom from dilution with white and hence vivid in hue. Synonyms: saturation, chroma, vividness.