How do heavy metal artists/bands make their voice so deep?

Amplitude is: a. the number of waves in a certain amount of time. b. the distance between the top or bottom of a wave and the center of the wave. c. the noise floor acceptable in recording. d. the distance between two identical points on a wave.

The ishtar gate can be seen in its reconstruction state in the plz

Escribe un adjetivo a cada sustantivomelodiosas - claro - mole. stos - oscura - espaciosos - bulliciosas - tranquilo - acogedora - día - noche - músicas - ruidos - casa - pueblo - pisos - ciudades