sound speed

supersonic speed (exceeds speed of sound / Mach 1)

sound ranging (artillery sound ranging)

local speed of sound

variable-speed with speed control

instantaneous vertical speed indicator / instantaneous vertical-speed indicator (IVSI)

Nr gauge (Nr = speed of rotation) / rotor speed sensor

Motor PWM speed separated from PID speed

clicking sound

communications by sound

high-intensity sound

sonar (sound navigation and ranging)

sound communication

sound wave

sound-absorbent tile

stun grenade / flash grenade / flashbang / thunderflash / sound bomb

artillery sound reconnaissance

sound damping

aerial sound ranging

air registration point (in sound ranging)

high-frequency sound waves

sound-proof compartment

background sound pressure level

overall sound pressure level

adjusted slope of sound pressure level

atmospheric sound absorption

change in slope of sound pressure level

slope of sound pressure level

aircraft sound proofing

average slope of sound pressure level

final background sound pressure level

heat insulation-sound proofing

precision sound level meter