Vibrations That Make Noise

Boom
Boom is a low frequency interior noise of 20-60 Hz. Sometimes the customers complain of a pressure in their ears. Examples of similar noises include a bowling ball rolling down an alley, deep thunder, or a bass

drum.
A customer may use the following words to describe boom:
- Droning
- Growling
- Moaning
- Roaring
- Rumbling
- Humming

Boom may be accompanied by a perceptible vibration (roughness).

Moan or Drone
Moan or drone is a sustained tone at a low frequency of 60-120 Hz,somewhat higher than boom.
Examples of similar noises include a bumble bee or blowing air across the top of a soda bottle. A customer may use the following words to describe moan or drone:
- Humming
- Buzzing
- Resonance
Moan or drone may be accompanied by a perceptible buzzing vibration. Inspect the following systems:
- The powertrain mounts
- The exhaust system

Howl
Howl is a noise at mid-range frequency of 120-300 Hz. This sounds like the wind howling.

Whine
Whine is a prolonged, high-pitched sound in the 300-500 Hz range. Whine is usually related to the meshing gears or gear noise. Similar sounds include mosquitoes, turbine engines, and vacuum cleaners.