# Acoustics/Interior Sound Transmission

## Introduction to NVH

Noise is characterized by frequency (20--20 kHz), level (dB) and
quality. Noise may be undesirable in some cases, i.e. road NVH yet may
be desirable in other cases, i.e. powerful sounding engine.

Vibration is defined as the motion sensed by the body, mainly in
0.5 Hz - 50 Hz range. It is characterized by frequency, level and
direction.

Harshness is defined as rough, grating or discordant sensation.

Sound quality is defined according to Oxford English Dictionary, \"That
distinctive Quality of a Sound other than it\'s Pitch or Loudness\"

In generally, ground vehicle NVH and sound quality design are attributed
by the following categories:

1.) Powertrain NVH and SQ: Interior Idle NVH, Acceleration NVH,
Deceleration NVH, Cruising NVH, Sound Quality Character, Diesel
Combusition Noise, Engine Start-Up/Shut-Down

2.) Wind Noise: Motorway Speed Wind Noise (80-130kph), High Speed Wind
Noise (\>130kph), Open Glazing Wind Noise

3.) Road NVH: Road Noise, Road Vibration, Impact Noise

4.) Operational Sound Quality: Closure Open/Shut Sound Quality, Customer
Operated Feature Sound Quality, Audible Warning Sounds

5.) Squeaks and Rattles

**== Noise generation ==**

## Structural vibration response

## Structural acoustic response

## Sound propagation

## Applications to vehicle interior sound transmission

## Useful websites

## References

