Noise and Vibration Control in Automotive Bodies

7Door Closing Sound Quality

7.1 Vehicle Sound Quality

7.1.1 Concept of Sound Quality

We live in a world filled with all kinds of sounds. People enjoy sweet sounds, such as a warble, and hate noise, such as airplane booming or noise at construction sites. People usually use special words to describe the sounds: love or hate, enjoy or dislike, prefer or ignore, etc. Their sensations on the sounds have no direct interrelation to the sound loudness; instead, they are strongly related with their subjective perception, which introduces a “quality” concept of the sounds.

Quality is a feature of an object that is different from other objects. Sound is the reception of audible mechanical waves and their perception by the brain, i.e. the human auditory impression. “Sound quality” is the combination of “sound” and “quality,” that is, the unique sensations of hearings. Sound quality is typically an assessment of the accuracy, enjoyability, or intelligibility of the sound.

According to its definition, sound quality reflects human subjective sensations. Even for the same sound, each person’s feelings might differ. Figure 7.1 shows the cartoon pictures of a violin and a tractor. Most people love melodious music from the violin but dislike the irritable and booming noise from the tractor. Do all the people dislike the noise of the tractor? No. During planting and harvesting seasons, farmers drive their tractors in the fields, and the roar of the tractors brings joy and excitement to many ...