Alarm sound intensity (volume) varies according to the amplitude of the acoustic wave, the larger the amplitude, the greater the sound. If the piano pronunciation body in the projectile intensity and the small situation, the sound size is different, this size different difference, called the tone intensity, its unit uses the physical quantity-db.
The volume range that we can accept is about 10 million times times the rate of the faint sound and the large sound that feels painful. Such a large ratio of figures, expressed in absolute units, is very inconvenient. In addition to the sense of sound, not like the size of the ruler of the same interval, but with the ratio of change, so use compared to the original large several times, or a few a of the method is more consistent with our feelings, to use the unit is DB. A decibel is not an absolute unit, but a ratio between a standard and a measured quantity.
Timbre is determined by the high frequency composition (octave, Gao Pingpo, harmonics) of the sound and the instantaneous change in volume. Even if the tone of the intensity and tone of the same timbre can be different, such as the sound of the piano and the portable harp, the voice of different people, birds and tigers of the sound of different causes is also different from the timbre.
Sunlight through the prism, divided into colorful color, you can see that the sun is composed of a variety of colors (that is, a variety of vibration number) of the light synthesis. The composition of the sound is similar to that of the sun. Each sine wave can be regarded as a sound material, and the different combinations of these sine waves can produce different timbre.
The alarm has many kinds, its alarm sound also has many kinds, chooses a good alarm the main or its alarm sound is not enough penetrating dint, can warn the people, warns the unwitting person not to accidentally tread into the dangerous lot.