Wed February 16, 2011 By: Siddharth Poonia

what makes sound annoying or pleasent? plz define pitch more detailed.?

Expert Reply
Thu February 17, 2011
Dear student
Noise can be defined as an irregular succession of disturbances, which are discordant and unpleasant to the ear.
When two waves with different frequencies reach the ear, the resulting sound will be pleasant if the frequencies have ratios that are small whole numbers (2:1, 3:2, 4:3). This is called consonance.
On the other hand, an unpleasant sound or noise will be produced if the frequencies have ratios others than small whole numbers. This is called dissonance.

Although for most practical purposes, the pitch of a sound can be said to be simply a measure of its frequency, there are circumstances in which a constant frequency sound can be perceived to be changing in pitch.

One of most consistently observed "psychoacoustic" effects is that a sustained high frequency sound (>2kHz) which is increased steadily in intensity will be perceived to be rising in pitch, whereas a low frequency sound (<2kHz) will be perceived to be dropping in pitch.

The perception of the pitch of short pulses differs from that of sustained sounds of the same measured frequency. If a short pulse of a pure tone is decaying in amplitude, it will be perceived to be higher in pitch than an identical pulse which has steady amplitude. Interfering tones or noise can cause an apparent pitch shift.

We hope that clarifies your doubt.




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