為何樂器同音符,不同聲音?

In the physics aspect, it is because the quality of sound produced by different musical instruments are not the same, though the frequencies are the same.

Musical instruments producing the same note (音符) give the same frequency of sound. But the wave forms they produce are not the same. These different wave forms are termed as "sound quality". Our ears are sensitive, not only to the frequency of sound, but also to the sound quality (wave form). This explains why we could distingush between sound produced by different musical insturments.

這個好簡單.
比如鋼琴,佢係用木鎚打擊音「玄」,所以佢係振動形式傳播聲音.
小提琴係用松香來摩擦玄,但係長,而唔係打擊,所以聲音又唔同.
長笛吹氣,內部會有聲波撞擊的情況,所以不停撞呀撞..就變得高音,卻不可以吹太低音.

總括而言,就係因為發聲的材料不同,而且令佢發聲的方式又唔同,所以發出的聲音也可一樣