Harmonics

As we grow, most often, we don’t question why things happen the way it happens. In contrast, when we are very young, we tend to ask too many questions and tend to explore a lot. I guess, as we grow, we take things at its face value rather than questioning them.

The sound is nothing but vibrations composed of frequencies. When you pluck a string in guitar, it produces vibrations of the air molecules and our ear senses it as music. Have you ever wondered why Veena sounds different than Guitar even when playing the same note for the same length of time at the same loudness?

The theoretical explanation is that “Timbre” of the instrument makes it different. So, what is the “Timbre”? By definition, “Timbre” is the color of the sound. Like how, Yellow looks different than Blue, the sound quality and color is determined by Timbre. This helps to explain our problem at the 20,000 feet level and to get through the exam. Want to further deep dive? Read on..

Take a String of a particular length and pluck the string in the middle. You will hear a sound at a particular frequency (say) f. This frequency is called “fundamental frequency”.

Now, reduce the length of the String by half and pluck the string again. Now, you will hear a sound at a higher frequency. (To be precise, the frequency will be doubled – 2f). If reduce the length of the String by one-third, the frequency will triple – 3f. Theoretically, if you consider the String as two segments, each segment vibrates at twice the fundamental frequency. If you consider the String consisting of 3 segments, then, each segment vibrates at thrice the fundamental frequency. And so on..

Hence, theoretically, there are infinite frequencies consisting that are multiples of fundamental frequencies (i.e.) 2f, 3f, 4f, 5f and so on. These frequencies are called harmonics. So, each note from any instrument is a complex wave containing more than one frequency.

Timbre of the instrument is mainly determined by this harmonics and other dynamic characteristics of sound like attack-decay envelope of the sound. This Timbre makes oboe sound different than (say) flute.

Rest in next.