The Physical Feeling of Sounds
I’ve been playing music seriously now for about four years and it still suprises me how every few months a new dimension opens in my perception.
At first I was content to simply play the right notes in a chord to some kind of tempo. After that came microtiming, timbre, attack, degree of legato, the level of stress in chords and intervals, anticipation and suprise in rhythmic phrases, the hemiola. The list of musical features goes on and on.
Today I want to reflect on a the physical feeling one gets when hearing or producing sounds. We all know that there are many notes to choose from and that there are overtones of each note at multiples of the fundamental frequency. Recently I’ve started noticing that certain overtones seem to stimulate certain areas of the physical body, especially when sung, and that these areas might have emotional effects.
For example one day I was watching Rage Against the Machine at a concert and I was struck (literally) by a pounding feeling in my chest every time the kick drum went off. It seemed that the sound of the kick drum was somehow linked to the resonant frequency of my chest cavity, and perhaps this is the function of the kick drum - so that when the kick fires it is playing not only the air at 30-60Hz, but also playing the chests and hearts of everyone in range. Consider this then, that vibrations in this 30-60Hz band map to a physical space in the lungs or chest.
On the opposite end I was mixing some vocal tracks and noticed an unpleasant nasal quality to some vowels which could be removed by adding a band stop filter around 2kHz. (Or by singing slightly differently). So perhaps the nasal resonance is near this frequency and produces an attention-getting, but slightly annoying quality. Think of Axel Rose singing “Sweet Child of Mine” - you’ll definitely notice him, but I dont think it would lull anyone to sleep.
It is possible to think of the human vocal tract as a vibrating string with low tones low in the torso and higher tones in the throat or head. Higher pitches require higher levels of tension to produce and probably result in higher tension in the listener. I wonder if we could show some other physiologial effects by considering vibrations at different frequencies.
Here’s a rough map of frequency to body position:
- C3 (131Hz) - deep chest
- C4 (262Hz) - middle of the throat
- F#4 - this is the natural tension-free note for my voice
- C5 (524Hz) - back of nasal passages
- C6 (1.04kHz) - top of the nose
Questions:
- What is the natural frequency of the chest cavity or heart?
- If the deep chest sounds stop at 100Hz or so, what areas of the body are stimulated by deep bass (30Hz)?