Every instrument has a resonator, and few resonators are more famous (or less known) than the soundboard of a Steinway concert grand. Part No. 81, as they call it in the Steinway factory, gives each instrument its unique and world-coveted sound. James Barron describes it in Piano: The Making of a Steinway Concert Grand:
Part No. 81 is a sheet of glued-together wood thinner than the ubiquitous four-by-eight sheets of plywood that weekend woodworkers jam into their sport utility vehicles on Saturday mornings…it is the largest single piece of wood in the piano….It will function as the piano’s amplification system, a preelectronic triumph of physics. Without help from a single audio cable or input jack, it will transform relatively weak vibrations of the strings into sounds powerful enough to fill a concert hall.
A much more ancient triumph of physics is the voice’s resonator, but what is that, exactly?
“Resonance” is one of those discussions in singing that gets just as much confusion as discussions of the diaphragm in breath support. It’s that elusive, hard-to-pinpoint thing that seems to straddle the boundary between physics and fairy tale. Some people say that the sinuses “resonate” when you’re in your head voice, and the trachea and sternum “resonate” in chest voice. Others speak of the larynx, pharynx and mouth as resonators, which is more physically accurate, but then how do you explain the other buzzy sensations in your head that accompany the “resonant” sound you’re listening for?
When I talk about resonance, I split the difference between pure physics and metaphor and compare the voice to a Steinway grand. The vocal cords correspond to the strings of the piano, which would not be amplified if it weren’t for a carefully crafted soundboard. And the soundboard of the singer is the hard palette, the roof of the mouth. I have students hum with their jaw gently separated, as if they were tasting something delicious, to access the resonance of the hard palette.
Singing originates in the larynx with the vibration of the vocal cords; from there, the sound travels up through the pharynx and hits the roof of the mouth before exiting. Vocal sound does not travel up into the sinuses or down into the chest; it cannot begin below the larynx or come out of any part of the head except the mouth. It would be just as useless to say that the sound of a saxophone comes out anywhere but the bell of the instrument.
When a singer feels buzzy sensations in the head or chest that feel like “resonance,” that’s called sympathetic vibration. Singers often monitor these sensations to make sure that their sound is free and open in all the right places. When they actively direct where and how the vibrations are felt, that’s called placement. You can gather a lot of good data about your voice when you work this way, but the pitfall here is when you confuse the vibratory sensation with the resonating sound itself. The two are not the same!
So I always try to be careful when using the word resonance; I always say when I’m using the word acoustically or metaphorically. If I’m speaking acoustically, I’ll talk about the hard palette and the vocal tract doing the work, with the lungs supplying the breath and so on. If I’m speaking metaphorically, I talk about the resonance of “the whole instrument,” which for me extends from the base of the pelvis to the top of the head and beyond, with sound coming out everywhere. But I make sure to say I’m not speaking literally!
It’s always good to remind yourself of what actually is resonating in the acoustic sense – what your voice’s sounding board is – and then distinguish all other vibrations from there. Then you can have all those elements working for you, however you perceive them, physically or metaphysically.