ELi5: What actually causes vibrato when singing?
In: Biology
Vibrato is a style/quality of singing, and it’s something you consciously choose to do, so I don’t know that I’d phrase it as “causes vibrato”, but to add vibrato to a note being sung you simply slightly tighten and loosen your vocal chords to fluctuate the note being sung so it’s not just a constant flat note.
In the same way you would add vibrato to a violin or cello note by slightly moving your finger to shorten and lengthen the string to change the pitch a slight amount to the same effect.
Vibrato is just like it sounds, a vibration! By vibrating whatever mechanism is responsible for determining the pitch of a note, we can create a controlled oscillation around our desired note (think of a sin wave that goes around a line on a simple graph).
We can do this on many instruments! For guitars and violins we use our fretting/fingerboard fingers to control pitch, so by quickly bending the string in a vibration motion we can achieve vibrato. This same concept carries over to our bodies when singing—even whistling! The only difference is that instead of pitch being decided by string length/tension on where we place our fingers, it’s decided by tension of our vocal muscles!
It takes practice, but by relaxing the throat muscles and providing a steady airflow using the diaphragm, our vocal folds naturally vibrate and produce vibrato. Unlike with string instruments where we have to actively create vibrations, vibrato in our voice is actually the natural state that occurs when our muscles are relaxed. It’s not so much that we create vibrato with our voice, but that we stop suppressing it by our tightened muscles!
This is the correct and healthy way to achieve vibrato with your voice, but you can often hear people using improper techniques to achieve a “fake” vibrato. If you have the mindset like string instruments where you actively need to produce a vibration, you might try to stagnate airflow, or shaking their jaw. You can still create a similar oscillation vibrato effect, but most people would agree it sounds unnatural or amateurish. I just thought I’d mention this point to add further context that there are multiple ways to achieve the same effect, but they’re mostly considered improper techniques that have less ear-pleasing results.
I teach voice. There is “natural” vibrato and “forced” vibrato.
Natural vibrato is a slight 1/4-1/2 step fluctuation in pitch above the sung note, cycling about 6 times per second give or take, and occurs when you hit a sweet spot of vocal cord tension vs airflow, which is heard in well-trained voices.
Forced vibrato is when someone produces a similar sound consciously. There are several ways people do this, either by “pulsing” the air to approximate true vibrato (like Stevie Nicks does, which can sound like the bleating of a goat), moving their jaw up and down (although Whitney Houston was a fantastic singer, she relied on this technique), consciously altering the pitch (and if the singer does this to a lower quarter or half-step it sounds “wobbly”), or a combination of these. These methods don’t sound as good as true vibrato, they can be too fast or slow, and sound uneven. They’re also bad for the voice, creating unnecessary tension, tiring out the muscles, and leading to bad vocal production habits which can be very harmful to the health of the vocal cords.
Hope this helps.
Edit: spelling errors.
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