Formants In Singing – What on earth are they?

So, let’s talk about Formants in Singing…

While I’ve taken a break from coaching and working on my own voice in general over the Christmas holiday (boy was that a good rest!), I’ve been doing quite a bit of reading on formants in singing. If any of you have any interest in voice science, I can thoroughly recommend Kenneth W. Bozeman’s ‘Practical Vocal Acoustics’. This is a helpful book covering the science of the voice from the perspective of the TEACHER and the singer, rather than purely from a voice scientist’s perspective. It’s this book that I’ll be drawing on for today’s explanation.

One of the things that keeps cropping up in my ol’ noggin is how critical the first bridge is… why? Because it’s crossing this portion of the voice that enables access to the rest of the voice… therefore, pretty important!

For many of us, we may accept that there IS this magical mysterious thing called a “bridge” or “passagi”, or as Kenneth W. Bozeman puts it, “where the voice turns over”… but…

What exactly is the first bridge?

Let’s discuss this. To do that we need to do a very quick (and very coarse) anatomy lesson.

The voice as an instrument consists of two parts:

1) the vocal cords; and

2) the vocal tract (the airway tube between your vocal cords and your lips)

The vocal cords

The vocal cords generate sound (acting as a source of sound), the vocal tract shapes the sound (filter). From here on in, please do me a favour – think of the vocal tract like a plastic water bottle, the squishable kind you can buy from any corner store.

The vocal tract

Have you ever blown across the top of a bottle that isn’t completely full? Have you ever noticed that the bottle has a particular pitch that it seems to generate? This is called resonance. Empty volumes (like plastic bottles) have distinct frequencies that they vibrate at when excited (e.g. by blowing across the top of it). You can spot the same effect by banging the side of a long cardboard poster tube and notice the pitch of the noise it emits, or even by humming down the length of that tube. These pitches are referred to as “formants”, and are a by-product of the fact that empty volumes exhibit resonance at particular frequencies.

NOTE: You don’t need to remember all this per se, I merely mention it so you respect the idea that empty volumes have an associated pitch they like to vibrate it, and that these pitches are called formants.

Now, let’s continue the analogy. If you change the shape of the empty volume inside the bottle (e.g. by squeezing it or adding some water in/taking some water out), then blowing across it, the associated pitches it wants to vibrate it (the formants) will have changed. The same effect can be achieved by cutting that long cardboard poster tube to a different length, then banging it again. The change in shape affects the resonance, which in turn affects the formants.

HALFWAY SUMMARY:
– The vocal cords generate specific frequencies (the singer’s pitch)
– The vocal tract resonates at specific frequencies (the formant(s) of the instrument)

In short, despite the chief difference where the cords generate the frequencies whilst the tract doesn’t actually generate those frequencies, both the vocal cords and the vocal tract possess their own particular sets of frequencies that are associated with them.

It’s the interaction between these two sets of specific frequencies that is an important phenomenon for singing.

Here’s the low-down…

The first bridge occurs when a certain frequency generated by the vocal cords happens to pass through a certain corresponding frequency of the vocal tract (a specific formant)*.

As you can see, this makes the whole concept of the first bridge *relatively* straight-forward to understand, but also results in the realisation that it’s a REEEEEEALLY complicated thing to get sorted in singers. If the first bridge happens as two frequencies cross each other, then what happens if they both start changing together? What happens if one suddenly changes during the process?

It’s a complicated system… it’s dependent on the pitch/frequency of the voice, the pitch that the vocal tract wants to vibrate it, which in turn is dependent on the shape of the vocal tract, but is also affected by the volume of the singer (as this affects excitation of the vocal tract).

*Deep breath*

Don’t panic.

This is all completely trainable, and completely manageable… but it takes more than just good exercises. It requires (in my opinion) a structured and logical approach to applying those exercises, so that singers are not constantly hyper-aware of bridges and essentially trying to control a million things at once all whilst trying to sing with emotion, but instead builds the required co-ordination into muscle memory, to thereby make easy connected singing automatic.

So… now you know where the first bridge comes from… What’s stopping you?

* – Specifically, when the second harmonic (H2) generated by the vocal cords passes through the first formant (F1) of the vocal tract. You DON’T need to remember this to be a great singer.