Classically Savvy

Think for a moment about the phrase “out of tune”. Take a moment to get a clear mental picture of what that term means to you. Hear it in your ear. It’s unpleasant, right?

The classic example is the elementary school band or orchestra concert. Even if all the students play the right notes, it’s rarely a pretty sound. Partly, that’s due to lack of refinement of technique. They’re trying so hard just to play the notes, that they’re not able to listen to the people around them and adjust.

When musicians are in tune, their tones blend, and it sounds clear. An example: at the Basilica of St Mary, there’s always a Gregorian chant to start the liturgy; the cantor stands behind the high altar and is virtually invisible. Last Sunday, two soprani did the chant together. People in the congregation were surprised to find out after Mass that there were two singers — the musicians were so well in tune that it sounded like one strong voice.

Why?

Waves are additive. Two sounds are added together to form a single complex sound wave. When two tones are exactly in tune (i.e., they have the exact same frequency, measured in Hertz or cycles per second), they are “in phase.” Add them together, and you get a single, louder sound.Look at the example below. Notice the two tones at the top (both 437 Hertz) appear to be about 3/4 inches tall on your screen. Then, look at what happens when both are sounding together — the resulting wave is still 437 Hz, but it’s about 1 1/2 inches tall. In other words, because the pitches were in tune, their amplitudes added together (3/4 + 3/4 = 1 1/2). The result? More volume.

To hear this, click the image to go to Thinkquest. Listen to Frequency 1, Frequency 2, and then the combined wave.

But what would happen if the pitches are not in tune?

Since their frequencies are not the same, they cycle between being in phase and out of phase.

Here’s an everyday example. You’re sitting in the left turn lane with your signal on. The car in front of you has their signal on. As you watch the two signals blink on-off-on-off, eventually, your blinkers and the car in front of you will match up for a second or two. Wait another few seconds, and your blinkers will be off while theirs are on. A few more seconds, and they’ll blink together again. This pattern would continue all day, or at least until the light changes and you both go on your merry ways.

If pitches are not in tune, there’s interference; they’re not in phase, the acoustic version of two blinkers out of sync. This leads to a “wah-wah-wah” sound that’s known as a beat.

Acoustic beats
To hear it, go back to Thinkquest. Set the two frequencies to different numbers. You’ll barely notice the difference in the pitches when you hear them alone, but you’ll both see and hear the beats in the combined wave!

The easiest way for musicians to be in tune is to listen for beats, and adjust. Sometimes you can’t tell if you’re high or low, so you have to guess. You try bringing down the pitch, but start to hear more beats. OOPS! That meant you were already low to begin with, and have gone even lower. So then, you raise the pitch, the beats get slower and slower, and eventually, you’re right in tune with the other musicians.

Listen carefully the next time there’s a unison passage (i.e., everyone is singing/playing the same pitches without harmony). If you’re really listening, you’ll hear beats in the sound from time to time.

A parting thought: No ensemble is has perfect intonation, but the better the ensemble, the quicker they adjust.