I learned a very curious thing after going to the Listening Centre in Toronto some years ago: there is a subtle yet profound difference in how the left and right ear actively process sound. Are audiologists aware of this and what it means for musicians?

Let's assume for the sake of argument that you have great hearing. You've been tested by an audiologist and your hearing- at least on paper- is excellent. In fact, your ears look identical on the graph. Does this mean that your left and right ear process sound in the same way when you vocalize or play an instrument? No. It doesn't.

When you have a hearing test you aren't making a sound. You aren't being active, that is, vocalizing in any way. You aren't talking, singing, sighing or crying. The sound is coming in, not going out. And this can be measured on a graph. But what happens when you make a sound? Is there a difference between the two ears? Yes. There is. It's not one, however, that can be measured on a graph, though it can be perceived, which is where science and art diverge. A simple exercise will show you what I am talking about.

Right vs Left Ear Exercise

1. Hold your right hand, palm facing you, up to your mouth. Hold it no more than two inches away. Your little finger will be in line with your nose. Now speak or sing slowly in a resonant voice into the heel of your hand. Listen to the quality of the tone.

2. Hold your left hand, palm facing you, up to your mouth. Hold it no more than two inches away. Your little finger will be in line with your nose. Now speak or sing slowly in a resonant voice into the heel of your hand. Listen to the quality of the tone.

3. Repeat steps one and two at least three times. Write down your impressions. Experiment by slowly and resonantly intoning the 5 Italian vowels, or recite poetry and bits of verse from memory.

Is the quality of the tone the same on the right side as on the left? While you may not put your finger on it immediately, you probably noticed a qualitative difference between the ears. This difference is - for singers anyway - precious knowledge.

For those with excellent listening ability, the right side will sound higher and brighter, while the left side lower and darker. The left side can also seem closer, while the right farther away. In contrast to each other, the left hand seems to be missing something, while the right hand seems to be full of sound from top to bottom. This is because the right ear, according to Tomatis, actively processes higher frequencies faster. They are much more stimulating than lower ones, and have a huge impact on the voice and the acquisition of beautiful chiaroscuro tone. To paraphrase Duke Ellington: It don't mean a thing if it ain't got that ring. And the singer's awareness of the tonal quality on the right side needs to lead the left, which enables the singer to establish true ring in the voice.

I've been onstage with quite few of singers who use the left ear to lead the voice (the trained observer can see as well as hear the difference). While the sound is often big, the voice doesn't touch (a vestibular part of listening) the listener in the same way as that of the right-eared singer. The left-sided singer sounds distant, as though coming from another room. Of course, this isn't limited to singers. I've also worked with a well-known conductor, a highly intelligent man, who gets frustrated because he isn't being followed properly. However, it's clear to the trained eye that the gentleman leads with his left ear and is behind his own beat.

How we process sound matters. It has everything to do with how we communicate with ourselves and others. For those with listening problems, the right ear can be awakened. While this would involve a full course of listening training with a skilled practitioner, the exercise above can be useful. I ask my own students who have difficulty obtaining a clear free tone to practice reading to themselves for 20 minutes a day with the right hand held close to the mouth as though holding a microphone. Though it is a pun it is no less true: this exercise can help make everything right.