Some thoughts on hearing

More ear problems

This week it turned out that although I may have had catarrh, my ear is definitely blocked on the outside too. So I’m going to make an appointment as soon as possible to have it syringed.

The blockage got worse early last week, so on Thursday I found myself at a rehearsal with a left ear which was significantly more deaf than it had been for the concert which I recently described. I’m writing about it because although it was extremely unhelpful for playing, I found the reasons for its being unhelpful quite interesting. They’re suggestive about the way hearing works in an orchestra.

The difficulty

Of course, as at that concert, it was hard to judge my playing volume. That’s not at all surprising. But also, it was much more difficult to play in tune, which led to some thoughts about how I normally do this.

Obviously if you can’t hear another instrument you can’t play yours in tune with it. But that wasn’t the difficulty; I could hear the other instruments, but couldn’t easily make the fine adjustments needed to home in on the required pitch to blend with them. I’m not sure whether the problem was that I was hearing my violin from a distance, out of the “wrong” ear, or whether it goes further and the lack of binaural hearing was the obstacle.

I don’t believe that merely hearing how far your pitch goes up or down will guarantee that you’re in tune with other instruments. For one thing, for mathematical reasons, the required pitch of a note can vary according to context, and there’s a continual conflict between the pitches which provide smooth melodies and those which provide clean harmony. (The theoretical difference can be quite large: a fifth of a semitone or even more.)

How do you tune your instrument at the start of the rehearsal? Ideally, like this: the oboe plays an A; you play an A on your instrument, quietly enough to hear the oboe you’re tuning to, and you adjust the pitch until the sound of your instrument blends in with that of the oboe.

Hearing, blending and intonation

If two notes which are nearly but not quite in tune with each other are played together, one hears beats: pulsations in the volume of the sound. This is because the sound waves from the two instruments get in and out of synch with each other. When they’re in synch, the sound is louder; when they’re out of synch, they cancel out and the sound is quieter. The more nearly in tune the two are, the slower the beats; when they’re completely in tune, the beats disappear.

What I mean by “blending with the oboe” is that you can’t hear any beats between your instrument and the oboe. Furthermore, at least with a violin, if you play it very quietly, you can no longer tell which is you and which is the oboe; your sound disappears into that of the oboe.

On tuning at the start of the rehearsal, it was clear that I couldn’t judge this blending very easily. I had, however, tuned carefully to an electronic tuner which indicates the pitch visually. Why couldn’t I hear it? Partly, I think, because I could hear everyone else tuning just as loudly as myself; but maybe also because of another phenomenon I’ve noticed, also to do with beats.

It’s well known in acoustics that if two pure notes are played simultaneously, a third one can be heard along with the other two. For example, an A at 440 Hz played with an E at 660 Hz will produce an A an octave down, at 220 Hz. Its frequency is the difference between the two being played, and it’s the result of the beats I was talking about earlier. They simply happen fast enough to become a musical note themselves.

When playing two notes at once (unaccompanied) on a violin, I can normally hear these “difference notes” surprisingly loudly. Some people have trouble hearing them at all; I think that’s probably because they’re listening in the wrong place. I realised this several years ago. The third note doesn’t sound as though it’s coming from the violin. It sounds as though it’s coming from just inside the ear. Which is, in fact, where it’s generated. And I experience a feeling of actual vibration in the ear. That’s where you have to listen for it.

How do you tell whether your tuning is blending with the other instruments around you? Again, it seems to me, by hearing beats, though you might not be conscious that that’s what you’re doing. The feeling of shrill dissonance when a note is horribly out of tune is actually the feeling of hearing beats at a particularly unpleasant speed.

I think what was missing, with my blocked ear, was the sense of sounds interacting in my ear. Instead of feeling pressure vibrations, I simply have a sensation of slight pressure from the blockage.

So my scientifically untested hypothesis is that playing in tune in an orchestra depends not just on hearing pitches from a distance, but also on the physical sensations occurring in the ear as the different sounds arrive and interact.

And I might not have realised that without a blocked ear! But now I’ve realised, I’m looking forward to having normal hearing again.

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