We can think of sound as a wave, similar to waves you can watch while sitting on the beach, drinking your piña colada, and (oh, I digress again). A wave is the result of a repeating movement or vibration of molecules or particles in some substance, such as water or air. Using the visual concept of waves you can see at a beach, I would like to introduce some useful wave terminology. Between sips of your favorite beverage, you can look out over the sea and focus in on a single wave while it is still some distance from the shore. While you keep watching it, the wave seems to roll in toward the beach. That traveling motion of the wave is called propagation. You may notice that some waves appear larger than others. The size or magnitude of the wave is its amplitude. In most cases at the beach, the time between waves seems to be pretty constant. I have never actually done this, but if you count the number of waves you see over the course of five minutes, and then do it again some time later, you will probably see nearly the same number of waves. (You would have to count all the waves, the huge ones and the tiny ones.) That number of waves over a period of time could be called the rate of vibration or the frequency.
If you're a more visual person, this might help somewhat. . .
Sandy Point, Tobago (in case you're wondering)
Hopefully you're not getting seasick (or bored out of your mind). Hang on just a tad longer, and I will show how this relates to music.
Each of these properties of a wave at the beach - propagation, amplitude and frequency - can also apply to the little ripples made when you drop a rock into a pond, or the somewhat larger ripples created when you do a cannonball into a swimming pool. You make a disturbance in the water and the water starts moving in a wavy motion. Sound works the same way at a much smaller level. Clap your hands, or strike something, and you create a disturbance in the air that moves in such a way that your ears detect the disturbance.
Here's the musical connection. When we detect the sound with our ears we call that hearing. Our sense of space or direction related to a sound is usually related to propagation. This is because we can hear the direct sound from the source to our ears. Our ears are a small distance apart, so the sound reaches each ear at a different time. We also hear the sound again as it reflects off other objects, like walls, floors or ceilings (or we notice when the sound does not reflect). The physics of all of this gets processed by our brains as a perception of the space we are in -- Big or small, open or closed, muffled or noisy. When we hear the amplitude of a sound wave, we call it volume. When we hear the frequency of a sound wave, we refer to it as the pitch. There's one more very important property related to frequency, but we're going to save that one for later. In music production, we are controlling these properties of sound (amplitude, propagation, frequency and the mystery property) to alter what people hear (volume, space, pitch and the mystery property). Maybe what you hear is real, or maybe it was manipulated by a producer in a studio. Or maybe there is a combination. In the next few articles, we'll introduce briefly how a music producer can influence or control these characteristics.
There's more to each of these characteristics of sound, but you need a break to go make some music. So do I!
No comments:
Post a Comment