What is sound? It seems like a silly question, everyone knows what sound is right? If you had to describe sound to someone who didn't already know what is was, what would you tell them? Some would say, "Sound is something that you can hear." Another would say, "Sound is something that makes noise." Sure, technically these descriptions are correct, but if you truly did not know what sound was then these descriptions would only create more questions. For example, if sound is something you can hear then what is the processing of "hearing"? If sound makes noise then how is "noise" defined?
Defining sound is not only important in an abstract discussion, but it's even more important when you need to design and produce devices that create and work with sound. What are the components of sound that allow us to create, modify and project it to other people, our audience. And what are the characteristics of sound that affect our audience's ability to hear this sound.
In this post we'll explore 3 core elements of sound that help us start to answer these questions. These elements are (1) Definition of Sound, (2) Frequency, and (3) Amplitude.
Sound can be defined as a waves of vibrating molecule chains. Right away you'd say that this definition applies to other waves besides sound. For example, waves in the ocean. Ocean waves are chains of water molecules in motion. Or how about light? Light consists of electromagnetic radiation waves. These are both true, but what makes sound unique is that sound contains waves of vibrating AIR molecules. Our ears have biology that allows us to detect these waves of vibrating air molecules and converting them into electrical signals for our brains to build meaningful information from. The type of waves we deal with most in the study of sound is the sine wave, which we'll use much more as we learn about sound.
The next major characteristic of sound is Frequency. A generic definition of frequency is how many times something occurs in a particular amount of time. That's a good definition, but we need to know how frequency applies specifically to sound. Frequency, as it applies to sound, is how often our sound wave moves through the air – or - how many "cycles" in one second. Frequency is measured in Hertz (Hz). A frequency of 800Hz consists of 800 full sine waves passing through a point in one second. As we progress into the study and use of frequency we'll learn about a term called "fundamental voice frequency" and it's use in harmonics. But let's not get ahead of ourselves just yet, there'll be plenty of time for that later.
Next we'll talk about Amplitude. We often use amplitude as the main indicator of strength of a sound wave. Amplitude is defined as the maximum height or depth of a wave. The height and depth of a sound wave (how much air is actually moved) is the amplitude and is directly proportionate to how loud or soft an audible sound is. Sounds of higher amplitude are louder. Sounds of lower amplitude are lower, or softer. We commonly refer to the amplitude as the "volume" of the sound.
We'll stop here for now and invite you to do more research about frequency, amplitude and their various uses. You'll notice right away that they are very common terms, used in fields of study from quantum physics to personal training. You'll also notice a startling amount of math and formulas associated with these terms, but don't get intimidated. Math is just a way to represent common language in a distinct and repeatable manner. Beware of anyone explaining something to you purely in complex mathematical terms, without making it clear what it is the math represents - that probably means they don't truly understand it themselves. You can't have math without a common everyday intuitive grasp of what you're working with - and that's what we're going to focus on. You grasp that and the math comes easy.
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