Temperature / Period “Time” / Frequency / Wave Length / Note ID

In my opinion, when it comes to a complicated system, more information is better than less information. This goes for a simple computer, car dashboard, airplane control panel and certainly a measurement rig. When you are presented with related data such as the outside temperature in Fahrenheit and Celsius you begin to learn how they relate to each other. Not true if you are using only one temperature scale. Since temperature affects sound, we should understand temperature scales.

Celsius = -17.7778 / Fahrenheit = 0
Celsius = 0 / Fahrenheit = 32 (freezing point of water)
Celsius = 37 / Fahrenheit = 98.6 (average temperature of a human)
Celsius = 37.778 / Fahrenheit = 100
Celsius = 100 / Fahrenheit = 212 (boiling point of water)

The Fahrenheit temperature scale seems to be more useful for discussing human environments as 0 degrees is pretty cold and 100 degrees is pretty hot.

Celsius is the perfect temperature scale to discuss different states of water. 0 to 100

But knowing both scales and how they relate to each other is obviously a superior approach than choosing only one or the other. The same is true for audio. It’s vital that we can think in period (time), frequency (Hz) and wave length (distance) if we’re going to see “the big picture” as it relates to the data a measurement rig provides. I’ll add onto that list of related values the note ID since most of us in the professional audio industry are working in music. If our measurement instrument can provide us with all of those at the same time, obviously the relationship between them all becomes much clearer over time. In that way we quickly learn that a 1k frequency is approximately 1.1 feet long. Then logic can fill in the blank that a 10k frequency is approximately .11 feet long and 100hz is 11.1 feet long. Going further, 500hz is 2.2 feet long, 50 Hz is 22 feet long & 5k is .22 feet long. Ad infinitum.

Once you recognize the relationship between a frequency, wave length and period, it’s much easier to recognize trends on your measurement rig and to anticipate how one decision will affect another. Audio measurement 101 is learning the tools and understanding what the instrument is telling you. Audio measurement 102 is about anticipating what the instrument should reveal and understanding what is going on if it doesn’t. As 6o6 stated in his class, he places his mics where he wants to see something, not the other way around. Meaning you put the mic where you want to measure and then aim the speaker at the mic. When the mic measurement shows the expected result, you’re properly aimed. Makes too much sense!

Here is a calculator for converting between decimal feet and fractions of feet.
daveosborne.com – decimal feet