Minor nitpick: it's a "dyad" that is a combination of two notes.
An "interval" is the difference between two (or more) pitches. And just as you'd measure the space between your eyebrows using a ruler, you'd measure the interval between middle C and concert A using your ears.
The bonus, however, is that our listening apparatus is already quantized to octaves-- if you hear a pitch against a second pitch that's double/quadruple/etc. the frequency of the first, your ear marks this interval as special. It's likely most of you've already used this fact to your advantage; perhaps unwittingly, when someone begins singing "Happy Birthday" outside your normal singing range. (Though most renditions of "Happy Birthday" lend credence to Morpheus' lesson from The Matrix that there's a difference between knowing the path and walking it.) :)
Minor nitpick: it's a "dyad" that is a combination of two notes.
An "interval" is the difference between two (or more) pitches. And just as you'd measure the space between your eyebrows using a ruler, you'd measure the interval between middle C and concert A using your ears.
The bonus, however, is that our listening apparatus is already quantized to octaves-- if you hear a pitch against a second pitch that's double/quadruple/etc. the frequency of the first, your ear marks this interval as special. It's likely most of you've already used this fact to your advantage; perhaps unwittingly, when someone begins singing "Happy Birthday" outside your normal singing range. (Though most renditions of "Happy Birthday" lend credence to Morpheus' lesson from The Matrix that there's a difference between knowing the path and walking it.) :)