Yesterday's Blogging A-to-Z challenge post introduced the four principal scales used to create melodies in Western music for the past five or six centuries. Today I want to talk about the opposite of a melody: the bass line.
Take this familiar melody:
It's pleasant enough, but a little thin. It needs...more. So let's add a bass line below the melody, just using the notes C and G:
Hey! It's almost music now!
So what's going on here? Without going too much into how harmony works (the topic for next Tuesday), all I've done is add a few Cs and Gs to the lower line. (We'll get into clefs tomorrow; for now, the bottom line is played lower than the upper line, and they meet at the aptly-named middle C, which is the note floating on its own little shelf above the lower line.)
This works because the 1st and 5th notes of a scale (the tonic and dominant) are the most important. A lot of bass lines, particularly in popular music, just emphasize these notes. Listen to the bass line in Aerosmith's "Sweet Emotion:" it only hits the tonic, and keeps hitting it, through the whole song.
Or take Chicago's "25 or 6 to 4." The bass line just repeats the dominant through the tonic notes of the descending D-minor scale (A, G, F, E, D) over and over again. (This is called an ostinato bass.)
As a bonus, I had a little fun with the "London Bridge" example, which I'll probably come back to later this month. Enjoy: