In theory, there is resonance and dissonance. Resonance creates harmony and dissonance creates tension (as a general rule). Each interval (2-7) has different levels of Resonance. The 3rd and the 5th are generally the most resonant notes in a scale. Another way of putting it is they are “more compatible” with 1 (your tonic note). When you get back to 1 you have “resolved” a musical phrase. So by having the 5 be the note you play before “resolving” on the 1 is kind of audibly suggesting you are going back towards the resolve that people are unconsciously craving to hear. Kind of builds musical anticipation. If you go from a dissonant note to resolving it can sound sudden or rushed (which you might want depending). But a 5 is very safe, very familiar and almost always works.
To clarify this info, have you ever put your finger on the wrong fret and hit a “sour” note that sounded bad? Chances are you played either a more dissonant interval, or a chromatic note (just a note that isn’t in the scale you are playing). Why do chromatic notes tend to sound “sour”. It is because they are the MOST dissonant notes you can play in the scale (not technically in the scale lol).
Depends on time signature, varied factors. There are songs with 3 and 2. Something in the Way by Nirvana has 2 root notes that alternate back and forth during the verse. Sometimes bassists just ride the 1 on 8th notes for a lot of a progression. It’s more a tool in the belt than a hard and fast rule.
No epiphany yet but I am starting to see a dim light in the distance. Guess I need to grab my page of scales and my Bass and start picking out notes to see what sounds good/right together. Thanks you for all your help. I’m sure I’ll have more questions after some of this has sunk in.
