Music theory is the study of the nuts and bolts of music. Quite simply, learn how music works and you can unlock a whole world of creativity.
The problem is that it's often taught in a very boring manner with no examples of actually how to apply it in the really world of music.
This bass tutorial explains the basics you need to know and demos how you might use these ideas in your bass playing.
Make sure to scroll down for more in depth tuition into the specific areas taught.
Half Step (Semitone) Whole Step (Tone)
Half step (or semitone) = 1 fret
Whole step (or tone/whole tone) = 2 frets
How high or low a note is. Musicians always talk in term of pitch which can make talking about playing notes on a bass neck confusing. Pitch explains this:
A collection of notes with a specific formula of whole and half steps.
A seven note scale with five whole tones and two half tones. These cover the major, natural minor, and modes that come from them.
Every major scale has a minor equivalent, built from the sixth degree, that contains exactly the same notes.
The distance between two musical pitches and the basis of all melodies (and bass lines).
The first, third, and fifth notes of a scale or mode. Loads of bass lines use these simple notes.
Arpeggio (Chord Tones)
Add an octave or seventh to a triad and you get an arpeggio (or broken chord since it's the notes of a chord played separately rather than at the same time).
Three or more notes played together at the same time.
Two notes played at the same time.
Tony Levin loves these! How To Play Don’t Give Up, TONY LEVIN (Breakdown & Lesson)
Accidentals: flat, Sharp, natural
When you go up a fret you sharpen (#) a note. Going down flattens (b) it. A natural sign cancels an accidental (the sharps and flats). You can get double sharps and flats but they're quite rare.
A scale built from a 'parent' scale - usually the major, melodic minor, or harmonic minor.
A scale used a lot in jazz (due to its use of tense and interesting intervals).
Formula: W H W W W W H
W = Whole step
H = Half step
Think major scale with a b3.
Another exotic sounding scale with a bunch of cool modes.
Formula: W H W W H W+H H
Think natural minor with a major 7th.
When you place a note other than the root note as the lowest in a chord, you have inverted it. They are represented by slash chords.
A C chord = C (C E G)
C/E is inverted, so E is in the bass: E G C.
Same notes, just turned upside down. This leads to smoother chord progressions and smaller movements between the lowest notes in music.
The study of notes played together.
Nashville number system
A system of musical notation developed in Nashville. Most known for its labelling of chords within a key.
Roman numerals are used - upper case for major, lower for minor.
CMaj7 Dm Em FMaj7 G7 Am7 Bm7b5
I ii iii IV V vi vii
How music is made by choosing what chords sound good together.
If a piece of music uses notes from the C Major scale, it is in the key of C. Some songs stay in one key, others change to different keys. Major keys sound bright and happy, minor keys dark, and sad.
Modulations occur when you change key. A common key change in pop is going up a tone. Cheesy but effective! Listen to Beyonce's Love On Top for an extreme example...
Circle of fifths
A system of categorising and memorising major and minor keys.
The description for chord progressions that don't fit to a diatonic key.
Dynamics describe contrasts in music - loud/soft, fast/slow etc. Italian terms are used, such as forte for loud, piano for quiet and crescendo for gradually getting louder.
In practice, non-classical musicians rarely use those Italian words but it's good to be aware of them and to be able to control dynamics.
Time signatures & Meter
The organisation of rhythms into ordered units.
A special rhythm for 1/8th notes (and also 1/16ths) used a lot in jazz and blues.
Rhythms are so important for bass players. Here are the most common: The Most Common Rhythms & How To Make Bass Lines With Them (Also How To Play In Time)
Rhythms that stress the off beats rather than the on beats. They sound exciting and unpredictable and are used a lot in funk music.
That didn't cover everything to do with music theory but it's a good start! Listen out for these concepts in the wild as that connection is how you will learn to deeply understand music.
Once you go down that road, you'll be able to create easily plus teach yourself music.