A measure has an equal number of counts, and 4 measures is a bar:
This is 1 bar of 4 measures, with 4 counts/beats per measure.
A full measure may have 2, 3, or 4 beats:
This would be one measure of 2, 3, or 4 counts, respectively.
Bars hold the phrases we play, usually contain 4 measures, and are like sentences to a paragraph. Sheet music has a vertical line (called a bar line |) that separates measures. Count 4 beats, and do it four times, to get 1 Bar:
Why are Bars important? Music is governed by symmetry (equality), and 4 feels like a good place to begin and end things. Perhaps the mind can take in only so much at once, until it says, 'give me something else'. A listener may get bored after they latch onto the first rhythm.
Note the difference between one measure, and a whole bar of measures. Musical phrases make up a bar, whereas measures hold only parts of a phrase in equal counts. So a bar seems like a little song in itself.
To keep track of the bars, you may use the measure number for the first count of each measure:
This way of counting measures reminds you where in a bar you're playing or resting. And it helps keep track of the background Beat, since an entire song is made up of many Bars. Modern music usually divides the Beat into 4 Bars:
This is 4 Bars , with a Beat of 2. If that's confusing to you, just notice the underlined counts, and emphasize them out loud when you're counting measures (1...2...3...4). When counting, you only have to remember 4 numbers.
Again, a Measure is the total count between the bar lines, such as |1,2,3|. A Bar is all the measures linked together, usually 4 measures:
Playing a bar gives a sense of completion, before the start of the next bar.
In sheet music, a Triplet will have this notation over three notes:
Tri- means 3, of course, and triplets are 3 notes of equal length. They can be played in any duration of a measure, and sometimes are played across more than one measure. Whether the count is 2, 3, or 4 beats per measure, a Triplet may occur at any place in the measure:
...where the triplet of 3 notes occurs after the 4th beat. The triplet must be quickly played, before the 1st beat of the next measure.
...with the triplet after the first count.
...with the triplet even before the first count. In these cases, the triplet's notes are quite short.
...notice here that the 3 note triplet takes up the whole measure, yet we're playing in the count of 4. "What? We can't have only 3 counts in a measure of 4 beats!" We can if we space out the 3 notes of a Triplet within the same duration of time as the other measures of 4 counts. Play the 3 note triplet a little slower (within the duration of 4 equal counts). In this case, the triplet's notes will hold longer.
Each note in a Triplet must be equal lengths of time, or duration. One note is not longer or shorter than the other. And after the triplet, continue with the normal count of the measure. To get a feel for where a triplet falls in the beat, mentally think, tri, pl, et, for 3 equal notes (sounds). Three door knocks is a triplet.
Triplets break up the regularity of the count, and add flair to notes. Triplets can be the same note (tone), or all different notes. As we saw, Triplets may be a full measure, or a quick preface to only one note in a measure.
So that our mind won't freak over how many beats should be in a measure, just play the three notes within whatever duration the measure should have, with 3 equal note lengths. It's all about odds versus evens. Two triplets together make up a Sextuplet (123,456)(tri,pl,et tri,pl,et).
Listen to the sample below that has two sextuplets (only one image) that lead into a downbeat note (123456, 123456, 1):
The Circle of Fifths is just a reminder tool for the number of sharps or flats in different keys, Major or minor. The outside or capital letters are for the Major Keys, and the inside or lowercase letters are for the minor keys. As you go clockwise or counterclockwise around the circle, you add one more sharp or flat.
Going around the circle clockwise (right side), each root note is five half steps below the previous one: CGDAEBF
Going counterclockwise (left side), each root note is five half steps above the previous one: CFBEADG
More important is knowing the number of flats or sharps for our root note.
In like manner, minors have the same number of sharps or flats as the Majors, so they are named relative minors. The relative minors are 3 half steps down from their Major Key.
To get a minor key, take the Major root, drop down three half steps, to the minor note root note, and keep the same number of sharps or flats. C Major's relative minor is 'a' minor, with the root of 'a' (c-b-a#-a is 3 half steps, going down). The 'a' minor triad would be:
Eb Major's relative minor is 'c' minor, with 'c' as the root, and the triad as:
D Major's relative minor is 'b' minor, with the root note of 'b'. And the 'b' minor triad is:
Count only the half steps between the letters, not the letters themselves. So backwards from DMaj to bmin is 3 half steps:
Now b is the minor's root, with the same key signature as D Major, 2 sharps (f#,c#).
The next page has practice to learn the notes within these keys.