SATB 

When someone say SATB, you start thinking of different words it can mean. SATB refers to a four part chords structure. Soprano, alto, tenor and bass. A built structure chord that can starts on the tonic, the dominant and the predominant.

When writing music sometimes you may see notes with numbers. That's showing you that they belong in a specific octave. There different numbers base on the octave or ranges they can sing. As a Soprano there octaves or range can go from a C4 to a C6 and an Alto ranges from G3 to G5 and base on the picture you can see the other types of ranges for the other low parts.

When writing a 4 part chordal structure there are notes you can not double, but some you can. 

You can be able to double the root, and the third. In some instances you can double the third which is rarely, but that usual occurs in seventh chords. Just how there are some chords or notes you can double there’s notes such as Tendency notes you can not double. 

We also explored on open and closed chords. 

Closed chords are what it is called, close chords which has it in close proximity. The notes aren’t spread through the staff. Open chords has all the notes apart from each other onto their own staff. Upper voices use the treble staff and lower voices uses the bass clef. 

In lower voices the the bass doesn’t have a choice to move far. Bass shouldn’t move more than an octave or else it would not work together. 

You can always use the extra help when doing theory or voice leading. Voice leading works with inversions and there are different types to help you voice your music. You have first second and third inversions. First inversion is is the 3rd in the bass also called (6/3) Second inversion is the 5th in the bass also called (6/4) Third inversion is the 7th in the bass.  

This teaches you about chord inversions and how to identify the inversions. You can also see the difference with the open and close chords.