A note is a sound or tone having two aspects: the primary, auditory one, is pitch; the secondary, temporal one, is duration called time value or note value. Each note has a unique pitch, with a sound wave frequency measurable in hertz. In many parts of the world instruments are tuned to A at 440Hz. When written or played notes also have duration, the note value, which indicates how long the note lasts relative to the .
Musicians often talk about notes without reference to duration, referring solely to its pitch. The note “C” or “A” for example. Duration becomes relevant when playing the notes, or writing them on paper (or pixels).
Notes have other qualities, including and . These things can be written on the page but they are really performance aspects, how to shape the sound and quality of the notes. When notes are played one after the other we get rhythm. I don’t need to talk about these things here.
Read Scales, Keys, and Key Signatures for an explanation how notes are organized in the scale system.
There are 7 different letters used to name notes: A through G. Notes are written on a staff, also called stave, which is five horizontal lines and the four spaces between them. On its own a staff is meaningless. To identify note names, and their specific pitch, every staff requires a clef. In order to understand how notes are named on a staff I have to first explain clefs.
Below is a two octave C major scale in the treble clef. The treble clef is the backwards looking S-like object at the beginning of the staff. The treble clef is actually a stylized G. The line second from the bottom runs through the widest part of the clef, where the loop with an inner loop circles around the line. Since the treble clef is a fancy G, the line it wraps around is called “G”. The note positioned such that the “G’ line runs through its head (the round or oval part) is therefore called G. Notes are named alphabetically up and down from that line, using only the letters A through G. After G the names start over from A.
And here is a two octave C major scale in the bass clef. The bass clef sign is a stylized F. It starts near the top left on the second line from the top, and there are two dots in the top two spaces on either side of the line. Since the bass clef is an F, the line it highlights is called “F”. The note positioned such that the “F’ line runs through its head is therefore called F. And again, notes are named alphabetically up and down from that line, using only the letters A through G. After G the names start over from A.
Piano music combines the clefs. The note C, called middle C, is exactly between the clefs – in the middle. (I couldn’t get it centered between the clefs with the notation software.) Middle C is one ledger line below the treble clef and one above the bass clef. Ledger lines are the short lines above and below the standard five lines. They extend the lines and spaces.
Middle C is the same pitch in both clefs. The two octave C major scale beginning in the bass clef and flowing into the treble clef, transitioning on middle C, should clearly illustrate the relationship between the two clefs.
There are several other clefs, which we can ignore. I’ll never need to use them when writing about tango music.
We know how notes without accidentals get their names. Accidentals is the collective term for sharp, flat and natural. There are 12 different notes and naming some of them requires using the terms “sharp” and “flat”. Recall a sharp raises the note a semitone and a flat lowers it a semitone. The letter name does not change because the note is still positioned on a staff. The term “sharp” or “flat” is simply added to the note name as necessary. (Sometimes notes have two sharps or two flats. In those cases “double sharp” or”double flat” is added to the letter name.) C# is read and said as “C sharp”, Bb as “B flat”.
The chromatic scale uses all 12 notes. I used sharps when ascending and flats when descending to cover all the possibilities, using single sharps and flats. Notice the scale sounds the same when ascending and descending, even though sharps are used on the way up and flats on the way down. Enharmonic notes are notes with the same pitch but different names. C sharp sounds the same as D flat, E flat sounds the same as D sharp, for example. Click those notes, or any other enharmonic pair, in the following example to verify. Enharmonic notes are the exception to the rule that each note has a unique pitch.
C chromatic scale in the treble clef:
There are a couple standardized systems used to specify the note’s octaves. Rather than have everyone learn them, if I need to be specific about the octave I will simply write “an octave above middle C”, or something like that.
Beat is the underlying and regularly spaced pulse of the music, measured in beats per minute. There are a fixed number of beats in a bar, indicated by the time signature. Tango (2/4, 4/8, 4/4) has 2 or 4 beats per bar, vals (3/4) has 3 and milonga (2/4) has 2.
(There may be a sense of 4 beats even though the time signature is 2/4. Tango very often subdivides the 2/4 beat, doubling the count from 2 to 4, effectively using a 4/8 time signature. Some tango music is explicitly written in 4/8, most are in 2/4. See Tango Time Signatures and the Beat).
Dynamics is the volume factor in music. There are two broad categories: a relative volume level which does not change until some marking specifies it does; and a volume that changes gradually or suddenly.
The way the notes are played and connected to one another: anywhere from gently played to heavily attacked; held for the full duration of the note value or clipped short; smoothly connected to the notes before and after, or continuously separated.
There are many technical terms for these differences, but for tango we mostly need to be aware of two broad kinds of articulation, the extreme ends of the spectrum: a connected legato, which often creates a lyrical quality, and an accented, clipped short marcato. Generally, the strings and singers have a legato articulation, while the bandoneons have a marcato one.