Pitch
Pitch is a subjective sensation, reflecting generally the lowness or highness of a sound. Human perception of pitch can be comprehensively fooled to create auditory illusions. Some people have what is called perfect pitch and can assign an isolated tone to its place on a musical scale. Perceived pitch is nearly always closely connected with the fundamental frequency of a note, with a lesser connection to sound pressure level, harmonic content of the sound, and to the immediately preceding history of notes heard. In general, the higher the frequency of vibration, the higher the perceived pitch is, and lower the frequency, the lower the pitch. However, even for tones of equal intensity, perceived pitch and measured frequency do not stand in a simple linear relationship. At and below about 1,000 Hz, the perceived pitch of a tone gets lower as sound pressure increases, but above approximately 2,000 Hz, the pitch increases as the sound gets louder. In Western music, there have long been several competing pitch standards defining tuning systems. The difference in frequency between two pitches is called an interval. The most basic interval is the unison which is simply two of the same pitch, followed by the slightly more complex octave, which indicates either a doubling or halving of the fundamental frequency.

Rhythm
Rhythm is the arrangement of sounds and silences in time. Meter animates time in regular pulse groupings, called measures or bars. The time signature or meter signature specifies how many beats are in a measure, and which value of written note is counted and felt as a single beat. Through increased stress and attack, and subtle variations in duration, particular tones may be accented. There are conventions in most musical traditions for a regular and hierarchical accentuation of beats to reinforce the meter. Syncopated rhythms are rhythms that accent unexpected parts of the beat. Playing simultaneous rhythms in more than one time signature is called polymeter.

Melody
A melody is a series of notes sounding in succession. The notes of a melody are typically created with respect to pitch systems such as scales or modes. The rhythm of a melody is often based on the inflections of language, the physical rhythms of dance, or simply periodic pulsation. Melody is typically divided into phrases within a larger overarching structure. The elements of a melody are pitch, duration, dynamics, and timbre. A piece of music may be melodically based. In this instance, a composer will first take a melody, and use that to create his or her work. A harmonically based piece, on the contrary, will focus on a chord progression, with the melody as a secondary or incidental factor of composition.

Harmony
Harmony is the study of vertical sonorities in music. Vertical sonority refers to considering the relationships between pitches that occur together; usually this means at the same time, although harmony can also be implied by a melody that outlines a harmonic structure. The vertical relationship between two pitches is referred to as an interval. A larger structure involving multiple pitches is called a chord. In Common practice and Popular music, harmonies are generally tertian. This means that the interval of which the chords are composed is a third. Therefore, a root-position triad (with the root note in the lowest voice) consists of the root note, a note a third above, and a note a third above that (a fifth above the root). Seventh chords add a third above the top note of a triad (a seventh above the root). There are some notable exceptions. In 20th century classical music, many alternative types of harmonic structure were explored. One way to analyze harmony in Common practice music is through a roman numeral system; in Popular Music and Jazz a system of chord symbols is used; and in post-tonal music, a variety of approaches are used, most frequently set theory. The perception of pitch within harmony depends on a number of factors including the interaction of frequencies within the harmony and the roughness produced by the fast beating of nearby partials. Pitch perception is also affected by familiarity of the listener with the music, and cultural associations.