In popular music, half-time is a type of meter and tempo that alters the rhythmic feel by essentially doubling the tempo resolution or metric division/level in comparison to common-time. Thus, two measures of approximate a single measure of, while a single measure of 4/4 emulates 2/2. Half-time is not to be confused with alla breve or odd time. Though notes usually get the same value relative to the tempo, the way the beats are divided is altered. While much music typically has a backbeat on quarter note beats two and four, half time would increase the interval between backbeats to double, thus making it hit on beats three and seven, or the third beat of each measure : 1 2 3 4 1 2 3 4 1 2 3 4 5 6 7 8 1 2 3 4 Essentially, a half time 'groove' is one that expands one measure over the course of two. The length of each note is doubled while its frequency is halved.
Common-time
Time signatures are defined by how they divide the measure. In "common" time, often considered, each level is divided in two. In a common-time rock drum pattern each measure is divided in two by the bass drum, each half is divided in two by the snare drum, and each quarter note is divided in two by a ride pattern. "Half"-time refers to halving this division, while "double"-time refers to doubling this division.
Half-time
A classic example is the half-time shuffle, a variation of a shuffle rhythm, which is used extensively in hip-hop and some blues music. Some of the variations of the basic groove are notoriously difficult to play on drum set. It is also a favorite in some pop and rock tunes. Some classic examples are the Purdie Shuffle by Bernard Purdie which appears in "Home At Last" and "Babylon Sisters", both of which are Steely Dan songs. "Fool in the Rain" by Led Zeppelin uses a derivation of the Purdie Shuffle, and Jeff Porcaro of Toto created a hybridization of the Zeppelin and Purdie shuffles called the Rosanna shuffle for the track "Rosanna". It is important to realize that while in half time, the feel of notes are chopped in half, but the actual time value remains the same. For example, at the same tempo, 8th notes would sound like 16ths. In the case of the half time shuffle, triplets sound like 16th note triplets, etc. By preserving the tempo, the beat is stretched by a factor of 2.
Double-time
In music and dance, double-time is a type of meter and tempo or rhythmic feel by essentially halving the tempo resolution or metric division/level. It is also associated with specific time signatures such as. Contrast with half time. In jazz the term means using note values twice as fast as previously but without changing the pace of the chord progressions. It is often used during improvised solos. "Double time doubling a rhythm pattern within its original bar structure.": 1 2 3 4 1 2 3 4 1 2 3 4 It may help to picture the way musicians count each metric level in 4/4: quarter: 1 2 3 4 eighth: 1 & 2 & 3 & 4 & sixteenth: 1 e & a 2 e & a 3 e & a 4 e & a
