Reggae is most identifiable by its off-beat accents. Reggae is commonly misconstrued to refer to all Jamaican music, but reggae refers to a specific type of Jamaican music. Reggae gathers its influences from African music, jazz, rhythm and blues and, more directly, ska and rocksteady. Ska during the 1960s was popularized in Britain by the mod culture and in Jamaica by the rude-boy culture. Neither group liked the speed of ska, so they would "dance half-speed to certain ska records," according to reggae historian Steve Barrow. This led to the creation of rocksteady and then reggae.
Reggae is played most commonly in 4/4 or swing time. 4/4 is the most common time signature, with four quarter beats in a bar. Swing time takes a simple time signature, such as 4/4, but plays notes or chords at untypical times, such as four sets of three notes in two bars of 4/4.
Reggae drums are divided into three categories. "One drop" emphasizes the third beat, with no drum on the first beat. "Rockers" emphasizes the third beat as well, though it features a drum (usually a bass drum) on the first beat as well. "Steppers" has a bass drum for each beat; in other music genres, this is know as "four on the floor."
Bass is one of the most prominent aspects of reggae music. It is played with no high-frequency range, and low frequencies are turned up to emphasize the bass sound. Sound frequencies are measured in terms of the vibrations a sound will produce. High-frequency instruments include the flute, piccolo and violin. Low-frequency instruments include the bass, bassoon and tuba. An amplifier or sound-mixing desk can alter the frequencies amplified from instruments. Bass lines are often simple riffs repeated throughout in reggae music. A riff is a sequence of notes in a small number of bars that can be repeated.
Reggae guitar usually incorporates chords on the second and fourth beats of a bar. Guitar-playing is short, meaning the strings are plucked quickly and sharply. Reggae guitar is also often played in upstrokes–the guitarist strums chords in an upward direction from the highest-pitched string to the lowest, producing high-pitched or high-frequency sounds.
Piano in reggae is played in staccato–marked by short, clear-cut playing–in time with the guitar to match and double the rhythm section. Piano is seldom featured on its own and as an accompaniment only to the guitar. In the late 1970s and early 1980s, pianos and keyboards were replaced by synthesizers.
Saxophone, trombone and trumpet are the most common horn instruments in reggae music. Usually the first horn plays a simple melody, with the second horn playing the melody an octave higher and the third horn a fifth higher than the second. Horn sections in reggae are often used to introduce a song, or during a break. It is uncommon for a horn section to play throughout the entire song.