Electro (short for either electro-funk or electro-boogie) is a genre of electronic music directly influenced by the use of TR-808, Moog keytar synthesizers and funk sampling. Records in the genre typically feature drum machines and heavy electronic sounding deprived of vocals in general, although if present, they are delivered in a deadpan manner, often through an electronic distortion such as vocoding. This is the main distinction of electro from previously prominent late-1970s genres such as disco and boogie, in which electronic sound was only part of the instrumentation rather than basis of the whole song.
From its origins, the definition of the electro sound is the use of drum machines as the rhythmic base of a track; however as the style has evolved, and with the advent of computer usage in electronic music, the use of drum machines has become less and less practical and widespread. Electro drum patterns tend to be electronic emulations of breakbeats, with a syncopated kick drum, and usually a snare or clap accenting the downbeat. The difference between electro drumbeats and breakbeats (or breaks) is that electro tends to be more mechanical, while breakbeats tend to have more of a human-like feel, like that of a live drummer. The definition however is somewhat ambiguous in nature due to the various use of the term.
Staccato, percussive drumbeats tend to dominate electro; with beats once mostly provided by the Roland TR-808 drum machine, the advent of computers in electronic music has outdated this old school method and are now used by the majority of electro producers the world over. The TR-808, created in 1980, has an immediately recognizable sound, and through the use of samples remains somewhat popular in electro and other genres to the present day. Other electro instrumentation is generally all-electronic, favoring analog synthesis, bass lines, sequenced or arpeggiated synthetic riffs, and atonal sound effects all created with synthesizers. Heavy use of effects such as reverbs, delays, chorus or phasers along with eerie synthetic ensemble strings or pad sounds emphasize the common science fiction or futuristic theme of the lyrics and/or music. Most electro is instrumental, but a common element is vocals processed through a vocoder. Additionally, speech synthesis may be used to create robotic or mechanical lyrical content. Some earlier electro features rapping, but that lyrical style has become less popular in the genre from the 1990s onward.