Mary Ford, featured a then-significant amount of overdubbing, along with other studio techniques such as flanging, delay, phasing and vari-speed. Les Paul's advancements in recording were seen in the adoption of his techniques by artists like Buddy Holly. In 1958, Holly released "Words of Love" and "Listen to Me," which were composed with overdubbing for added instrumentation and harmonies. Peter Ustinov performed multiple voices on "Mock Mozart", in a recording produced by George Martin. Abbey Road Studios had no multitrack recorders at the time, so a pair of mono machines were used. Martin used the same process later for a Peter Sellers comedy record, this time using stereo machines and panning. Examples Overdubs can be made for a variety of reasons. One of the most obvious is for convenience; for example, if a bass guitarist were temporarily unavailable, the recording can be made and the bass track added later. Similarly, if only one or two guitarists are available, but a song calls for multiple guitar parts, a guitarist can play both lead and rhythm guitar. Overdubbing is also used to solidify a weak singer; double tracking allows a singer with poor intonation to sound more in tune. (The opposite of this is often used with sampled instruments; detuning the sample slightly can make the sound more lifelike.) The effect is used to give one singer a fuller sound. They would effectively harmonize with their own vocals, like a choir but with just one voice. Overdubbing has sometimes been viewed negatively, when it is seen as being used to artificially enhance the musical skills of an artist or group, such as with studio-recorded inserts to live recordings, or backing tracks created by session musicians instead of the credited performers. The early records of the Monkees were made by groups of studio musicians pre-recording songs (often in a different studio, and some before the band was even formed), which were later overdubbed with the Monkees' vocals. While the songs became hits, this practice drew criticism. Michael Nesmith in particular disliked what overdubbing did to the integrity of the band's music. Additionally, in working with producer Butch Vig, Kurt Cobain had expressed a disdain for double-track recording. Vig had to reportedly convince Cobain to use the recording technique by saying, "The Beatles did it on everything. John Lennon loved the sound of his voice double-tracked." Paulinho da Costa's song "Ritmo Number One" from