The "Wall of Sound" was the hallmark production technique of '60s producer Phil Spector. Rather than recording each part of a song on a separate track, Spector had the musicians play simultaneously into a single microphone, which he then further compressed by converting the recording to monophonic sound. This production technique created a dense, ear-catching sound that overpowered everything else on the radio. Spector pioneered the Wall of Sound on records like the Ronettes' "Be My Baby" and The Crystals' "Then He Kissed Me"; he later used it on productions for artists as diverse as The Beatles and The Ramones.
The development of multitrack recorders in the 1960s opened up a new world of sonic possibilities. Before the '60s, producers were limited to recording onto one or perhaps two audio tracks. Multitrack recording let them overlay four or even eight tracks together to create a song. Seminal albums like The Beatles' "Sgt. Pepper's Lonely Hearts Club Band" and The Beach Boys' "Pet Sounds" used multitrack recorders to create their rich, layered sonic landscapes.
Technological innovations in the '60s led to the development of reverb effects boxes. Previously, producers could create a reverberation effect only by using an "echo chamber," which was a room designed to cause sound to reverberate in a certain way. Tape-based reverb and echo effects allowed producers to create reverberation without using a physical space; they could also simulate cavernous echoes without the expense involved in actually setting up the physical space. Dick Dale's surf rock recordings are a prime example of the importance of reverb to the '60s sound.
In the 1960s, computers and synthesizers started to become relatively affordable and accessible. Robert Moog started building and marketing modular synthesizers in the mid-1960s; bands like The Doors and The Beatles quickly began integrating Moog synths into their music. Experimental and avant-garde musicians like Morton Subotnik and minimalist composer Terry Riley began to explore the possibilities of electronic music, while the BBC's Radiophonic Workshop used electronic instruments to create music for the television network, including the classic "Doctor Who" theme song.