From
CreativeSpiral:
In the Light, from "Physical Graffiti" is one of Led Zeppelin's most unique, psychadelic synth driven songs. Composed primarily by John Paul Jones, if features unique melodic synth lines that were composed on Jones' EMS VCS3 synth, with delay effects. The low drone sound, which sounds like a Hurdy Gurdy, is said to have been played by Jimmy Page, using multiple overdubs with a violin bow on an acoustic guitar to create those long droning atmospheres.
In this patch, a SPLIT is used in Bi-Timbral mode to grant the separate low drone sound and melodic lead sound on top. The low drone incorporates several LFOs and and envelopes to get that warbling, droning, glitchy sound. Up top, the core sound is generated by square waves, and the onboard delay is used to get close to the album tone.
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