Mellotron

After several early lineup changes, in 1967 they released “Days of Future Passed,” considered one of the first prog-rock albums, which also saw Pinder’s debut recording with a Mellotron — an early electro-acoustic keyboard that uses manipulated tape loops to create an otherworldly orchestral sound.

Mike Pinder, the last surviving founding member of the Moody Blues, whose innovative use of the Mellotron — a predecessor of the sampler — helped make the band a pioneer of progressive rock, died on Wednesday at his home in the Sacramento area.

Mr. Pinder had worked as a tester in the Mellotron factory in Birmingham, England, before the Moody Blues formed.

Khosla often has it performed on solo piano or string quartet, or — like in the main titles — sung by an artificial choir created by a Mellotron.

Their sessions, tracking instruments like pedal steel and Mellotron, along with birdsong from Lewis’s Nashville backyard, flowed easily.