Somewhat off topic, but he did a concert in Copenhagen of which there's a full recording on Youtube [1] For something filmed in 1967 the audio quality is absol

Somewhat off topic, but he did a concert in Copenhagen of which there's a full recording on Youtube [1] For something filmed in 1967 the audio quality is absolutely stunning. I wonder what equipment they used? My suspicion is that it's a piezoelectric microphone which had fantastic reputation for picking up a wide range of sound (especially for things like multiple people around a table) but fell out of favour as they worked best with valve amplifiers. [1] https://www.youtube.com/watch?v=QHPmRJIoc2k https://www.youtube.com/watch?v=QHPmRJIoc2k