Together with Tony Clarke, engineer Derek Varnals also contributed heavily to the creation of the Moody Blues' classic studio sound, working with Pinder and Clarke to create a more symphonic overlapping sound on the Mellotron as opposed to the sharp 'cut off' the instrument normally gave, partly achieved by removing all the "sound effects" tapes (trains, whistles, cockerel crowing, etc.) and then 'doubling up' the tapes of orchestral instruments' sounds, which combined with Pinder's knowledge of the instrument and ability at playing it, and Clarke and Varnals' recording skills, created an orchestral 'wave' sound that characterised the Moody Blues' music thereafter.