Classic British radio comedy show, The Navy Lark, ran between 1959 and 1977 bringing Leslie Phillips, Jon Pertwee and Ronnie Barker into millions of lives. Now the complete run is becoming available again as AudioGo, the home of the BBC’s audio books, releases The Navy Lark Collector’s Edition series, which will eventually contain every episode broadcast in those 18 years.

‘Many of the episodes were not kept by the BBC and others only existed as edited versions for Transcription Service issue’, explains project engineer and former BBC sound engineer, Ted Kendall. ‘So I had to source the missing material from wherever it could be found. One source proved particularly valuable…

‘I discovered that another BBC engineer had taped many of the episodes at home on his Ferrograph recorder. He did so from the VHF transmissions and, because his equipment was skilfully used, it should have been possible – with a touch of Cedar restoration and equalisation – to make them sound like studio tapes. Unfortunately, the recorder was usually operated by a time switch, and it drifted in speed by up to six per cent as it warmed up during the course of each half-hour programme.’

Initially, Kendall attempted to solve this problem with the machine’s varispeed controls, adjusting the tape speed manually during playback, or by changing the speed in his DAW. This proved to be extremely time-consuming, however, and in his words, ‘resulted in a large degree of coffee consumption and excessive bad language’.

At this point, Cedar Audio released the Respeed process for its Cedar Cambridge audio workstation. ‘This made it quick and simple to correct the speed throughout each episode’, Kendall reports. ‘Respeed works with speech because it looks at the whole signal, not just things such as the harmonics in notes, or bias tones running throughout the material.

‘Having said that, many of The Navy Lark recordings included a mild and inoffensive mains hum, so it was simplicity itself to instruct the software to ensure that this remained at a constant frequency, and then remove the hum after it had been used as a guide,’ he continues. ‘A problem that before had taken hours to solve was now sorted out in seconds and, on the occasions when the music links played in from disc were carelessly handled – which resulted in the first few notes suffering from wow – a swift tweak of the speed template allowed me to fix the problem. As is the case with Cedar’s other processes, the repair left no trace of itself on the sound, and it wasn’t possible after treatment to hear that the audio had been damaged in the first place.’