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Delia and the Doctor: How to cook up a tune for a Time Lord

Making music from broadcast test equipment the Radiophonic Workshop way

Beat this

A solitary sine-wave generator made by Airmec gets a mention on the spec list but appears be one of those things they had lying around, rather than a particular favourite. Talking of favourites, the curiously named wobulator certainly had its admirers.

Taking a turn on the Airmec sine wave signal generator

Taking a turn on the Airmec sine wave signal generator

To give you an idea of what it could do, the BBC has even knocked up an online emulator, which just like the old days, may or may not work reliably – it’s all dependent on your browser apparently. I gave it a twirl in Safari, which was good while it lasted. Google's Chrome is best says the Beeb and, in my experience, that is indeed the case, just refresh the page if it’s unresponsive and don’t forget to turn it on.

Daphne Oram with a B&K wobulator

Daphne Oram with a Brüel & Kjaer wobulator

Technically, the wobulator was a Beat Frequency Oscillator (BFO) and the model used by Derbyshire and co. was a Brüel and Kjaer (B&K), which was quite a sizeable valve beastie with a tuning scale that dominated the front panel.

The smaller B&K Type 1022 is often mentioned but isn’t quite the same model, although it has similar functions. Besides scientific instruments and measuring equipment, the Danish but British-owned Brüel and Kjaer makes exceptionally accurate, high quality microphones.

Back in the day, BFOs were common among amateur radio (Ham) enthusiasts, enabling them to hear morse code radio transmissions. How this worked was to closely match the incoming radio frequency with that generated by the BFO and mix the output.

The radio frequency was too high to be audible, but by using BFO equipment and mixing the continuous wave (CW) broadcast being received with a generated signal that you would tune in, the two signals would beat together. An audible output – the beat frequency – would result, it being the difference between the frequency of the CW transmission and that matching frequency generated by the BFO.

Youtube Video

Still with me? OK, take a look at the YouTube video above and you’ll get the idea. Incidentally, BFO circuits are also widely used in metal detectors, using differences in responses to the radio waves generated and received to give an audible indication of the presence of objects... or not. There’s a fuller explanation here.

Radio hams and treasure hunters aside, the BFO could be used to perform perfectly timed modulation effects on audio signals too and, in doing so, lived up to its wobulator name. Have a play with the Beeb’s emulator and you’ll find out for yourself.

Console commands

Naturally, all these disparate sounds needed to be channelled somehow for recording and playback. For this purpose, Room 12 ended up with a custom-made mixing console that was built by BBC engineers and featured 20 channels in total. It also featured dials labelled Programme Effects Unit (PEU).

Radiophonic Workshop 20-channel mixer

The Radiophonic Workshop’s 20-channel mixer with its four PEU controls (top left)

This somewhat misleading description refers to the passive equalisation circuitry that performed the high- and low-pass filtering tasks akin to those described earlier. When it came to time delay effects, such as echo and reverb, these would be provided by outboard gear rigged to the mixer. What was available is covered more detail in ‘The Hall Effect’ and ‘Tape Your Time’ box sections above.

In Room 11, an editing facility, was a 12-channel transistorised console designed by Johnny Longden which had previously been used for outside broadcast.

Over time the consoles were modified but the most notable change in the early days was the implementation of the Glowpot fader. This optical arrangement using lamps and light dependent resistors was designed by Dave Young whose unique character and engineering achievements are described affectionately in more detail on The White Files website.

Radiophonic Workshop 12-channel Longden mixer

The 12-channel Longden mixer was modified with Glowpot technology from the outset

The need for this modification was to enable smoother control of the mixer volume levels as the quadrant faders fitted to most BBC consoles were susceptible to ‘stud noise’ – having an action much like the rotary knobs on the console – with each click changing the resistance and delivering a 2dB shift in level. The Glowpot fader smoothed all this out avoiding unwanted noise during level changes.

This was certainly to be welcomed in order to seamlessly fade in and out various elements of the Doctor Who theme, as they were prepared on those three tapes, each of which comprised submixes. By submixing, you’re able to group together specific parts in one recording, and prepare aspects of the arrangement, so it’s not a scramble with all hands on desk as it plays.

When it came to mix down, Derbyshire and Mills had all the basses on one tape, the swoops and melodies on a second reel, and the bubble and his effects assembled on the third one. All three tapes were then played simultaneously and mixed together to be recorded as a final mix on another tape machine, whilst adding further volume changes and effects, as desired.

Youtube Video

A breakdown of the various sounds that were created for the Doctor Who theme are examined individually in this extract from the 2003 BBC documentary Alchemists of Sound

The result: a futuristic yet timeless theme tune utterly fitting for sci-fi series and even more fitting for a Time Lord who’s been a part of British telly for five decades. There are so many versions of the theme now that it would take another feature in itself to trawl through them all, and some really aren’t worth the bother, being the sonic equivalent of drawing a moustache on the Mona Lisa. From Derbyshire’s earlier remarks, she obviously thought that it was nigh on perfect and didn’t need “tarting up” and the evidence suggests she wasn’t wrong either.

As Delia Derbyshire said herself, making something out of nothing was her secret. Looking back on the resources of the Radiophonic Workshop in those times, there’s no doubt that she was a master at it. Through her work on radio and television, she brought new and exciting soundscapes to our ears and a theme tune recording that, 50 years on, remains etched upon our nation’s consciousness. ®

Thanks to Ray White for the archive images from various sources including the BBC on The White Files.

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