Original URL: https://www.theregister.com/2013/11/19/doctor_who_theme_elements_examined/

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

Making music from broadcast test equipment the Radiophonic Workshop way

By Bob Dormon

Posted in Personal Tech, 19th November 2013 16:31 GMT

Doctor Who @ 50 As a theme tune, Ron Grainer’s music for Doctor Who needs no introduction. But to describe this unique piece of electronic music as solely Ron Grainer’s composition would be a disservice to the considerable musical contribution made by Delia Derbyshire, who in 1963 set about realising the original score at the BBC’s Radiophonic Workshop.

Derbyshire’s interpretation of Grainer’s theme had the composer himself questioning his ownership of the piece. The story goes that he asked her, “Did I write that?” to which she replied, “Some of it.” Grainer was expecting a band to have performed his signature tune for Doctor Who. Instead, he heard the distinctive rhythmic canter, haunting melody and menacing hiss – sounds that evoke a sense of mystery and suspense – top and tail each episode.

Grainer’s initial reaction wasn’t necessarily that unusual. All those involved at the Radiophonic Workshop were avidly experimenting with sound, with a great deal of their endeavour focused on creating atmospheres to enhance radio and television productions. It wasn’t all just quirky sound effects for The Goon Show.

BBC Maida Vale Studio

Mildewed wedding cake, anyone? The BBC’s Maida Vale Studios
Source: Google Street View

The BBC’s Maida Vale Studio complex in West London was home to the Radiophonic Workshop, which officially came into existence on 1 April 1958, due in no small part to the persistence of Desmond Briscoe and Daphne Oram, both BBC staffers with a passion for electronic music. Along with other colleagues, they’d been working independently on various commissions and desperately needed an in-house facility to focus their efforts.

Apparently grudgingly, Room 13 was given up for this work at Maida Vale, a former Edwardian roller skating venue, its deteriorating Stucco exterior decor earning the infamous description of being like “a mildewed wedding cake”. Additional workspace was granted (2800ft in total) for what was to become a sandbox for sonic discovery, where these enthusiastic sound artists of their age could work without the restraints of following production protocols. Here, breaking the rules was a matter of course and this was exactly what Delia Derbyshire was drawn to.

Visual records

Before her request for reassignment to the Radiophonic Workshop was permitted in April 1962, Derbyshire had been working at the BBC on the classical music programme Record Review – it’s still going today, though retitled CD Review. As its title implies, it was a show where critics would mull over the latest releases and extracts would be played.

In a 1999 Surface magazine interview, Derbyshire described the work and how one of her many unique talents was able to shine: “One of the music critics would say, ‘Look, it’s on this side of the LP. I don’t know where it is, but it’s where the trombones come in.’ And I’d just hold it up to the light and see the trombones and put the needle down exactly where it was. And they thought it was magic. So a brilliant instinct I must have had. I was appreciated the short time I was a studio manager.”

While both Oram and Derbyshire are now recognised as pioneers in electronic music, undoubtedly the cachet of Derbyshire’s association with the cult of Doctor Who has given greater exposure to her work, albeit retrospectively.

Delia Derbyshire did receive a little direction regarding the fashioning of Ron Grainer’s theme. In Sculptress of Sound, Derbyshire remarks on her commission:

“The first producer of Doctor Who, Verity Lambert, said she had in her mind Les Sculptures Sonores and this group from Paris [Jacques Lasry and Bernard Baschet].

Lasry-Baschet Sound Structures

More than sculptures or instruments: Lasry-Baschet Sound Structures concept art

“Their music sounded really electronic but in fact they were all acoustic instruments and – because the Radiophonic Workshop was a bit ‘below the line’ cost – she came to the Radiophonic Workshop and the boss recommended Ron Grainer because he’d done something called Giants of Steam. Ron saw the provisional titles, as usual – something like a black and white negative – and he took the timings and went away and wrote the score.”

Derbyshire’s Soundhouse interview in 1999 explains her transition from playing records to making them. “I was really happy as a studio manager until I realised that I could move to the Workshop, and before I had even finished asking my boss for a transfer, he had his hand on the telephone.

“It turned out that I was the first person who had actually asked to go there. Previously people had been sent, usually unwillingly, for a six month attachment. I was allowed to stay longer and became the most junior person there, even though I was the most highly qualified.”

Indeed, Derbyshire had a degree in mathematics and music from Girton College, Cambridge, a combination that enabled her to operate the tools of her trade with calculated precision and musical dexterity.

Delia Derbyshire behind the custom built 20-channel mixing desk

Delia Derbyshire at work behind the Radiophonic Workshop’s custom built 20-channel mixing desk. It seems smaller than it is as the majority of its valve circuitry was housed separately in 19in rack units

“I joined in 1962 and the first thing that I did was to go off and tour around our European colleagues’ studios like the ORTF [Office de Radiodiffusion Télévision Française at Radio France] to see how they worked. I was so brave – just marching in like that. It wasn’t long until I returned and began work on Doctor Who. I had only done one other television programme before that called Time On Our Hands, using beautiful abstract electronic sounds. So I was very inexperienced, but making something from nothing was my secret.”

The Art of Noise

In the context of music composition, Derbyshire’s notion of making something from nothing needs closer examination. One could argue that all composers make something out of nothing; crafting ideas into musical arrangements. However, with relatively few exceptions, most are writing with specific instruments in mind. Where Derbyshire and her colleagues excelled was in creating new instruments, often, seemingly, out of nothing.

Radiophonic Workshop 1 equipment bench

Seven Advance N1 signal generators and keying unit. A B&K wobulator is to the right

Indeed, most of the equipment appropriated by the Radiophonic Workshop consisted of signal generators and filters used for BBC engineering work. In short, it was test equipment intended for use to measure the response of circuits: put a sine wave into this piece of radio or TV kit here and see what comes out the other end.

For the broadcast engineers, rather than examine the results audibly, more often than not, the output would be viewed on an oscilloscope to check for signs of distortion, noise and phase artefacts. In many cases, the frequencies being analysed for broadcast purposes were way beyond human hearing.

Hissing with confidence

Furthermore, white noise would be used by the engineers to check the responsiveness of circuits. Again, it was unlikely this would be heard either, as untreated white noise is unpleasant to listen to. Just think of the sound of an old analogue TV without the aerial plugged in and you’re getting close.

Unlike a sine-wave generator, white noise doesn’t have a specific pitch. In fact, it is deliberately random and is designed to contain an equal amount of all the frequency components across the spectrum being examined. Again, for TV and radio use this frequency range would greatly exceed human hearing. So no point in listening to that then.

Well maybe, maybe not. Monitoring the response of audible white noise can be useful in acoustic environments, as it highlights resonant frequencies (a honking or booming emphasis) and damping (typically high frequency loss). A quick blast of white noise (and its colourful cousin pink noise) when monitored in a number of different positions within the room, hall or chamber, can identify the equalisation tweaks required to compensate for the environment’s acoustics.

While this describes how a natural environment can shape the response of white noise, the BBC engineers would also have electronic filters that they could apply to limit or tailor the frequency range being examined, as they went about their business testing and calibrating broadcast and recording equipment.

Filter tips

These filters wouldn’t just have to work on white noise either, any content could be fed through them. Three types of filter are commonly used: low pass, band pass and high pass. So with a high-pass filter, the high frequencies would pass through unfettered and the bass would be attenuated. Just think of a dance music track where the mix transforms to sound like it’s tinny headphone spill and you’ve got an extreme example.

Conversely, with the low-pass filter, the bottom end would be more pronounced as the high frequencies had been rolled off. Again, dance music uses this to good effect when the mix is filtered to sound like it’s just a burble of bass in a club toilet. On individual sounds and instruments, more subtle adjustments to minimise bass with a high-pass filter can be used to make the recording more pronounced in the mix and less muddy. Likewise, the low-pass filter can tame bright recordings so they sound warmer and less brittle.

The band-pass filter is fun too, as it can roll off both high and low frequencies so that you can narrow down to a particular range within the frequency spectrum. A typical example would be recreating the sound of a voice over telephone where both the bass and treble are attenuated leaving a squawky mid-range content. It’s also possible to shift that narrow notch of frequency bandwidth up and down the spectrum, so that interesting sweep effects can be heard. Indeed, this treatment forms the basis of the wah-wah pedal – think Hendrix's Voodoo Child intro [YouTube clip] or repetitive chiming of Massive Attack’s Protection [YouTube clip].

Radiophonic Workshop 1 equipment bench

Room 12, Workshop 2: EMI tape recorders in the foreground with various signal generators at the back

All those examples highlight how the bare bones of simple test equipment can be applied creatively. While a sine wave gives the purest tone, also on hand with the flick of a switch among the various signal generators were harmonically rich square and sawtooth waveforms along with separate white noise apparatus. With these scant resources, the Radiophonic Workshop could begin to make some interesting noises.

More interesting still was the fact that so much of the sound creation was entirely electronic in origin. The cues for “clouds” and “wind bubbles” that Grainer mentioned in his composition notes to coincide with the title visual effects were up to the Radiophonic Workshop to interpret. And so they came about by filtering white noise. Derbyshire didn’t just set up a filter to hiss a bit and leave it there, producing the effect involved a performance element with some carefully timed knob twiddling.

Speech therapy

Radiophonic Workshop gutted piano used for Tardis sound effect

Gutted piano used for Tardis sound effect

Undoubtedly, the Doctor Who theme features some innovative sounds, but the programme itself needed regular sonic sweeteners too: the voice of the Daleks, for instance. This treatment was created by Brian Hodgson using a ring modulator, a circuit that multiplies two incoming signals.

To get the effect, the actor’s voice was modulated by a 30Hz sine wave that, together with the diodes that formed part of the circuitry, produced the menacing warble and distortion of the Daleks. A similar treatment was used for the Cybermen. You can hear how it works, experiment with the controls and find coding info on how to put your own emulator together on the BBC’s prototype page here.

Another example of Brian Hodgson’s brilliance was the sound of the Tardis take-of, created by scraping his front door key along the wound strings of an old piano. Edit, loop, vary speed, and add echo to taste.

The basis of basses

No doubt the precise definition of ‘electronic music’ will be the subject of debate long after the lights go out and the amps are silenced, but not all the sound sources were electronic. Even so, how they were handled was completely different to any conventional performance. Moreover, manipulation by electronic means – either by filtering, modulation or magnetic tape recording techniques – produced unique sounds that couldn’t be recreated by musicians alone.

Delia Derbyshire edits on a Philips EL3503 while Desmond Briscoe checks the script

Delia Derbyshire edits on a Philips EL3503, meanwhile
Desmond Briscoe checks the script

A case in point is the source of the distinctive tum-pet-ti-tum bass line which turns out to be a plucked string. Just how this initial tone was created appears to have been subject to misinterpretation.

One report mentions Derbyshire’s assistant, Dick Mills, as saying she used a blanking panel from a 19in rack unit. It seems plausible as this flexible metal strip could easily be twanged like a ruler on a desk to make a sound that could be varied in pitch. But we shouldn’t jump to conclusions.

Radiophonic archivist Mark Ayres apparently asked Delia personally and she said a plucked string and a rubber band. Incidentally, there are two bass lines – less noticeable is softer more electronic tone that’s somewhat plodding, having longer, sustained notes. That aside, other sources suggest that both the plucked string and the blanking panel were used but not in the way imagined. Apparently a string was tightened across the slightly bendy metal strip, then plucked and the sound recorded.

Breege Brennan’s thesis on Delia Derbyshire’s life and work highlights this method. By contrast, the BBC’s own reporting on the Radiophonic Workshop’s historic sound effects is somewhat ambiguous at first. At the end of the article is a video with Dick Mills pulling out a broken guitar and saying, “People might think we did Doctor Who on this, but we didn’t...”

In the presence of Ayres he then goes on to describe the technique: “It was just one of these strings on a piece of metal channelling that Delia twanged.”

Sampling, Sixties style

One way or another, that’s the initial bassline sound source taken care of, but it was the rudimentary sampling process that followed that really made it distinctive. There are pages and pages online going into the extraordinary detail but in short, the sound was recorded at various pitches. From this, tape loops were created and played to duplicate these tuned sections on another recorder. So Dick and Delia had lengths of tape with different tunings of the plucked notes to draw upon to compile the bass line.

Using well-worn tape splicing techniques – razor blade, edit block, chinagraph pencil and adhesive tape – these bass notes were, in effect, cut and pasted together.

In studios of the time and for years thereafter, tape editing this way was commonplace, but this would typically be on much longer sections. I recall putting together extended mixes by copying off instrumental sections to double the intro, extend a middle eight and or create a percussion break. At 30ips (inches per second), you get a lot of tape to play with as you rock and roll the reels to move the tape slowly over the playback head, listening out for the attack portion of a note or beat to chalk up as the edit point.

Delia Derbyshire plays a tape loop on a Philips EL3503

Editing on a tape recorder was the closest thing to a sampler in those days. Here, Delia Derbyshire plays a tape loop on a Philips EL3503. There were three available that were modified to all play in sync

Judging by the Radiophonic Workshop equipment list that Derbyshire had compiled from her early days there (which appears in her papers here), it seems the fastest they’d have been working at was 15ips and most likely on the Philips EL3503 machines that were favoured. It’s just as well really, as she took to chopping out the notes of the bassline, deliberately truncating them to give a more punchy sound.

Slower speeds would have been more of a challenge and the sections of tape would have been shorter too. Hence greater precision is required when marking up the edits and the smaller pieces of tape can be very fiddly, with sticking tape sometimes overlapping onto the sticking tape of neighbouring edits. Yet for all we know, the Beeb had her run the lot at 3.75ips to save tape.

Tape your time

Anyone can create sounds – whether they’re any good or not is another matter. That said, some sounds only really start to sound interesting when they’re treated with effects. Imagine hearing U2 guitarist The Edge without those dotted ⅛ note delays on his riffs, they’d sound extremely dull if those cascading echoes weren’t there to busy things up. In this YouTube clip he demonstrates his technique.</p?

Tape loop echo configuration

Tape loop echo configuration with two machines

Likewise, the whooping synth noises in the Doctor Who theme would lack atmosphere without those supporting echoes that repeat its strange electronic tones, adding a sense of spaciousness to the melody line’s impact. With no sampling to create digital delay lines, the effect was created using a tape loop that could be fed through several tape machines. The initial recording would then be replayed over multiple tape heads, the spacing between them creating the delay time. The timing of the echoes could be varied by simply changing the tape speed.

Dedicated tape loop echo units did exist at the time, such as the Watkins Copicat, but the Radiophonic Workshop’s grow-your-own method and almost certainly delivered a higher fidelity effect. Moreover, the tape machines were frequently used as an effect, with simple changes such as reversing a tape or changing its speed producing useful results.

The splice is right

Splice editing required skill and, in the right hands, was an art in itself. At the time, cloning and chopping up tape was the closest anyone could get to the sampling tools we have on our phones, desktops and in studios today.

Delia Derbyshire edits on a Philips EL3503

With three tapes running in sync, edit lengths had to be precise
to keep it all in time

Yet even Derbyshire and Mills were caught out here. They compiled the theme on three separate reels of tape simultaneously played in sync from three reel-to-reel tape machines. As this was all coming together they noticed a timing issue. Although the adhesive edit tape was visible on the tape backing revealing each splice, it would just fly by as the tape wound on and as a visual cue was effectively a blur.

Unable to trace the issue during playback, the two set about another method of detection and decided to roll out the three tapes alongside each other down the long corridors of the Maida Vale studios. They knew that it must be a flawed edit, where one section was fractionally longer than the other two tapes. Yet this laborious compare and contrast approach worked, as they checked the splices and the errant extended edit was located and cut to size.

Incidentally, if you peruse the equipment list you’ll notice a multi-track recorder was available, which begs the question, why bother with this three tape palaver? Derbyshire tells it like it is in her Radiophonic Ladies interview with Jo Hutton for the Sonic Arts Network in 2000, the year before her death.

“We had one Leevers-Rich eight-track machine which was a bit of a white elephant. It was an expensive variable speed eight-track machine on one-inch tape but it wasn’t very good sound quality.”

Unsurprisingly, Derbyshire preferred a higher quality alternative.

“We had three remote-controlled, synchronised Phillips tape recorders. This changed the whole of our work because before that, not only did the machines not run at the same speed as each other, but the rulers that we had read differently. There was one wooden metre ruler and a plastic 12-inch ruler and so, if one was doing intricate work, nothing would sync at all.” Yes, those tape sections for the bassline – and other parts where timing was critical – were all made to measure.

Calculated riffs

Musical timing wasn’t the only factor that needed to be attended to: having these disparate elements play in tune was crucial in piecing together a listenable theme tune. Using an electric organ would be too recognisable and would bypass the experimental raison d’être of the facility and its musique concrète convictions.

Brian Hodgson and keying unit with 12 Jason oscillators

Brian Hodgson observes a frequency counter (right) as he fingers the compact decay-only keying unit connected to 12 Jason oscillators, three are obscured by equipment. Note the wobulator to the left

As synthesisers weren’t something you could buy off-the-shelf in those days, electronically generated sounds needed to be tuned manually. The Radiophonic Workshop did have a makeshift keyboard that used parts from a piano. It was described as a “keying unit” because it didn’t actually send out any pitch information.

The piano octave layout was for convenience, as it was merely a triggering device that could fire off individual tone generators, as Derbyshire explains: “There were 12 Jason valve oscillators, with eight electronic gating circuits, built in-house. The accurate oscillator was a Muirhead, which is used in research equipment. It was a switchable one used mainly for tuning, whereas the Jason was just swoopy – you know, Doctor Who swoopy.”

In synthesis, the gating refers to the switching on and off of the signal to vary its output duration. It’s something a musician would instinctively do by simply keying the note. Back then, things weren’t that simple, something Derbyshire was keenly aware of.

Delia Derbyshire tweaks a Jason oscillator

Sound artist: Delia Derbyshire tweaks a Jason oscillator

“Of course now on the computer, one can tune in any sort of scale by just pressing a button, but at the time I used to work it all out with my log tables, like the Pythagorean scale, the mean tone scale, adjust tuning and I remember doing a whole lot of comparative tables for Ron Grainer. I did the Doctor Who theme music mostly on the Jason valve oscillators.”

The hall effect

Arguably a more subtle effect than delay or echo is to apply reverberation to enable different instruments and treatments sounds like they occupy the same space together. Reverb comprises of countless, short echoes that can take a while to fade, giving rooms, halls and cathedrals their unique ambience.

EMT 140 plate reverb unit

The damper in the EMT 140 was as big as the plate itself

Acoustic chambers can be used – where sound is played from a speaker to be picked up from a microphone – and the reflections of the room are the effect that’s returned to the mixing desk. The BBC did have such facilities too.

However, a seemingly more compact option for the time was the EMT 140 plate reverb. It featured a 0.5mm thick metal plate (approximately 1m x 2m) suspended in a metal frame and housed in a wooden box about 8ft long and 4ft high and 1ft wide. It weighed over 400lbs.

Slap the side of a typical van and what do you hear? A bit of a boom, right? Do the same on a car roof and the effect is more shortlived. That’s how the plate reverb worked. With a transducer much like a loudspeaker mounted in the centre of the plate, audio was played into the metal. A microphone-style transducer (two for stereo) positioned outside the plate would pick up the sound vibrations and return the signal to the mixing desk.

EMT 140 plate reverb controller

EMT 140 plate reverb remote controller

A damping function was available too, that would vary the decay of the plate reverb effect. Apart from the level driving the plate reverb from the mixing console, the damper was the only effect variation available and it had its own remote control.

This remote would sit on the mixing desk (or as a module inside it) and what was displayed as a reverb time meter reading would actually drive a motor to change the position of the damper when you pressed one of two buttons for more or less. In my own experience with the EMT plate reverb, it was the motor that was always failing, so you’d end up stuck with just one reverb time until it was serviced. Great sound though.

Dialling in a performance

The Muirhead that Derbyshire namechecks was a Muirhead-Wigan D-690 decade oscillator. It was more precise because the desired frequency could be generated by clicking through an array of rotary switches for multiples of thousands, hundreds, tens and units of frequency.

Muirhead-Wigan decade oscillator

Precision instrument: Muirhead-Wigan decade oscillator

This would be ideal for those tuning calculations Derbyshire would make to determine the correct pitch of musical notes. Muirhead made a sine wave to square wave converter that was also used at the Radiophonic Workshop. A later more sophisticated model can be viewed here.

Tuning using the Jason oscillators was a matter of twirling a dial with just a frequency scale to line it up with to get the approximate pitch. Again, there was an art to making these scientific instruments sound like musical instruments. Frequency counters could also be used to aid accuracy – routine equipment for the broadcast engineer – and at the time these measurements were quoted as cycles per second, later becoming standardised as Hertz. The performance aspect was also enhanced by modifications to the keying unit, akin to features that would later become standard waveform envelope-shaping features adorning synthesisers.

Keying unit with decay-only function

This eight-trigger keying unit is an early version, being equipped with a decay-only envelope function. The shape of this keying unit suggests this was model was later modified to feature the attack circuitry

According to the BBC’s own Monograph in-house publication from January 1963, two keying units were constructed at that time. One would drive seven Advance N1 valve signal generators and the other was rigged up to the 12 Jason oscillators Delia mentions.

However, Monograph documents the original unit as having 12 keying circuits that would simply switch on the different signal generators and yet could vary the decay time (fade out) for each of these notes. A later, eight-switch version appeared that could alter the attack (rising) aspect of the signal too, as well as the decay. In effect, working as a voltage-controlled amplifier (VCA).

Keying unit with attack and decay function knobs and switches

Attack and decay functions appear on this later modification
which is linked to a bank of Advance N1 valve oscillators

A number of photographs show this later version hooked up to the Advance N1 signal generators, yet Derbyshire’s recollection suggests she nabbed the more expressive eight-key version, even if it did mean potentially losing four notes.

That said, these custom-made keying units did go through several stages of development and equipment could be moved around easily enough, although Derbyshire is only seen in photos using the more compact “first attempt” 12-trigger unit together with an array of Jason oscillators.

Indeed, it’s also possible that she used the Advance N1 units that were housed in Workshop 1 (Room 13). However, the 12 Jason signal generators she refers to were found in Workshop 2 (Room 12) which was better known as Delia’s Room.

Delia’s Darlings

Delia Darlings group logo

If you’ve never heard of Delia Derbyshire, then it’s not exactly surprising as Ron Grainer’s name was all that appeared on the credits of Doctor Who, along with the Radiophonic Workshop. Admittedly, he did compose the piece but he recognised Derbyshire’s astonishing interpretation of the work and offered her half of the royalties.

“The BBC wouldn’t allow it,” said Derbyshire in her Radiophonic Ladies interview with sound artist Jo Hutton. “I was just on an assistant studio manager’s salary and that was it... and we got a free Radio Times. The boss wouldn’t let anybody have any sort of credit.”

As the staying goes, ‘art will out’, and recognition for her achievements couldn’t be obscured indefinitely. The 1968 album An Electric Storm with David Vorhaus and Brian Hodgson under the name White Noise, showcased their studio craft with songs featuring sonic soundscapes that were way ahead of their time.

White Noise: An Electric Storm album cover

With the release of compilations of Derbyshire’s solo pioneering studio compositions, her work has captured the imagination of experimental composers, academics and electronic music enthusiasts. This year saw Delia Derbyshire Day and a number of other events organised by Manchester-based music collective, Delia Darlings, that paid tribute to her considerable musical output.

The location of Delia Darlings should come as no great surprise. The University of Manchester is trustee of Delia’s works and papers, including 267 tapes from the Radiophonic Workshop and her various independent projects. Two departments, NOVARS and the Centre for Screen Studies have catalogued her work and digitised the audio content enabling access for future research.

The Delian Mode DVD cover

Besides the various Radiophonic Workshop programmes that the BBC runs from time to time, such as Alchemists of Sound, Sculptress of Sound and Wee Have Also Sound Houses, is a short independent film The Delian Mode – an intriguing collage of audio and visual clips made by Canadian director Kara Blake.

According to the exhaustive WikiDelia, Kara Blake had put in a request to feature a sample of the Doctor Who theme in The Delian Mode, and was quoted $1000 per second by the BBC. Talk about making something out of nothing.

Delia Derbyshire's celebrated green lampshade

Early on in her 11 years at the Radiophonic Workshop, Delia Derbyshire discovered that the chime of a green metal lampshade proved to be a significant resource for sound sculpting. By eliminating the attack portion of the sound it made, she emphasised its sonorous mystique, fashioning envelopes with fades, which, together speed changes, created a haunting air.

A ‘found object’ of the musique concrète ilk that would eventually end up on display at the Science Museum, reams have been written about the green lampshade. Delia’s composition Blue Veils and Golden Sands being the most notable example of its atmospheric tones – YouTube audio here. This title would also grace an entertaining biographical BBC radio drama first broadcast in 2008 and occasionally repeated on BBC Radio 4 Extra.

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.