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| Here, we look at the dramatic control panels and the music control
desks. |
THE DRAMATIC CONTROL PANELS
Although Dramatic Control Panels were by present day standards extremely simple passive mixers, it is very difficult today to work out accurately how they were used and by whom. Part of the problem is that with the outbreak of W.W.II and the economies that had to be made, the DCPs ceased to be used and were probably quickly dismantled. The result was that even people who joined the BBC in the early 1940s only know of them from brief references in books such as the 'Engineering Division Training Manual - 1942'.
Some clues about how the DCPs were used can be gleaned from the film that was made of Val Gielgud and Holt Marvell's 1934 novel 'Death at Broadcasting House'. Val Gielgud was Director of Productions and played the producer in the film. Holt Marvell was the pseudonym of Eric Maschwitz who was Head of Variety at the time. There are shots of Val Gielgud at what looks to be a very accurate mock-up of a DCP as well as generally very realistic reconstructions of the productions group studios in Broadcasting House.
It has been shown a couple of times on TV and is well worth a look if it's
ever shown again. The film, and other evidence, suggests that Gielgud preferred
to have an engineer at the controls, but some other producers preferred
to operate the desk themselves. left - Val Gielgud (foreground) at the DCP. This appears to be the real thing, not a shot from the film.
Two Quotes from the 1940s:
Engineering Division Training Manual - 1942:In the years that broadcasting has progressed, producers have become more and more ambitious. For certain shows they demand very many more studios than can be accommodated on the four-channel source mixer provided in the Control Room. So an additional multi-channel mixer, known as a 'production panel', which can have the outputs of the 'A' amplifiers of anything up to 12 or 15 studios connected to it, has been devised. At this panel the producer sits and directs his programme in such a way as to obtain the correct continuity; the final output being fed to the source selector (in the Control Room) on one pair of wires.It is interesting here that the name 'production panel' is used rather than 'dramatic control panel'. This probably came about due to use being made of them by programmes other than Drama productions. Although dated 1942, quite a lot of this manual seems to be based on pre-war practice. In an appendix at the end of the book there is an extract of an address given by Assistant Controller (Engineering), H. Bishop, to the IEE and printed in the IEE Journal in January 1942:
There was a tendency in peacetime for broadcasts to become technically over-elaborate. The use of a number of studios for one production was a growing habit which was catered for to a maximum of 15 channels by a somewhat complicated mixing and control unit known as a "productions panel". With the introduction of local control and the use of larger studios, this multi-studio tendency has largely disappeared and the engineering problems associated with big productions have correspondingly lessened. In any case, the stringencies of wartime broadcasting make such economies essential both as regards accommodation and equipment.This rather gives the impression that even pre-war production ambitions were not totally approved of by the engineering department!
So Why Were Dramatic Control Panels Used?
The simple answer is so that scenes that were supposed to be taking place in different acoustics actually sounded different which meant using different studios for reasons explained below. Also some plays involved an orchestra and chorus and it was not practical to have them in the same studio as the actors, nor was pre-recording an option. (Although two Blattnerphone steel tape recorders were installed on the seventh floor of Broadcasting House when the building entered service in May 1932, they were totally unsuitable for music recording as the speed was not stable. The operator, while watching a stroboscope, had to manually regulate the tape speed.)It had been realised in 1926 that 'perspective' was important. For example if a play calls for one actor to walk out of a room, then that actor needs to actually walk away from the microphone. If the microphone is simply faded down, the result will not be convincing. The trouble was that studios were in many cases acoustically dead (such as those intended for speech and the effects studios) and those that weren't 'dead' were uniformly treated with sound absorbent material so 'perspective' was very difficult to achieve.
No doubt due to its limited range of acoustics, it was said that the 1932 6A was always recognisable as 6A whether it was supposed to a baronial hall, a living room or a law court. Another problem was that the microphones in use, mainly Marconi-Reisz carbon microphones, were virtually omni-directional except at the higher frequencies, so there was no 'dead' side, which again made it difficult to achieve perspective. In addition even very large studios had a limited number of microphones. For example, 6A which was 36 feet long and 16 feet wide had just 3 independent microphones even though it was used for the musical parts of drama productions and 'concert parties' as well as speech.
The intention was that reverberation could be added as required to produce a different acoustic and there were 5 echo rooms available for this purpose. Without the use of a DCP echo could only be added by the control position engineer in the Control Room. (BBC usage has always been to use the word 'echo' when what is meant is 'reverberation'). This of course meant it was not under the control of the production staff who were responsible for the 'balance' and left to the judgement of the engineer who was only supposed to be responsible for 'control'.
There were 10 studios on the sixth and seventh floors in the so-called 'Productions Group' mainly devoted to drama. The major studio was 6A and its associated dedicated speech studio 7A. 6B, 6C, 7B and 7C were used for speech, 6D and 7D were effects studios complete with water tanks and the other usual effects paraphernalia, 6E and 7E were used solely for gramophone effects and incidental music. (6C, 6D, 7A, 7C and 7D had a totally dead acoustic). These studios were more or less always used in association with the two DCPs and this allowed for one production to be on transmission and another in rehearsal or indeed the simultaneous production of two independent plays.
A Technical Description of the Dramatic Control Panels
There were two Dramatic Control Rooms situated on the north-west corner
of the 8th floor opposite the doors leading to the rehearsal section of
the Control Room. Both were wired so that they could be used either for
rehearsals or transmissions.
The equipment of the D.C. Rooms consisted of the usual red transmission
and blue rehearsal lights and an indicator for return cue lights operated
from those studios where orchestras were likely to play in conjunction
with dramatic productions. These return cue lights were provided so that
the staff in the Dramatic Control Room could be given a cue at the end
of a piece of music and the indicator panel can be seen fixed to the wall
at the top left of the photograph.
There was a loudspeaker; a telephone for communication with the Control
Room; a microphone for giving instructions to artists during the progress
of a rehearsal and the dramatic control panel itself.
The 'A' amplifier outputs of the studios required for a production were
plugged to the DCP channel inputs in the Control Room at a bay adjacent
to the 'A' amplifier bays. It seems likely the engineer plugging up the
studios to the DCP would at the same time have switched on the 'A' amplifiers
by operating the keys provided on the 'A' amplifier bay. The echo room
inputs and outputs were on the same bay as the DCP inputs so any echo
facilities needed were easily plugged up. An echo room was fed from a
second output on each 'A' amplifier and the echo return was plugged to
the fader on the extreme right of the desk.
Each
dramatic control unit had eleven inputs. Ten of the inputs, each controlled
by a separate potentiometer, were divided into two groups of five and
controlled by a 'fade unit' or group mixer. The 'fade unit' consisted
of a potentiometer that faded out one group of five inputs and faded in
the other group when turned through 180 degrees with both groups being
at their full volume with the potentiometer midway. The output from this
fade unit was connected to one of the inputs of another similar fade unit
or two-way mixer, the eleventh source of programme being connected to
the second input of this latter fade unit. This was to allow for cases
where one studio was used for such items as speech, which may predominate
in a dramatic production, and it was claimed that a much quicker and easier
fade was available to and from the effects required to be superimposed
on the speech. This type of fader seemed to have been very popular in
the 1930s but disappeared without trace at the outbreak of war. Mixing
was of course entirely passive. The inputs were at -18dBu and although
nothing is known about the configuration of the faders there was room
for up to 50dB mixing loss so that the DCP output arrived in the Control
Room at -68dBu, that is at the same level as other sources.
During rehearsals the producer could speak to all the artists in the studios
via loudspeakers and, during transmissions, to the production staff responsible
for the studios by means of headphones. Facilities were also provided
for artists to listen to the progress of the production while the studio
in which they were situated was not actually faded up. There were back-stop
contacts on the faders that were said to operate relays that cut the programme
to studio loudspeaker. It is not certain how this was achieved since normally
a studio loudspeaker was fed from the Control Room via a trap valve amplifier
which must have been plugged up as required as there does not appear to
have been any relay switching involved. One possible solution would be
that relay contacts could be plugged between the output of the trap valve
and the line to the studio loudspeaker and perhaps each DCP input had
a 'loudspeaker cut' pair of jacks associated with it to be plugged as
required.
In the photograph of the DCP the two groups of 5 input faders can be clearly
seen. Between them in the centre of the desk are the group fade unit and
the 'two way mixer' which faded between the eleventh source and the other
ten. The row of keys below the faders are green cue light keys to the
studios. 
Above
the faders are small circular recesses containing lamps. Caps were provided
which were engraved with the various studio names. An engineer put the
appropriate caps into the recesses to identify which studio was on each
fader. The lamps would light when control room plugged the studios to
the DCP. A small red lamp immediately above each cap lit when the fader
was moved from the off position.
The cluster of keys on the left may have been prehear/talkback keys, or
perhaps red or blue light keys; the circular object in the left hand corner
of the panel is a headphone jack. From the 'Death at Broadcasting House'
film it seems certain that the key under the echo fader at the far right
is the producers talkback as Val Gielgud is seen operating it in the film
and asking the desk operator to fade up a studio so that he could hear
the reply. To the right of this talkback key is a headphone jack; the
purpose of what looks like a rotary switch above it is uncertain.
At first glance the DCP seems very simple and the programme chain itself
is simple, but when the ancillaries such as talkback, loudspeaker feeds,
cue lights etc. let alone red light switching and how the engaged lamps
were lit in the Control Room are considered then Edward Pawley's comment
becomes more understandable:
It was technically very complicated; once it was set up on transmission, it was impossible to locate faults. The use of many studios on one production meant that staff were dispersed on three or more floors, and it was necessary to have 'studio managers' (in the theatre sense) to keep track of artists and to make sure, not only that they reacted to the right cue light but that they were in the right studio. There was no control of dynamic range on the dramatic control panel, so again there was the problem of the engineer in the control room neutralising the intentions of the dramatic control panel operator.However this is not totally correct because in the book "A Technical Description of Broadcasting House" it says:
The dramatic control unit in D.C. Room No. 1 is equipped additionally with a main control potentiometer, whereby a producer can, if he wishes, have another official controlling the final output volume actually in the D.C. room; otherwise programmes are controlled at the control positions in the Control Room, or at the cubicle control desks.
Documentary
film footage shows that this main control and a programme meter were set
into the rear of the desk, a detail copied on the mock-up desk used in
the film 'Death at Broadcasting House'.
This photo (probably not taken in 1932, but no later than 1936) shows
a rear view of the desk being maintained and clearly shows the meter on
the right edge of the picture. The main control can also be seen, though
partly obscured by the object in the foreground. The next photo, which
dates from 1937, suggests that the main control and meter were later resited
in the box on the left of the panel.
Later developments
In
1934 a very large drama control panel was built in Broadcasting House. It
was originally intended for controlling the multi-source programme in connection
with the King's 1934 Christmas Message. Edward Pawley says it was 'so large
that it had a 5-ft bench seat on a little trolley so that the operator could
ride quickly from one end to the other to reach the control knobs.' This
does seem to be an unlikely story unless the desk was radically different
from the 11 channel DCP. The illustration is from an Ogden's cigarette card
of 1935 and presumably shows this later desk. Hard to tell if the operator
is sitting on a trolley!THE MUSIC CONTROL PANELS
On
the seventh floor were four cubicles containing mixers. Two of these were
associated with two of the transmission control positions in the Control
Room (numbers 1 and 2), and the other two with two of the rehearsal positions
(7 and 9). The rooms were acoustically treated and were provided with loud-speakers
for monitoring. They were used for controlling 'important' music programmes
and were operated by musically qualified staff. The first illustration is
another 1935 cigarette card.
The
desk was fitted with a four-channel fade unit, a main level control, a programme
meter and studio red and green light keys. A telephone to the Control Room
was also provided.The corresponding desks in Control Room had just four faders, and these music panels should be operationally similar. So perhaps the fifth fader shown in this shot is an echo return, similar to the fader at the right of the DCPs? Another possibility is that this desk had separate faders for each source, rather than the cross-fading system used on the Control Room desks. This would seem to be a better arrangement for controlling music programmes.
The cubicles were switched into circuit by the engineer at the associated CR control position, who was also responsible for selecting the required sources to the channels. A key on the control position operated the cubicle change-over relays. Four of these disconnected the selected sources from the control position and connected them to the inputs of the cubicle mixer. A fifth relay disconnected the output of the control position from its B amplifier, and connected instead the output of the cubicle mixer.
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