For a new recording of Handel's Messiah, Stephen Cleobury enlisted a secret weapon to defeat the reverberation of King's College Chapel - The Decca digital mixer. His only mistake was to neglect the show business motto - never work with children... or head gardeners

The new Messiah? No, this was never going to be another false dawn. This new recording would feature an exciting lineup of young soloists, the choir of King's College Cambridge and an excellent original-instrument orchestra. Put all these ingredients together in the beautiful setting of King's chapel, and the results should be as satisfying a musical feast as one could hope for.

But equally important as the musical excellence of any new recording is the technical aspect. Our challenge was to present the work in an immediate and realistic way, and at the same time capture the magical acoustic of the chapel. This was our self-imposed brief, but little did we know of the obstacles that would present themselves to us - the virus that lay in store, and the newly-laid grass to mention but two!

Contrary to popular myth, the acoustic of the chapel of King's College is actually a positive asset for recordings, something to be embraced rather than avoided. It is falsely assumed that its generous reverb helps conceal any untidiness within the choral or orchestral extreme, but in fact because it is such a clean acoustic, it is also merciless in revealing even the most minuscule lack of ensemble playing.

Wired for sound

In an ideal world we would have used two microphones only for this recording. But given the distance from the front of the orchestra to the back of the choir, to achieve an equal balance the mics would have had to have been placed so far away from either group as to lose presence on both choir and orchestra. The overall effect would have been pleasant enough, but ultimately unsatisfactory, as there would have been too great a ratio of chapel acoustic to direct sound. The feeling is rather like walking into chapel after a service has begun: the wash of sound is lovely, but after a few minutes of listening under these conditions, one wants to get nearer to the heart of the music and actually feel more in contact with it.

So instead we were looking at a multi-microphone technique. We normally use omnidirectional microphones (type Neuman M50) for the main pick-up on the orchestra. As their omnidirectional description implies, they hear sound from all around them - orchestra, ambience and to a lesser extent whatever other sounds are being created. Another set of mics will be in front of the choir. These will normally be directional. In other words they hear the sound of the choir, but tend to exclude other orchestra mics. To achieve a credible balance and create a relative perspective is a tall order.

The time taken for the choir's sound to be picked up by their own mics is infinitesimally small, but the time taken for the sound of the choir to travel to the omni-directional mics at the front of the orchestra is significantly and measurably greater. This time can be precisely calculated by measuring the distance from the choir to orchestra mics; knowing that sound travels at one foot per milli-second, it is easy to appreciate that there will be a delay. When these two sets of mics are mixed together there will be a small but perceptible smearing of the sound. For instance, consonants will appear to have a double attack - even assuming that the choir is absolutely together! This is one important reason why 'purists' do not favour the use of lots of microphones.

Since the mid eighties, Decca has had its own time-compensation system built in to its digital mixer. We wanted such a system of "time-aligned microphones" to ensure that our recording of "Messiah" would be technically head-and-shoulders above the rest. The problem is that the Decca digital mixer is not portable - how could we bridge the sixty-two mile gap between Cambridge and London? Our cables weren't that long! The solution was simple, but the logistics, as you will see, were not.

The answer was to record each microphone onto its own track of a digital multi-track recorder. After the recordings were complete, we would play it back through the digital mixer with the correct time-alignment. For the purposes of the recording sessions, we used an analogue mixer solely to monitor our work. Thus we could play back to the artists, and the balance and perspectives could be ascertained.

Once this was achieved, the mixer settings were logged, so that they could be transposed onto the digital mixer for the final mix. In this way, the conductor and artists would be confident that the sound and balance they were hearing for session playback would not be altered. The only difference that they should be aware of, is that the new digital mix would be substantially cleaner and more accurate sounding. Because of this enhanced clarity, it would be possible to include more of the King's acoustic in the mix. So now, we would have the benefit of both presence (being in touch with the music), and ambience (being aware of which building you are in).

A point of orchestral layout is worth a brief mention here. In accordance with performing practice at the time, the first and second violins were split, left and right respectively. The trumpets and timpani, however, we placed behind the conductor facing the rest of the orchestra.

"We wanted such a system of 'time-aligned microphone' to ensure that our recording of 'Messiah' would be technically head-and-shoulders above the rest."

This solved two problems in one fell swoop: Firstly, they would not need their own mics as their sound would be amply picked up by the main orchestra mics. Secondly and more importantly, by removing them from the back of the orchestra, their sound would no longer impinge on the choir mics, and the back of the orchestra and choir would be closed, thus making for a much more integrated set-up and better musical contact for all the performers. Also there would be a reduction in the amount of electronic 'massaging' that would be necessary for the time-alignment.

Illogical logistics

It isn't long before logistical problems really started to rear their ugly heads. For our control room at King's, the Director of Music allows us to use his office. It is large enough to accommodate, on top of all our recording equipment, orchestral musicians and singers for playbacks. But the multitrack recording machines are bulky, with noisy fans to keep them cool. We would ideally have placed them in a small room at the back of the main office.

For security, we always run two recording machines. Should there be a drop-out or fault on one tape-machine, the chances are that the other will be perfectly all right. It was apparent very early on in the planning of this recording, that two large multi-track recorders would not fit into this room. To have run them on the landing outside the main office would have obstructed a possible fire escape route. Plan B emerged: we would have to house them in their own van.

The logical place to park this van would have been at the end of the building that housed the control-room. There was no problem supplying mains and audio feeds to and from this position, but there was a problem with the permissible length of cable that handles the metering and remote-control information. The proposed distance exceeded the length which was necessary to guarantee reliable control over the machines.

Plan C was to park the van outside the back room window. We could either park on the stone pathway, or on a narrow strip of grass. We would have to approach the college for advice and permission. Parking on the pathway was definitely not on. It would have forced members of the college and the public onto the college lawn, a square of hallowed turf reserved for fellows of the college. In the end, the college reluctantly gave permission for us to park on the grass strip directly outside the window. They were even kind enough to provide us with wooden planks on which to park the van for the three days of recording. Very gingerly, the van was driven with great precision onto these planks and parked right outside the window. Everything was connected up. "Messiah", King's style was under way!

The recordings were scheduled to take place over two periods: three days in December 1992, and three days in March 1993.

Precise measurements would have to be taken of microphone positions, heights and pre-set gains after the December recordings, so that we would be able to match the sound exactly for the completion of the project in March.

"Waiting for the reverberation to die away at the end of a take before spewing up is the height of professionalism."

Te deum ad nauseum

During the December recordings a virulent tummy bug was going round the choir school. Its effects were quite volcanic. We had just done the first take of 'Since By Man Came Death' when the half-time break came in the recording session. Two of the senior choristers came back to the control-room, not for the playback, as one might justly have assumed, but to complain that they were feeling unwell. Indeed, one boy did look a particularly peculiar shade of green. Both the producer and director of music explained that there were times in life when, however awful one felt, the show simply had to go on. This was a vital chorus, and it would be greatly appreciated if they could make a big effort.

Without a murmur, both boys realised that true professionalism was called for, and returned to the chapel for the resumption of the session. The take number was announced and the music began. The last chord of the chorus sounded, with not a single rustling of vocal scores as the five seconds of reverberation died away. A few more seconds of silence followed, as the producer pushed his talkback button to congratulate the choir and orchestra for a splendid take.

At that precise moment Mount Vesuvius erupted, in the form of senior chorister Ben Griffiths. Both retching and ensuing cascade (with five seconds of reverberation) were digitally captured. Yes, the tape machines were still running (in sympathy, no doubt). Could this be the first digital recording to exceed twenty-four bits? (diced carrots, was it - Ed). It has to be said that waiting for the reverberation to die away at the end of a take before being ill is professionalism of the highest order. Roy Goodman, who was leading the orchestra, reminded us of a similar incident when he was a chorister in the choir. On that occasion, it actually took place in the middle of a take, and he overheard one of the orchestral musicians leaning across to a colleague and saying "fair comment"!

In spite of illness, the first batch of recordings finished well. It must have been a nightmare for Stephen Cleobury. After our recordings, the choir was due (amongst other commitments) to make a television recording of the Nine Lessons and Carols for the BBC, there was also a major Festival Hall concert and, of course, the live broadcast on Christmas Eve. Viruses obviously have no sense of occasion.

Turfed out

Christmas came and went. The concluding sessions were looming, and it would be necessary to speak to the Clerk of the Works at King's to renew our request to park our van on the grass. When contacted, we were told this was now completely out of the question. The reason given was that in December we had damaged the edge of the grass strip where the van mounted the planks. To make matters worse, new turf had been laid throughout the college, and the prospect of three tons of vehicle sitting on it for four days was unthinkable.

We pleaded with them, explaining our technical problems and the fact that this was a continuation of what had been started last December. King's were not happy. We then suggested that we could build up the planks at the edge of the grass, so that the van would not have a destructive effect. We were referred to the head grounds man, who was very sympathetic. It transpired that a previous head groundsman lost his job because of the poor state of the lawns in the college! Both the present job holder and recording crew were skating on whatever the horticultural equivalent is of thin ice. He took pity on us. On our set up day in March, he arrived at half past eight in the morning to help us arrange the planks in such a way as to protect the grass more efficiently than our last effort.

Our acoustic challenges were as nothing compared to this agronomic aggravation. In the past, we had only to cope with the Gas and Electricity Boards' malevolent excavations outside King's whenever recordings took place! And local airfields were kind enough to advise the Civil Aviation Authority of our session times. The CAA then warn aircraft to avoid flying over the centre of Cambridge. It wasn't until a recording session for Britain's 'Ceremony of Carols' had to be completely abandoned, that we realised this was possible!

The soloists, choir and orchestra arrived back in Cambridge on the afternoon of our set-up day. They had just made an HDTV recording for Dutch television of the Messiah for a Good Friday broadcast. Arriving in one of King's laundry baskets with the choir's cassocks, was a vital lead which had been mistakenly sent out with another set of recording equipment to sessions at the Concertgebouw in Amsterdam. Fortunately, a colleague was able to meet up with the choir at Schipol airport and hand them the lead to bring back. With four sets of recording equipment in use at any one time around the world, it is not surprising that the odd item of equipment goes astray. Once, when we requested an ancillary piece of equipment to be sent out, whilst recording in Bayreuth, our shipping agents managed to send it to Beirut instead!

Happily, an extremely well-rehearsed set of musicians brought our recording of "Messiah" to a triumphant conclusion. Three days were set aside for the digital, time-aligned remix. Some record companies are creating a lot of publicity out of this "new" digital mixing technique, but it's been in common practice at Decca for many years now!

Just another 'Messiah'? No, definitely not! With a young chorister and a proud father on opposite sides of the microphone, this was a personal as well as a professional first!