Tetrahedral Recording Session Images
Date: 8th May 1971
Venue: Merton Chapel, Oxford
Preparing for the session
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Michael setting up the tetrahedral Calrec arrangement. (April 1971)
![2 calrec 4 web 2 calrec 4 web](https://intothesoundfield.music.ox.ac.uk/sites/default/files/intothesoundfield/images/media/2_calrec-4-web.jpg)
Close up of Calrecs in the tetrahedral arrangement.
![3 calrec 4 plus ric good gray web 3 calrec 4 plus ric good gray web](https://intothesoundfield.music.ox.ac.uk/sites/default/files/intothesoundfield/images/page/3_calrec-4-plus-ric-good-gray_web.jpg)
Richard Cowderoy was one of the most committed, enthusiastic and technically capable members of OUTRS, and without his input it is hard to see how the increasingly ambitious projects could have been completed to such tight deadlines. He had a good grasp of the technical issues and so was able to hold his own in discussions with Michael and Peter. Crucially, he also had the skills and experience needed to build the complex circuits designed by Peter, including a 30W Class A power amplifier (see Electronic Music Concert). Richard was extremely helpful and easy-going with a good sense of humour, and was a great asset to the team. After completing his degree he stayed on to do postgraduate work in computing, and continued to take a leading role in audio projects. His other great enthusiasm was gliding, the attractions of which remained rather a mystery to the rest of us. Years later, this all-consuming interest led to tragedy when he was killed while flying in the French Alps, leaving his wife and two young children.
![4 1 pgc ric 1 g web 4 1 pgc ric 1 g web](https://intothesoundfield.music.ox.ac.uk/sites/default/files/intothesoundfield/images/media/4_1-pgc-ric-1-g-web.jpg)
Peter and Richard working under pressure on the Quadracronic and differential amplifier in Richard’s room in Lincoln College, just before the tetrahedral recording experiment. A partly-completed 30 W class A amplifier (see Electronic Music Concert) can be seen in the background at the far right.
![5 2 pgc ric 2 g web cr 5 2 pgc ric 2 g web cr](https://intothesoundfield.music.ox.ac.uk/sites/default/files/intothesoundfield/images/media/5_2-pgc-ric-2-g-web_cr.jpg)
A steady hand: Peter soldering the differential amplifier. It was not working properly until a few minutes before the concert!
![6 4 pgc ric 4g web 6 4 pgc ric 4g web](https://intothesoundfield.music.ox.ac.uk/sites/default/files/intothesoundfield/images/media/6_4-pgc-ric-4g-web.jpg)
Richard checking the performance of the Quadracronic on an oscilloscope. On the table (far left) is Richard’s digital computer under construction.
Recording Session
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The Sacristy, Merton College Chapel, on the evening before the concert: setting up the Crown 6.25 mm four channel tape recorder
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The Crown in close-up
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On the day of the performance, we started by using a rope to measure the tetrahedron.
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Measuring continued...
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Relaxed…Peter’s calm manner was helpful in dealing with Michael, who could become over-excited under stress.
![12 12 mag and quads 2 g web 12 12 mag and quads 2 g web](https://intothesoundfield.music.ox.ac.uk/sites/default/files/intothesoundfield/images/media/12_12-mag-and-quads-2-g-web.jpg)
Michael with some of the eight Quad valve amplifiers that were used in the experiment.
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Despite his poor health, Michael was capable of considerable physical effort when the occasion demanded.
![14 37 nulling calrecs g web 14 37 nulling calrecs g web](https://intothesoundfield.music.ox.ac.uk/sites/default/files/intothesoundfield/images/media/14_37-nulling-calrecs-g-web.jpg)
Nulling the Calrecs: the differential amplifier is used to match the sensitivities of the Calrecs by a nulling method. Details are given in Michael’s article in the September 1971 issue of Studio Sound. [Tetrahedral 2]
![15 19 mag testing in chapel g 15 19 mag testing in chapel g](https://intothesoundfield.music.ox.ac.uk/sites/default/files/intothesoundfield/images/media/15_19-mag-testing-in-chapel-g-.jpg)
In the Chapel, Michael (standing, rear left) tests the set-up by clicking his fingers at each microphone in turn.
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![17 30 guests 1 g web 17 30 guests 1 g web](https://intothesoundfield.music.ox.ac.uk/sites/default/files/intothesoundfield/images/media/17_30_guests_1_g_web.jpg)
Guests in the Sacristy.
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Stepladders precariously support the front left and rear right Spendor BC1s as guests listen to the relay.
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Michael and guests.
![20 33 guests 4 g web 20 33 guests 4 g web](https://intothesoundfield.music.ox.ac.uk/sites/default/files/intothesoundfield/images/media/20_33-guests_4-g-web.jpg)
Listening attentively.
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General view including the Scully tape recorder.
![22 35 scully 2 g web 22 35 scully 2 g web](https://intothesoundfield.music.ox.ac.uk/sites/default/files/intothesoundfield/images/media/22_35-scully-2_g-web.jpg)
Close up of 12.5 mm Scully
![23 36 scully 3 g web 23 36 scully 3 g web](https://intothesoundfield.music.ox.ac.uk/sites/default/files/intothesoundfield/images/media/23_36-scully-3_g-web.jpg)
At the controls
Playback
![24 40 pb pja at pno g web 24 40 pb pja at pno g web](https://intothesoundfield.music.ox.ac.uk/sites/default/files/intothesoundfield/images/media/24_40-pb-pja-at-pno-g-web.jpg)
Relaxing at the piano....Philip
![25 42 pb mag at pno g web 25 42 pb mag at pno g web](https://intothesoundfield.music.ox.ac.uk/sites/default/files/intothesoundfield/images/media/25_42-pb-mag-at-pno-g-web.jpg)
…and Michael (he would have been pleased to see the score of a piece by Alban Berg, one of his favourite composers)…
![26 41 working g web 26 41 working g web](https://intothesoundfield.music.ox.ac.uk/sites/default/files/intothesoundfield/images/media/26_41-working-g-web.jpg)
…while others do the work!
![27 43 pb crown g web cr 27 43 pb crown g web cr](https://intothesoundfield.music.ox.ac.uk/sites/default/files/intothesoundfield/images/media/27_43-pb_crown_g-web_cr.jpg)
Setting up the Crown