THE 2013 Edinburgh International Festival (EIF) had a theme: Technology.

This year's programme included three Requiem settings: by Brahms, Fauré, and Verdi; and yet Sir Jonathan Mills does not end his term as director until 2014.

It would seem that these were, quite simply, works that the various performers wished to perform. They were also vehicles for the two choruses who regularly perform at the EIF to show what they can do.

Fauré's Requiem was performedby the Scottish Chamber Orchestra and the National Youth Choir of Scotland, conducted byRobin Ticciati. The soloists were Daniel Doolan, treble, and Sir Thomas Allen, baritone.

The programming was strange, to say the least. In the first half we heard Debussy's (arranged by Sachs) Prélude à l'après-midi d'un faune, followed by Schoenberg's Verklärte Nacht. After the interval, we were offered Webern's Five Pieces for Orchestra, Op. 10, and then the Fauré Requiem.

The music in the first half was well played and enjoyable to listen to. Ticciati drew impressive atmospheric and colourful playing from his orchestra. The two pieces, however, might more usefully have been the first half of a completely different concert.

The two pieces in the second half could logically have constituted a programme by themselves. I imagined Webern's five pieces as tiny "lives" in Petri dishes, viewed through the lens of a microscope, each "life" being colourful and very short-lived.

Perhaps the Fauré Requiem celebrated these five short lives. This was an even and well-balanced performance. The National Youth Choir of Scotland sang with great assurance and a warm tone. The different sections blended well and and executed seamless entries.

For a youth choir, they were very impressive. The two soloists gave very personal performances. Doolan, treble, was a replacement in the role. His opening phrase in the Pie Jesu was nicely coloured, clear, and firm. Sir Thomas seemed, in contrast, to be ill at ease and tentative, especially in "Hostias et preces tibi". It was as if he had rehearsed to perform in a modest village church, but seemed slightly pushed to project to the rafters of the Usher Hall. The thoughtfulness of his phrasing of the text and colouring of the music could not disguise his apparent vulnerability. Ticciati conducted his forces warmly and with great feeling.

MAHLER's "Resurrection" Second Symphony, was given a splendid performance by the Bavarian Radio Symphony Orchestra, which sprang from the innermost thoughts and sensibilities of the conductor, Mariss Jansons. His knowledge and obvious respect for Mahler's symphonies offer listeners uncluttered performances devoid of excessive emotional glare or "boy-racer" fluctuations in tempo.

The opening and closing moments of the first movement were great examples of the above qualities, especially the point at the end where there is a descending flurry down through the string sections of the orchestra to arresting pizzicato notes. The decent was even and the pizzicato notes were pianissimo, but I guarantee that they would have been clearly audible at the back of the hall.

Having travelled Mahler's journey to the point where the distant "resurrection brass" play, Jansons showed, again, how well he understood the acoustic capabilities of the Usher Hall. The brass sounded in turn from the lobby of the upper circle, and then from off-stage right, and then left. At upper-circle level, no doors were open to the auditorium, and the sound was ethereal and arresting.

There followed more brighter brass from the off-stage bands. An atmosphere had been created, where all too often the effect is of a vulgar fanfare announcing the "The big song is next." The singing of soloists Genia Kühmeier and Anna Larsson came from near the back and to the left-hand side of the orchestra. This allowed their sound to come as if from within the chorus, as Mahler intended.

The Edinburgh Festival Chorus were seated, and sang their opening entries from that position. When they stood, the obvious increase in volume was sensational. Their diction was clear and nicely rounded. The closing pages of the last movement were created by Jansons as carefully as he had the closing pages of the first movement. The full orchestra drew the performance to a fitting close with the strength and power of its playing: not just the volume.

DR JOHN KITCHEN is a Senior Lecturer in Music at the University of Edinburgh. He also holds the post of University Organist. It was in his capacity as Edinburgh's City Organist that he gave an illustrated introduction to "How a Pipe Organ Works".

He began by playing an arrangement of a piece by Handel. He described it as sounding as Handel would never have heard it. Having let the organ speak for itself, he then introduced us to it.

The Usher Hall organ was built in 1913 by Norman Beard of London. It is a romantic concert organ, and was played by Widor in 1914. It has 63 stops, and in excess of 4000 pipes. It is a special organ, because it retains the original specification: no alterations have been made. By the 1970s, it had fallen into an unplayable condition. It was restored and re-installed in 2002 by Harrison & Harrison of Durham, who are involved in the final stages of a similar project for the Royal Festival Hall organ in London.

Kitchen explained that this organ was built at a time when tracker action (where the link from playing a key to the sound coming out of a pipe was achieved by a system of rods)had been abandoned by all but the purists. This organ has electro-pneumatic action, where the opening of the valve allowing air into an organ pipe is assisted by the electric control of a sequence of valves pushing air to the valve of individual pipes. One of the main benefits of this system is that it allows the console (containing the keyboards/manuals, pedal board, and stops) to be at a remote location from the pipes themselves.

He explained that a stop is a row of pipes that produces a specific sound, and that there are two types of pipes: flues and reeds. Sound is achieved by passing "air under pressure" to the pipes. Flues are pipes where air is forced across the rectangular opening (mouth) found on the front and on the bottom half of the pipe. This causes vibration to travel through the pipe to create sound. (Think of a flute). The other type have a vibrating tongue within the pipe that creates the sound.

The wind is at a constant pressure. The pipes sound at a fixed volume: it cannot be increased. "That's strange," I hear you all think. There are changes in volume. They are achieved by having some stops/pipes in an enclosed box. This box has louvred openings. When they are shut the pipes sounds are muffled/muted. As the louvres are opened the enclosed pipes can speak more freely out into the auditorium: thus achieving a crescendo. The other way of affecting the volume is the choice of stops. Bigger pipes tend to make a bigger sound and smaller pipes a smaller or more shrill sound.

Now we come to the tricky subject of registration. This is the choice of which stops to use: which to use when and which to use together. Different organists can play the same piece of music on the same organ and yet all can sound different. The choice of stops changes the colour and feel of a piece of music.

The last big mystery that was explained was how an organist (a single person) can change so many stops while playing four manuals and a pedalboard. "Pistons" is the answer. These are buttons situated under the keys on the manuals and above the pedals. Before performing, the organist can preset combinations of stops and assign them to a specific button: hence two or more stops can be engaged by pressing only one button. And just to make things easy for the organist at the end of a performance, they do not have to all the individual stops back in individually. There is a piston called General Cancel. If you press that, all the engaged stops jump back to the disengaged position in one single action.

Thank you, Dr Kitchen, for helping make all that technology clear to us.

The other two Requiem performances will be included in next week's review.