Pulling the stops out

Two of Britain's newest organs are the work of a German builder, Philipp Klais. He impresses Adrian Jack with his ardent passion for pipes

On Monday evening, a completely new organ will be unveiled in a recital at the church of St Lawrence Jewry, next to Guildhall in the heart of the City of London. It was a Wren church until gutted by firebombing in 1940, but rebuilt much in its former style after the War. (The richly carved vestry, one of the most beautiful 17th-century rooms in London, was never replicated.) By a nice coincidence, the builders of the new organ are German – the Rhineland firm of Klais, based in Bonn.

Almost three weeks later, from October 19 to 21, a series of events at Symphony Hall, Birmingham, introduces a much bigger organ – also built by Klais. The man who won both contracts is Philipp Klais, the great-grandson of the founder of the Klais workshop. The firm has built organs all over the world, from the United States to Japan, from Greece to Iceland. But their presence in this country goes back less than 20 years. Philipp's father designed the new organs at St John's Smith Square and Gonville and Caius College, Cambridge. Philipp was responsible for the rebuilding of Bath Abbey's organ four years ago, as well as the completely new instrument in Haileybury College Chapel the year after. At 34 he is, in effect, head of the firm, though his father has not completely retired.

Philipp is as persuasive as he is personable. "Ardent" is not too strong a word for the way he talks about his projects. On average, a workshop of 60 people takes on four jobs a year. Generally, a full year is devoted to each instrument they build, but the number of workers varies according to its size. The team for St Lawrence's has eigh, plus specialist metal pipe workers. Philipp's tonal director, Heinz-Günther Habbig, is responsible for the voicing – the "personality" – of the instrument, and Philipp trusts him completely. I am to make sure I mention him. Although Philipp admits he himself has trouble co-ordinating hands and feet, so that he would never make an organist, Heinz-Günther plays like a dream.

St Lawrence's church is "a very delicate room", says Philipp. The church's organist Catherine Ennis explains that it easily distorts upper partials, so they have to go easy on the mixture stops, which add brilliant harmonics. Klais's basic eight-foot stops, the "foundation" stops, are warm. Philipp thinks they are the most important stops on any organ and that you should be able to listen to them without tiring of their sound. But every stop should be able to be played alone, and also be capable of blending, so that when you play two or more stops together the listener thinks it's a new sound, not a combination.

St Lawrence's is the church where the Lord Mayor and the City Corporation worship, so it holds services that are more pompous than the average, and Heinz-Günther gives me a blast of "God Save the Queen" as if to the manner born. It's so solid and loud I can hardly breathe, let alone join in. St Lawrence is also noted for its recitals, organised and many given by Ennis herself, so the organ must be versatile. It may look Baroque because of its case, but it is not neo-Baroque in a musical sense. For one thing, it has a swell box with shutters to vary volume – historically an English invention, though Klais has always used them. One peculiarity is that there is a side chapel which has an organ extension in it. This is virtually a separate chamber instrument which has its own keyboard, but can also be played from the main console in the west gallery. For that purpose, the action is electric, though all the rest is mechanical – now considered desirable by most players because it allows a more sensitive correspondence between fingers, and feet, and sound.

Because the old St Lawrence organ was cobbled together from existing instruments rather than built especially for the site, nothing of it has been kept except the Baroque-style case, to which has been added a "chair organ" behind the player, matching what was there before the War.

Symphony Hall's organ in Birmingham has no case, because the hall was designed with integral spaces for an instrument, as well as empty chambers for reverberation. Philipp Klais got members of the orchestra to play in these chambers to see if they would be acoustically suitable for some of the organ pipes, and he decided to install mainly "reeds" (stops whose pipes have a vibrating tongue) as well as an "unda maris", a very quiet stop with a beat, usually flute-like but, in this instance, closer to a string sound. The concrete doors of the chambers can be opened to adjust the reverberation time. There is no other European organ with this feature.

The Birmingham project is much bigger than the London one, and budgeted at £1.3 million (£15,000 still has to be raised) against St Lawrence's contract price of £420,000. There are 18 workers in the team. And it is a very different instrument apart from its size, because the model is the British town-hall organ of the 19th century – like the one close by in Birmingham itself, though that is not in good enough condition for public concerts at present. Essentially, this type of organ is a symphonic instrument, an imitation orchestra, and the City's Organist, Thomas Trotter, has brilliantly resurrected the old tradition of playing arrangements of orchestral and operatic favourites like "Ride of the Valkyries", which used to pack in huge crowds who would rarely hear a professional orchestra, let alone see inside an opera house.

With its colourful array of 82 stops distributed over four manuals, including two trumpets laid horizontally so that the sound shoots straight out at the audience, and three deep, 32-foot stops (most organs have none), Symphony Hall's organ is designed to be spectacular – "fabulous", Philipp calls it. But when I ask him who he builds an organ for, he becomes pensive. "Anywhere I work, I listen to the way people speak," because, he explains, that is a guide to their aural imagination – their musical taste, if you like. "The most important thing is to reach people's hearts." And if he seems improbably Anglophile, he did serve time on a school exchange in Cambridge, and if he has a particular affection for Birmingham, it may have something to do with the fact that, a few years ago, his young daughter successfully underwent a major heart operation at the city's Priory Hospital.

Catherine Ennis's inaugural recital at St Lawrence Jewry is on 1 Oct at 6.30pm; admission by invitation only. John Scott gives a recital at St Lawrence on 2 Oct at 1pm; retiring collection. Organ Inaugural Weekend, Symphony Hall, Birmingham, 19-21 Oct. Box office 0121-789 3333