For decades, Peter Planyavsky was the organist and/or music director of the Stephansdom in Vienna, one of the world's great cathedrals. The highlight of his tenure was undoubtedly the installation of the Rieger organ in 1991. It must certainly be the most heroic 56-stop tracker ever built! Playing a concert on it in 2001, on my very first European tour, was one of the great thrills of my life (especially the Liszt B-A-C-H). The 32' Principal does not purr; it roars. And I remember the Pedal reeds 16' and 8' being so large-scale that, even in big pieces, I usually used one or the other. But then there were more delicate colors on the Brustwerk and elsewhere. In fact, I had no trouble finding the right textures for the Bach Trio Sonata that I played. (I can't think of many cathedrals in which I would attempt such a work.) On the Solowerk, the big reed with the big cornet enable a melody to soar above the rest of the organ in a very Planyavskian sound.
The Pipedreams website has featured this instrument in five of its problems. Links to all can be accessed from this page:
http://pipedreams.publicradio.org/gallery/austria/vienna_stephansdom_rieger.shtml
Photo: the author at the Stephansdom organ (July, 2001).