As an organist I'm not content with the 'most used registrations' that you normally get with a virtual pipe organ. After all, Bach got in trouble with his employers for using 'strange registrations', and the student (me) is not above the master (Bach)!

There are other organ libraries, but they have their problems: notably the PMI is a lovely but small baroque instrument (but you do get to control individual stops if you want), and the NDB (Notre Dame de Budapest) is a lovely large romantic instrument for which you get nice combinations, but very few individual stops.

The Konzerthaus organ gives you the best of both worlds--combinations (which reduce polyphony) and individual stops when you want them. It is definitely my 'go to' virtual organ library.

There are a couple observations, however. For one, there is no tremulant. (There are a couple 'celeste' stops, but that is not the same.) I haven't yet tackled simulating tremulant with LFO (low frequency oscilators) in Cubase, but I expect that a passable one is possible.

Also, there are curious discrepancies between the actual software product and its documentation. From the introduction in the Konzerthaus manual we have:

Welcome to the Vienna Symphonic Library’s Konzerthaus Organ. This Collection contains an ample selection (so this is not the complete Konzerthaus organ?) of stops from the organ in the large hall of the Konzerthaus in Vienna, resulting in a virtual instrument featuring three manuals and a pedal (but the software has FOUR manuals and pedal). The Konzerthaus Organ was built in 1913, during the decline of Romanticism and the rise of Historicism, by the renowned brothers Rieger in Silesia. They tried not only to integrate Baroque elements according to Bach and Silbermann, but also to make the instrument as versatile as possible by implementing modern achievements of disposition and intonation. It was the first organ with 5 manuals in the Austrian Empire (does it still have five? Did Vienna sample 4 out of 5 manuals?) and still is the largest one in Austria, comprising 116 voices in five manuals and one pedal.

Aside from minor questions from reading the manual (who reads manuals anyway?), I am really happy with this product. VSL has done it again!

No tremulant, eh? In my career I've played on hundreds of different organs, and except for very small 2-3 rank positif type instruments I have yet to encounter an instrument with no tremulant at all. I find it hard to believe that the 'pride of Austria' is lacking such a basic effect (dating back to the 16th century).

From a technical point of view, I can appreciate how it may be a nasty a problem to synchronize tremulant samples, not to mention that including them would considerably increase the sample set size.

Nevertheless, it is still a lack in the Konzerthaus Organ sample set, and is missed.