I learned something today: I don't really like the sound of the large organs in concert halls.
The ConcertGebouw is one of the grand dames of concerts halls, built 1888. They have hundreds of performances a year! On many Wednesday's they have a free concert. Today was a 30 minute organ concert. It's one of the those massive organs with many many large pipes. The sound is massive too, and the bass notes practically shake the building. But it's all a mush to me with no vibrato and all of equal volume. It is hard for me to hear the start and stop of notes.
The main floor of the grote haal was packed, so I guess there is a lot of interest in the classics in Amsterdam.