Are instructions on organ stop settings included in the notation of Baroque organ music?

Question

I am currently listening to a collection of Bach's complete organ works for the organ. I love Baroque music and Bach in particular, but I am not very familiar with the organ from the performer's perspective (I play the piano). I know that the organ console has sets of "stops" which are used to activate sections of pipes which may have the same pitch, but different sound characteristics, but that's about it.

Anyway, while listening to the music, I noticed some of the works sounding radically different from that dictinct, powerful organ sound. Some of them sound kind of squeaky, the bass and lower treble just a distant, nasal hum. I was wondering if it could be recorded on a different instrument, or were just different stops activated? If so, is the usage of those regulated in the notation, or is the performer supposed to excercise their own discretion? I suppose that since the organ doesn't have a dynamic keyboard, the performer has to use some other means of obtaining different sound dynamics, are these the employment of stops?

Answer 1

Yes, dynamic changes are predominantly achieved by choosing different stops. No, baroque music virtually never specifies which precise stops to pull. The most you can expect is something general such as "Sur les flûtes", or "organo pleno" - and even this doesn't mean what you might think (almost never "all existing stops", usually something more like "stops from all available octaves"). This is just part of a general trend towards more explicit notation as time progressed; a baroque performer was supposed to understand which phrasing, dynamics, tempo and ornaments to use from the structure of a piece without being told. (It's the modern emphasis on originality and an individual artistic expression which requires the over-detailed instructions in modern scores.)

So how do you know which stops to pull? There are very general guidelines how to construct a useful sound ("select a base octave and build a 'pyramid' on it"), genre- and form-specific traditions ("a 2 claviers" goes well with a characteristic solo stop and subdued accompaniment), pointed opinions by prominent authorities ("never use 16' for Bach's sonatas")... and all too often inverse opinions by other respected authorities. To top it all off, every decision must be revisable depending on the room and the instrument you are performing on (which is often completely different from what the composer ever played).

Knowing these different principles is part of learning to play the organ, and every teacher must be able to convey this knowledge.