Trills relating to Bach

[i_am_joey_jo]

Are there rules regarding trills in Bach or Baroque music in general?  I have seen the wiki on trills and yet sometimes my teacher tells me to go with "what sounds right to me."

For example let's just use the basic trill or the mordent trill: Sometime a normal trill will start a semitone or a full tone above the note, sometimes it will start on the trilled note even though the trill signature is the same.  Often it seems improvisation is the best.

Please tell me if there is a set law on trills or if the principles my teacher is talking about are best.  Is this one of the ways we can make a baroque-period piece our own, by giving the trills the form we choose?

[quantum]

These may get you started:
https://www.amazon.com/Ornamentation-According-C-P-E-Bach-Quantz/dp/0759609357

https://www.amazon.com/Ornamentation-Baroque-Post-Baroque-Special-Emphasis/dp/0691027072/ref=pd_cp_b_2

This is a good concise book:
https://www.amazon.com/Ornamentation-Question-Answer-Valery-Lloyd-Watts/dp/0882845497

https://books.google.ca/books?id=YXHIJIma0FsC&lpg=PA27&ots=3t4exZzCZu&dq=Ornamentation%3A%20A%20Question%20%26%20Answer%20Manual&pg=PP1#v=onepage&q&f=false

[stevebob]

You might find this useful:

Bach Notation

Doing "what sounds right" sounds evasive, and I don't think it's very sound advice.  I would expect a more informed response from a teacher.

[lienetje]

Hi,

Bachs music is written for harpsichort, from there the very long trills.....
I Play the trills very short for example only do, re, do, or; do, si, do, otherwise it sounds hard.
It's always very difficult to play them alike.....

( Do not look to my english )

liene

[dorfmouse]

The Dolmetsch Online site will give you many possible answers to your question. You might wish you never asked; the question of baroque ornamentation is the stuff PhDs are made of.
 
The ornament table that JS Bach produced is in there somewhere and is probably most relevant to your question. Seems like your teacher is somewhat clueless in this field - doing what sounds right may be an option, but it should surely be an informed option from a professional.

https://www.dolmetsch.com/musictheory23.htm

The site is fantastic for music and theory questions