flat sign over a trill

[pianonut]

this is probably a basic question, but i have it anyway.  if you have a flat sign over a trill, what does that mean.  for instance, in the barber nocturne there is a flat sign over a trill over an E-flatted note.  does it mean keep the E-flat and trill to the next whole note or trill to a half note.  in other words, does it mean to START on the flatted note.  or does it mean to trill a half-step from the flatted note - from E-flat to E-natural?

[Torp]

I believe you play the E-natural, but technically it's an F-flat.  Since an unmarked trill from an Eb would be between Eb and F, by putting the flat sign, it indicates to flat the trill note, i.e. the F, giving you Fb.

I think I'm right, but perhaps someone can give a better explanation.

Jef

[pianonut]

thank you.  i've been practicing it wrong for weeks.  just saw it today.  shows how much i know.  oh, well.  it sounded better to me at first the other way.  now, i see it's sort of minor sounding and needs the F-flat note to make it sound correct.  interesting!

[quantum]

An accidential over a trill sign is applied to the auxilliary note of the trill (the note above the main note written).  The auxillary note is usually one LETTER above the main.  Eg: If you have a written C, aux is D.  The auxillary, usually follows the key signature, or the immediate harmony of which it is in context.  If there is to be any deviation from this it is usually written as an accidental above or beside the trill sign. 

In your case: Written Eb trills with some sort of F.  Because there is a flat over the trill you trill Eb to Fb. 

[pianonut]

thank you both.  what i hate is practicing something wrong for weeks, and then saying 'oh, what is that?  a flat sign over the trill.' 

[Torp]

An accidential over a trill sign is applied to the auxilliary note of the trill (the note above the main note written).  The auxillary note is usually one LETTER above the main.  Eg: If you have a written C, aux is D.  The auxillary, usually follows the key signature, or the immediate harmony of which it is in context.  If there is to be any deviation from this it is usually written as an accidental above or beside the trill sign. 

In your case: Written Eb trills with some sort of F.  Because there is a flat over the trill you trill Eb to Fb.

See...I knew someone would provide a more accurate explanation.

[Bob]

Yes, what they said.  (the intelligent answer by Bob )

I think it's also used in situation where the amount of notation can clutter things, just as an extra reminder.  Or if that upper aux note was alter earlier in the measure, it's how the composer can control the aux note on the trill.

[pianonut]

what if...what if it is the auxillary notes alter ego?