Incidentally, if it's inbetween the D's, Pogo had a good suggestion also. If it is between the D's, you may be able to do a 34 trill, but I still don't like it with the hand spread out. I would probably still release at least one of the notes myself.
How could you hold a D with your fifth finger(Not even worrying about holding the other D) and trill on the E and F below it with 34?
I had a feeling that wouldn't be as clear as I hoped. Hold an octave D-D, and trill 34 on the EF between the D's. (I don't think that's what's going on in this piece, but if it was, it would be an option.)
I dont think that's possible... who can reach f to d with 4-5?
If you're playing a Bdim chord, 1st inversion, you'd play 5421. (DFBD)
I'm so confused.
My impression was that you were ultimately suggesting a reach of F-D with 4-5.
Once I read your reply, I had a feeling that was the case. I'm not sure whose hands would be large enough to reach that, but mine most definitely are not!
OP- Okay, so the EF trill is in-between the D-octave. Great. You have quite a few options:
1. Hold the 15 octave (but release the tension in your hand, as Pogo suggested), and play the trill with 34.
2. Release your thumb, as pianoloverus suggested, but continue to hold the bottom D. Play the trill with whichever available fingers feels most comfortable. (You may have to switch fingers on the bottom D to make this more comfortable. IE, replace the 5 with a 4 or even a 3, depending on which fingers you trill with.)
3. Release your pinky, but continue to hold the top D. Play the trill with whichever available fingers feels most comfortable (probably 35 or 45).
4. Release the octave entirely, and play the trill with whichever fingers feel most comfortable (probably 23, 12 or 13).
I would not take my original suggestion that you might play the trill all with the thumb. That was under the impression the stretch was a minor tenth, which is no longer the case. That suggestion is definitely no longer valid.
Hope this was more helpful.