Every rehearsal is different. I’ve been thinking about what rehearsal playing requires and how the requirements change every few seconds.
If you are a soloist, you will find yourself thinking about everyone else during rehearsals for the first time. The way rehearsals proceed may be new to you. It’s a completely different ball game.
Playing for singers one-on-one is also very different. The amount of space between sounds in a larger rehearsal has just increased enormously. In addition, there are many more voices and vocal lines, plus a conductor. You may be required to rehearse in a space with bad acoustics. The way you play (shorter or longer notes, more accents, less pedal) will be a great help.
Most important ~ keep the rehearsal moving. Watch the conductor, listen to the singers, anticipate what is needed. The pianist should know intuitively where the conductor will start after a break to discuss a passage. (How? Listen to the discussion! And remember what happened just before the conductor stopped. Chances are, that’s the spot.) Give pitches near the end of the discussion, before the downbeat. If more time elapses than you had anticipated, give them again.
If your hands remain on the keyboard, chances are much greater that you will be there when needed. Early.
Listen to what is happening in the room. The singers need to hear you play what they are having trouble with. You will be playing whatever you don’t hear them singing. If the music is moving through potentially confusing harmonies, try adding chords at the harmonic changes, or play the bass line. (Both choices should be in a different range from the vocal part being rehearsed for reasons of clarity.)
When the conductor needs your help
From time to time, I have encountered a conductor who doesn’t know the music. Maybe the composer is new to him/her. What is appropriate here? Must you always “follow” the conductor?
I tried playing the parts unobtrusively, so as to help the rehearsal progress but not to call attention to the situation. It worked.
Sound as much like the orchestra as possible. Listen to recordings so you know the orchestration and can reproduce the sound. A solo flute sounds completely different from a solo trumpet, for example. And those arpeggiated chords in piano reductions are often added when the stretch is too wide for the hand to reach. They do not often indicate a harp part. So why would you arpeggiate them? Find another solution.
After piano rehearsals are over, the singers will have to adjust to the sound of the orchestra from the distance of the stage to the pit. Often from the back of the stage to the pit. It is your job to help them make that transition.
The singers have much more to think about here. Your job is to play the orchestra part prominently and very clearly. Follow the conductor, not the singers. You should be overplaying. An exagerrated crescendo (when marked in the score) before a singer’s entrance, for example, would be welcomed. Any musical cues must be prominent as well.
Rhythms need to be emphasized, as the singers are most likely not looking at the score. (Is it a triplet or a dotted rhythm? Make it clear.) Also important are key changes, accidentals that could sound like mistakes, meter and tempo changes.
When the articulation changes from staccato to long legato phrases, emphasize that.
If there is a secondary part that matters, play it, even when rehearsing a single line.
When a singer is marking
This does not mean that you mark, too. Everyone needs to hear the orchestra. Balance is not the issue. You will not be able to listen for ensemble, so just play it like it goes as much as you can. Of course you will be singing the solo part so you know the time needed to prepare for and reach a high note, say, and to breathe with the music as the singer would.
A singer who is marking is feeling vulnerable. You can help her/him feel secure.
Any especially difficult page turns must be dealt with before the first rehearsal. Copy what you need to, then use tape so everything remains secure. Stopping a rehearsal so the pianist can catch up is a waste of everyone’s time, and avoidable. The goal is to be helpful, not get in the way.
Repeats and cuts ~ same solution. If they involve turning more than one page, mark them with post-its.
Please leave a comment if you have additional suggestions.