There are some basics in conducting concertos or solo pieces that are necessary to adhere to. First of all, the soloist has a lot to think about, and the last of these should be the conductor. The soloist should have no thoughts that the conductor is going to give an inaccurate tempo, miss an important cue, or be insensitive to when the soloist might want to push or hold back the tempo. A rapport between the soloist and the conductor needs to be developed before the first orchestra rehearsal, so that the rehearsal time isn’t spent dealing with issues that could have been decided upon beforehand.
Meeting with the soloist before the first rehearsal, preferably with the soloist’s accompanist, will, of course, help establish tempo and various other nuances. The conductor may make some observations, but the kind of comments may depend upon whether the soloist is an experienced performer or a student. Recording both the session with the soloist and piano accompaniment and, if permitted, any orchestra rehearsals, is extremely helpful.
Once the rehearsal has begun, balances need to be dealt with so that the soloist never has to be concerned with pushing his or her sound to get over the orchestra. Issues that cannot be predicted will come up during rehearsals but making sure that the soloist is always heard is the most important. Having an assistant or, if in a school situation, the soloist’s teacher in the concert hall listening for balance can be very helpful, as the conductor’s podium isn’t always the best place to make the necessary adjustments. As with rehearsing orchestral works, it’s generally helpful to rehearse larger sections of the piece before dealing with details. Especially in student situations, young soloists usually find it helpful to play through larger sections, and then go back to work on various details, rather than stopping too often.
Clearly certain instruments require more care in balancing than others. I’ve had the pleasure on several occasions to conduct for the wonderful guitarist Jason Vieaux. When performing with orchestra, Jason always plays amplification, which he monitors very judiciously. A piece such as the Ginastera Harp Concerto necessitates in certain passages extreme adjusting of dynamics to enable the harp to be heard. A recent performance of a different harp concerto which I conducted used subtle amplification.
Extra care often must be taken when the soloist plays in the lower register. Viola and cello concertos are often written in the same register as the orchestra, which can cause balance issues. Flute concertos can be difficult to balance. Thankfully piano and brass instruments have far fewer balance problems.
Young musicians need to be taught to play very softly at times. String players who have worked their whole lives to make a beautiful sound are suddenly often asked to play with no vibrato, slow bow speed, at the upper half of the bow, and with one hair of their bow. It’s absolutely vital that the musicians play the dynamic that enables the soloist to be heard, which often seems to contradict the indications in their music. A marking of mezzo forte or forte may often need to be played much softer than that indication might imply, and overdone crescendos must be avoided if they cover the soloist.
My particular style of conducting concertos encourages the orchestra members to listen closely to the soloist. The information which the soloist is giving is heard by the entire orchestra, not just the conductor. The more that the orchestra can feel that they are a part of the process of putting together the ensemble, the more they will respond to the nuances of the music. For me, smaller beats work better, as this tendency gives confidence to the players to react to the soloist along with me. Conducting with large gestures can also encourage the orchestra to play too loudly. When tutti sections do come along, larger gestures will highlight the contrasts even more.
Often the concertos or solo pieces are quite substantial, and care must be taken not to shortchange rehearsing them. Pieces like the Copland Clarinet Concerto or any of the Bartok Concertos, for example, are very difficult, and ample rehearsal time must be set aside for them. If a program has one of these pieces, it would probably be necessary to balance the rest of the program with music which is surely significant, but somewhat less challenging. My colleague recently did a program with the fiendishly tough Bartok Violin Concerto #2; having done this piece several times, I’m very aware of its difficulty. He balanced it well with the Dvorak Symphony #8, a wonderful piece, but definitely doable alongside the Bartok Concerto.
Certain matters of protocol exist when soloists are part of the equation. The conductor must introduce the soloist to the orchestra enthusiastically. If time permits, and if it’s determined to be advantageous, the orchestra can do a rehearsal without the soloist. If not practical, working out certain sections of the piece before the soloist plays, or pointing out various potential issues before starting can save time and energy.
If the soloist begins a movement or a section of the piece after stopping during rehearsal, or when starting a movement or new section during the concert, the conductor should look at the soloist, and then begin. The soloist must not give a physical indication for the conductor to start, but take the cue from the conductor, along with the rest of the orchestra.
If the soloist perceives a problem during a rehearsal, the soloist must speak with the conductor, never to the orchestra. On occasion, the soloist might ask the conductor if he or she can address the orchestra directly, but this situation must be handled carefully. The conductor can never be made to lose face in front of the orchestra.
I always have a copy of the cadenza, no matter how obvious the subsequent entrance of the orchestra is. On one occasion, the soloist decided to omit a section of the cadenza, and I was able to recognize what he was doing and bring the orchestra in correctly. Often it is helpful to predetermine the number of beats at the end of the cadenza, usually during a trill, that the soloist uses to lead to the orchestra’s entrance.
During the performance itself, the conductor must be aware that the soloist may play a bit differently from the rehearsal. Small nuances of tempo and color may vary from rehearsal. Seasoned soloists may hold back slightly during rehearsal and play with more verve and passion than in rehearsal. Young soloists may get excited and inadvertently rush. The conductor should be aware of this phenomenon and be ready to adjust as needed. I had the occasion to conduct the Grieg Piano Concerto with a soloist who had played the piece many times. Rehearsals went smoothly, and I felt comfortable and at ease. However, when the performance started, several small variations of what we had rehearsed became evident, and I needed to stay on my toes throughout. It was an exciting and riveting performance, and I greatly admired our pianist for his ability to take a piece that he had played so many times and making it unique and special for us.
There’s a joke that reads something like this – “If there’s a disagreement between the soloist and the conductor, who prevails? Whoever is getting paid more.” In realty, if what the soloist requires is reasonable, the conductor needs to go along with the desired interpretation. The conductor might make a few suggestions or requests, i.e., can you watch me for this downbeat, can you be careful to hold the tempo for a particular passage, but for the most part, adherence to the soloist’s interpretation should be the norm.