Concerto ("con-CHAIR-toe") started life meaning "concert" in Italian. In today's musical lingo, though, a concerto is a piece of music in which one player (the "soloist") sits or stands at the front of the stage playing the melody while the rest of the orchestra accompanies her. The concerto soloist is the hero or heroine, the lead of the play, the prima donna. She doesn't even have to look at the conductor — the conductor follows her.
In most great concertos (or concerti), the orchestra doesn't just accompany the soloist by playing quiet oompahs under the soloist's melody. In the greatest concertos, the orchestra has an equal part, conversing back and forth with the protagonist, "Dueling Banjos" style.
Sometimes (as in the great concertos of the Danish composer Carl Nielsen [1865-1931]), one other member of the orchestra even acts as antagonist, seemingly arguing back and forth with what the soloist has to say. (This argument is done musically, of course — although concert attendance might go up if the antagonist could really argue with the soloist. "What?!? You call that a melody? Get off the stage, you amateur!")
Concertos are a lot of fun for the audience. If you haven't heard one, you're in for a treat. Many audience members go to a concert mainly for the concerto. They come to hear a great, famous soloist; to witness her flashy pyrotechnics; to be swept away by her outpouring of musical passion; and to check out her outfit.
For this, soloists are paid dearly — sometimes $30,000 to $50,000 for one performance. Orchestras pay because they know that they're going to make the money back. Sometimes concertgoers buy a season ticket just to have the chance to hear a famous soloist.
If you're going to an orchestra concert that includes a concerto, buy a seat a little to the left of center. The soloist almost always stands or sits just to the left of the conductor. If it's a piano soloist, sit even farther to the left (the extreme left is okay as well). The piano is always situated with the keyboard on the left side, and you'll have more fun if you can see the pianist's hands. (You'll have no fun sitting front-row center, however, because the piano completely blocks your view.)
Concerto structure
The average concerto lasts about 30 minutes. Concertos almost always have three movements — that is, three contrasting sections separated by pauses. For most classical composers of old, a concerto was expected to have three movements, just as most Hollywood movies are two hours long, just as most Broadway shows have exactly two acts, just as a limerick has exactly five lines, just as most rock songs are three minutes long, just as Dennis Rodman's hair color changes every six weeks.
In most cases, the three movements of a concerto fall into this scheme: FAST-SLOW-FAST. This setup, which has been around for centuries in all kinds of music (and in movie plots, by the way), works especially well in a concerto, enabling the soloist to show off her amazing technique in the first and last movements and to bring the listener into a more intimate, soulful world in the middle.
Soloists always play from memory, unlike the musicians in the orchestra, who read from sheet music, or the conductor, who's probably using a big, bound score. This habit is a holdover from the days of the great virtuoso superstars, such as Franz Liszt (1811-1886), who were the "rock stars" of their generation. The audience expects a star, and stars don't mess with sheet music.
Meanwhile, the orchestra is chugging along like a train on its track, unable to deviate from the written music. In other words, the soloist cannot slip up. But sometimes she does — with hair-raising results. The conductor and orchestra must react with split-second timing. If the soloist skips three pages of music — which is entirely possible, because the music at the beginning of a piece often repeats at the end — the conductor must figure out where she skipped to and somehow signal to the orchestra when to come back in.
If conductor and orchestra can react quickly, the audience may never even notice the mistake. But sometimes orchestra and soloist are out of sync for a minute or more. And in some cases, the conductor must resort to desperate measures to let the orchestra know where the soloist has gone. If you're ever listening to a concerto and the conductor yells, "Skip to Letter F!," you know what happened.
The cadenza
Near the end of every movement of a concerto is usually a moment where everything seems to stop — except the soloist. The soloist takes off on a flight of fancy, all by herself, lasting anywhere from ten seconds to five minutes. This is not a mistake. It's called the cadenza: a moment devised by the composer for the soloist to show off.
Cadenza is Italian for "cadence" (not to be confused with credenza, Italian for "piece of dining room furniture"). A cadence is a simple falling progression of harmonies, one chord to another, ending with a natural resting-place chord.
But toward the end of a concerto movement, this falling progression is interrupted. Before the final chord or chords of the progression can be heard, suddenly everything stops and the soloist does her thing. If she does it well, she can actually create suspense and anticipation, just like a sneezer who goes, "Ah . . . ah . . . AH . . . " and makes you wait for the "choo!"
Then, after the soloist finishes, the orchestra comes in with the final chords. It's great.
In the old days, soloists made up their own cadenzas on the spot. The great composers, who were often wonderful soloists themselves, took special pride in doing this kind of improvisation. But other composers, including Beethoven, wrote down specific notes to be played in their cadenzas. These days, soloists usually play a cadenza that somebody else has composed. In any case, the cadenza is meant to sound improvised. If you get the impression that the soloist is playing her cadenza as if she just made it up, she's playing it well.
Just about every cadenza ends with a trill. A trill is the quick alternation of two notes that are next to each other. Try it — it's easy and fun!
1. Sing any note.
2. Now sing the note right above it.
3. Repeat steps 1 and 2, faster and faster.
This is a trill.
A trill is actually quite a bit easier to play on an instrument. In the old days, a trill was the signal from the improvising soloist that she was just about done with her cadenza. It was the sign to the orchestra and conductor to wake up, put their magazines down, and get ready to come in with that final chord. At the end of the trill, the soloist and conductor watch each other, breathe together, and play that final chord together.