Instrumental ensembles

Little music is written for one instrument alone. Most of the time several instruments play together, and the group they form is an ensemble. What names an ensemble is, before anything else, its size: how many players are in it (Lacerda 1966, ch. XLII).

Ensemble	How many instruments
chamber group	from 2 to about 9
chamber orchestra	from 10 to 25 or 30
symphony orchestra	from 30 to 100 or more

The borders are not laws. A group of 28 players can call itself a chamber orchestra or a small orchestra, and nobody is wrong. What the table shows is the order of magnitude, and that changes the way the music is written and played.

Chamber group

A chamber group brings together two to about nine instruments, alike or different, and the music written for it is chamber music. The name comes from chamber, a room: music for a small space, played by a few. The group is named after the number of players (Lacerda 1966, ch. XLII):

Players	Name
2	duo
3	trio
4	quartet
5	quintet
6	sextet
7	septet
8	octet
9	nonet

The number alone does not say which instruments they are. So the names usually come with a qualifier, and some have become fixed line-ups with plenty of repertoire:

• string quartet: two violins, viola and cello;
• piano trio: piano, violin and cello;
• wind quintet: flute, oboe, clarinet, bassoon and horn. The horn is brass, but it joins the quintet because it blends well with the woodwinds.

In a chamber group each player has their own line, and nobody doubles it. In a string quartet a C major chord can be split note by note: the cello on middle C, the viola on the G above it, the second violin on E and the first violin on the higher G.

Hear the passage

Each note is an instrument. If one is missing, the chord loses a note. That exposure is what gives chamber music its character of a conversation among a few.

Chamber orchestra

Past about ten instruments the group is already a chamber orchestra, which runs up to 25 or 30 players (Lacerda 1966, ch. XLII). The deeper difference is not only the number: in an orchestra the same line is played by several players at once. The first violins stop being one violinist and become a group, a section. Many chamber orchestras are strings only, sometimes with a few winds in pairs.

Symphony orchestra

The symphony orchestra runs from 30 to a hundred players or more (Lacerda 1966, ch. XLII) and brings in all three families of instruments whole. In the orchestral score Lacerda reproduces, the woodwinds come in pairs: two flutes, two oboes, two clarinets, two bassoons, with piccolo, cor anglais and contrabassoon as extra instruments. The brass are four horns, two trumpets, three trombones and a tuba. The percussion brings timpani, triangle, cymbals and bass drum, and there are also harp and piano (Lacerda 1966, ch. XLII).

The strings are the majority. One violin sounds much softer than a trumpet, and it takes many violins to balance the winds. That is why a large orchestra has dozens of strings and one or two of each wind.

Where the orchestra sits

The layout Lacerda draws is the most common one (Lacerda 1966, ch. XLII). The conductor stands at the front, and the orchestra fans out in front of them:

1. Closest to the conductor, the strings: first and second violins on one side, violas and cellos on the other, the double basses behind them. The harps sit near the strings.
2. In the middle, the woodwinds: flutes and oboes in the first row, clarinets and bassoons behind.
3. Behind the woodwinds, the brass: horns, trumpets, trombones and tuba.
4. At the back, the percussion.

The order runs from the instruments that sound softest to those that sound loudest. The violins, which need to be heard as a group, are at the front, and the brass and percussion, which would cover everything else, are at the back. Not every orchestra follows the drawing to the letter: some conductors split the first and second violins, one on each side, so the two lines are heard apart.

Symphony or philharmonic?

Both names appear on orchestras of the same size, and the difference is one of history, not of music. A philharmonic was originally a society of amateurs, or an orchestra kept by companies or groups of people on a non-profit basis; a symphony orchestra was a professional one, funded by the state. That distinction vanished in the twentieth century, and today both names designate professional orchestras (Med 1996, ch. XXXVII).

Band

For Lacerda a band is an orchestra of winds and percussion only, without strings (Lacerda 1966, ch. XLII). It is the group that plays in the bandstand, marches in parades and leads processions: the town band, the marching band, the concert band, which is the size of an orchestra.

In everyday use the word has spread. A rock band has electric guitar and bass, which are strings, and nobody calls it anything else. Lacerda's definition describes the traditional band, the wind band, and that is the band scores for band are written for.

Who leads, and who plays what

A large ensemble needs someone to set the tempo, balance the sections and decide the interpretation. That is the conductor, also called the maestro. Just below the conductor is the concertmaster, the first violin of the orchestra, who leads the strings and may stand in for the conductor (Med 1996, ch. XXXVII).

Each player's part, the extract of the score with their own line, uses a few words to say how many should play (Med 1996, ch. XXXVII):

Word	What it asks for
solo	a passage for a single voice or instrument, accompanied or not
tutti	everyone plays again
divisi (div.)	the section splits into smaller groups, each with its own note
a 2	the same line played by two instruments

Divisi is what lets a section play a chord. The first violins, who normally play one note, split in half and play two.

What comes next

Voices also form ensembles, and the largest of them, the choir, is organised by voice type the way the orchestra is organised by family. And for so many players to perform the same work, someone has to see every line at once: that is what the score is for, with each instrument on its own staff, in the order of the families.