For this purpose we will include horns as they are made of brass, and can blend pretty well with the others, though horn players hate to be called brass! In fact there can be many situations where the horns are left out, this gives maximum "bite". Including horns will soften the bite a bit and increase total sonority and fullness.
In the modern symphony the usual set-up is:
4 horns in F
2 or 3 trumpets in Bb (use 2 unless you really need 3)
2 tenor trombones
1 bass trombone
1 tuba
Only the horns and trumpets are transposing instruments .
This is 10 instruments, arranged in the full orchestra score on 5 (6) staves thus:
Horns 1 & 2
Horns 3 & 4
Trumpets 1 & 2
(Trumpet 3 if used)
Trombones 1 & 2
Trombone 3 & Tuba
This last is almost the only case of two different instruments sharing one stave but it is customary.
Notes: trumpets and trombones are the "heavy brass" and have a brilliant, sharp sound in forte and above. Horns and tuba have a more rounded sound with less cutting edge.
If you want a loud, dominating sound, make sure that all the trumpets and trombones are used, with or without the others.
Problem
If we have four-part harmony, how do we accommodate ten instruments?
Obviously one way is don’t: just have four of them, or eight of them with doublings.
Another thing is to remember Rimsky-Korsakov’s rule: "From mf and above, two horns equals one trumpet or trombone." In modern practice we would make that f and above. So what about this:
Soprano Trumpet 1, Horns 1 & 3
Alto Trumpet 2, Horns 2 & 4
Tenor Trombones 1 & 2
Bass Trombone 3 & Tuba.
On that bass line, in fact all brass bass lines, the tuba is quite often put an octave lower than 3rd trombone. (Caution: don’t use 8va bassa for Tuba.)
Here’s another way:
Soprano Trumpet 1, Trombone 1 (8ve lower)
Alto Trumpet 2
Tenor Trombone 2
Bass Trombone 3, Tuba (8ve lower)
That will already sound good, though to this we can add the four horns, one on each voice-part. It may not work to distribute them in unison with the others, because of the restricted effective range of the horns. If this is a loud passage, keep the horn parts high, if more modest in volume, lower them. What all this comes to is that some of the horn parts may have to double the heavy brass in a different octave. The main thing is to keep the horn parts comfortable.
If you write a 4-part chord for 3 trombones and tuba alone, keep it soft. That should blend fairly well; but the tuba, being a totally different animal from the trombone, does not blend with it when played loudly. Hence, a loud tuba should either double bass trombone, or be regarded as a solo instrument, because that it what it will sound like. One other good use for the tuba is as a deep, 5th horn, for it blends well with horns.
Usage in the symphony orchestra
The first rule is not to use brass too much. Give them plenty of rests (they are used to it) and then they are more effective when they do play. The ear tires more quickly of brass sounds than of strings and woodwind.
The second rule is not to use all the brass every time. Horns can be used fairly frequently but the others should punctuate the music as and when effective. Trumpets can be used a little more often than trombones, particularly if muted, when they virtually make an extra woodwind sound. The tuba should be used least of all. Its tubby sound can be quite fatiguing to the ear. It can also fatigue the player, who needs lots of breath to play at all. Don’t expect the tuba to sustain a long phrase – he can’t. Give him short phrases or even single notes.
A final caution
Beginners all too often make a brass or horn player begin a passage on a very high note. This is dangerous because it is all too easy to hit the wrong note. Avoid the extremes of the compass anyway, but if you must use them, let the player approach them from another note not far away.
Another point is that the lowest notes of all brass instruments are tricky to produce; they are never of good quality and will "speak" only with reluctance. No agility can be expected down there; use only sustained notes.
Terry Dwyer
February 1, 2006