The introduction and species chapter for the Horn will be far shorter than that for any other instrument. The reason for this is that there is only a single instrument we call the Horn. There are many variants, but all are considered the same instrument.
Double F/B-flat Horn
This is the only instrument we need to familiarize ourselves with. Horns, before the invention of the valve, used to be pitched in any key imaginable, but with the valve, these various keys went away. The most common of the instruments was the Horn in low F (sounding a fifth lower than written). This instrument was able to do nearly everything that the old natural Horns in various keys could do. However, security in the upper register was a bit suspect. To solve this problem, a second set of tubes was added to the valve F Horn that put the instrument in high B-flat (sounding a second lower). In so doing, the upper register was made easier to play. Therefore, the modern Horn is a combination of two different pitches of instrument (F and B-flat). On the whole, this single instrument is the extent of the family
The Double Horn has a huge range of nearly four octaves, which is one reason other sizes of the Horn never came into vogue. On the high end, parts have been written up to a written high E three ledger lines above the treble clef (sounding the A a fifth lower), and on the low end, I know works that use the pedal range below a written low F at the bottom of the bass clef (sounding a low B-flat a fifth lower). Generally, the upper range (up to this extreme high E) is avoided and the C a third lower is the maximum upper range. The composers who did use the extreme E only did it once in their entire career (R. Schumann and R. Strauss).
The best range for the instrument is about a two octave span from G below the treble clef to the G at the top of the treble clef. This is the most melodious and most flexible part of the Horn. It also corresponds to the range that was used by composers who wrote for the valveless Horn, because the harmonics in this region are closer together and can produce more interesting combinations.
Above this range, the sound becomes bright and piercing and is best only in forte. Below this range and the Horn gets more sluggish and cannot project as well.
An interesting factoid that few realize is that the Horn (excluding its pedal range and its extreme high range) has exactly the same range as the Bassoon. Perhaps it is for this reason, that these two instruments complement each other so well.
Mozart Concerto 1
Strauss Concerto 1
Horns pitched in solely F or B-flat are known and used by some players. The famous British horn player, Dennis Brain, is known to have used single Horn in B-flat. These horns have smaller ranges than do the Double Horn. The use of either is at the whim of the player, and will only be used for special circumstances. No special concern needs to be taken by the composer.
Dennis Brain performing on a single B-flat Horn.
Vienna and French Horns
These are two very different instruments that are used in Austrian and France respectively. The French Horn is obsolete. It was a single F Horn with piston valves with a 3rd valve that ascended rather than descending. Our modern instrument is not a “French” Horn.
A true French Horn
The Vienna Horn is still very much alive, but is only used in and around the city of its origin. Once again, it is a single F Horn (though it can be fitted with various crooks like the old natural Horn), but its valve and bore structure is quite different. Unless you know that you are composing for the Vienna Philharmonic, don’t score for the Vienna Horn.
Comparison between a Double Horn and a Vienna Horn
Vienna Horns playing the theme to Jurassic Park (The dinosaur nerd in me geeks out over this one).
There are a few other members of the Horn family, but their use is not dictated by the composer/orchestrator, but rather by the player. The main instrument here is the Descant Horn pitched in high F an octave above the standard F Horn. Just like the Piccolo Trumpet, it cannot help the player reach higher notes, but it can aid in those notes’ production. Passages that include the notorious high E, are usually played on a Descant.
Most times, the Descant is doubled with the standard B-flat side of the Double Horn. It can also be coupled with the entire Double Horn making an instrument with three pitches in one (the Triple Horn). Triples are quite heavy, and only used by select players.
Explanation of the Descant Horn
The Quoniam movement from Bach’s B Minor Mass
This is more of a novelty instrument than a usable Horn. It is pitched in high B-flat an octave higher than the B-flat side of the Double Horn (same pitch as the B-flat Trumpet). They can be found easily on eBay, but as to their use, I highly doubt that they make for practical instruments.
Demonstration of a Piccolo Horn
Over the years, several attempts to make a Horn larger than the standard F Horn have been tried. In the days of the valveless instrument, pitches down to low B-flat (sounding a 9th lower than written) were common, but these low pitches went extinct.
The famous tuba player Roger Bobo had a Bass Horn in low C constructed for his use in movie scores and his own recordings. The instrument is a massive beast that is probably best described as a tuba in the shape of a Horn. The bore structure is far too wide for what a true horn really is. Other people have tried to make their own instrument to varying degrees of success, but a true Bass Horn is still elusive.
Of all the possible brass instruments that could be made and have not been, the possibility of a true Bass Horn seems to be the most appealing. The low range of the standard F Horn has always been inflexible at best.
A recording where a Bass Horn is used in a large horn ensemble.
Roger Bobo’s instrument