Among recent updates to my Horn Articles Online site was the restoration to the site an article on the use of the assistant first horn. Versions of this article were published in The Horn Call 34, no. 2 (February, 2004) and also in Playing High Horn (2007, Horn Notes Edition). I took the article off the site in 2007 because of the book, but with the demise of that publication the article has been restored to the Internet. The updated version online at this time is a combination of the texts of both versions. The article begins as follows:
In high horn playing, at least in the USA, a key element is the effective use of an assistant first horn. The essential role of the fifth (“swing”) horn in a five-horn section is to assist the principal horn by taking over the first part periodically, especially during tutti passages, allowing the first horn to rest and remain fresh to comfortably perform other more soloistic, exposed passages. The first horn, if there were no assistant, would have a much harder time performing these passages with a level of comfort and freedom. In addition, certain works, when performed with a competent assistant horn, are relatively simple works to perform well, but without an assistant horn, suddenly become a grueling test of endurance for the principal hornist.
Specifics as to how the part will be divided will vary depending on the players and the literature. Some principal players favor a good bit of doubling, but in general I would recommend that there should not generally be a lot of doubling in an orchestral situation, except for especially loud, climatic moments in the music. Passages where the assistant is to play should be clearly marked in the music in logical, consistent markings. These selections should be at least roughly thought out before the first rehearsal and should be at least roughly marked in by the end of the first rehearsal. Usually the passages for the assistant to play will be marked with brackets by the principal player.
In marking passages for the assistant to play in an orchestra, the principal player should be especially attuned to changes of orchestration and texture. Whenever playing, the assistant also needs to “take the ball” and lead. Anything really exposed should find the principal horn in the “hot seat” but when the assistant is playing, they should have the part and strive to match the tone of the resting principal.
In some works it may not be possible to use an assistant due to the thin orchestration or the lack of tutti passages. If this is the case, it is better to simply let the assistant off for the work. Depending on the literature, the split between the first horn and the assistant will be something between roughly 85/15 and 60/40, with a split of 50/50 possible on light literature such as marches and pops concert material. It is important for the principal horn to be careful not to “ice the chops” of the assistant; the assistant must be given enough to play to keep fresh for their entrances. This is especially true if the markings include overlaps and “sneak-ins” without attacks.
In general there are four types of passages that I look to give to the assistant horn when I am playing principal horn: