When to use the F side and when to use the Bb side?

Previously, I said that you should get familiar with both sides of the horn, so that you can choose which side to use on any occasion.

But how do you choose which side to use when playing in a performance?

There are a number of things to consider

• Tuning
• Security
• Tone
• Fingering

Start with tuning. As a general rule, you want to avoid using a 5th harmonic or octaves thereof since these are flat relative to equal temperament, and you want to avoid 13 and 123 valve combinations, as these will tend to be sharp.

So, on the Bb side, that means you avoid playing an open A, or playing Ab, G or F# with 2, 1 or 12 respectively. The A can be played 12 and the Ab 23 with no difficulty, but G will be flat if played 1, and sharp if played 13. So you play the G open on the F side if possible. The same consideration puts F# on to the F side using 2. Of course, in the octave above, G can be played open on the Bb side and F# with 2. Those fingerings are fine.

In the octave below, G and F# should also be on the F side.

First space F can be played either open on Bb side, or 1 on F side. Both should be fine from a tuning point of view. E played open on the F side will be a bit flat, but will be in tune played 2 on the Bb side. The same consideration applies to Eb, D and C#.

Security - avoiding cracks and clams - will tend to cause you to want to play predominantly on the Bb side particularly in the upper register, since the harmonics are further apart on the Bb side than on the F side.

There are those who suggest that you ought to play predominantly on the F side from 2nd-line G down, and predominantly on the Bb side from Ab upwards. Personally, I don't see the need for such a hard-and-fast rule, especially as just below that transition, you come to the range E to C# which will be flat if played on the F side. Also, if you make that a general principle, then you will find yourself with quite a few awkward fingerings and poor-sounding slurs if you have a passage which takes you over the break a lot.

Tone is a bit harder to decide on. In principle, you ought to be able to produce a tone on both sides of the horn such that the audience can't tell which side you are using. If you have achieved that, then for the most part tone colour doesn't need to be a consideration. In practice, the F side does tend to produce a slightly more veiled or velvety sort of tone, a bit less brash than the Bb side. If the piece you are playing requires that, then using the F side might be a good idea, if only to put you in to the right state of mind for the piece.

As for fingering, take a look at the following excerpt from the Scherzo of Mahler 6. (You can click on the graphic to see it larger.)



Look first at Horns 1 & 2 on the top line. Under normal circumstances, you would think that this is upper register, straightforward Bb side territory, especially as the notes are D# and E which would tend to be flat on the F side. But with the grace notes like this, going from 1 on the D# to 2 on the E won't give you the quickest or cleanest possible slur. Much easier is to go from 2 to 0 on the F side. But what about the tuning? Well this is a rather brash passage, we don't want all that much in terms of subtlety here, so you can open your right hand a bit, which will have the dual effect of raising the pitch and giving you a brighter and more raucous tone, which is precisely the effect required!

Horns 7 & 8 an octave lower should use the same fingering, for pretty much the same reason.

The middle two parts are more interesting - you have more different notes to consider. But almost all the note pairs are a semitone slur up from the grace note. The same consideration applies, you want if possible to avoid having two valves going in opposite directions in the slur. C#-D is OK 23-3 Bb side, or 2-0 on the F side. Either will work perfectly well. B#-C# can also be on either side, as can B-C. For A#-B you can take advantage of the slightly flat open Bb harmonic and play this note pair 0-2 on the F side. The A# is only a grace note, it will pass so fast that nobody will have time to notice that it is a trifle on the flat side. G#-A can be played 23-3 on either side, and so on. So in fact, the great majority of these slurs are either as easy on both sides, or significantly easier on the F side, albeit occasionally with an unconventional fingering. So this part should probably also be played on the F side, even though it is in a range more normally played on the Bb side.

I'll leave it to you to work out the rest of the horn 3-4 stave and the horn 5-6 stave to see what fingerings are appropriate and which side you should play.

The key point is that even if you make a decision predominantly to use one side, you have to know both sides sufficiently well so that when a passage comes up such as the one I have described, you can switch in order to make the passage easier to play effectively.