Writing a descant
1 Before you start, consider whether the final verse of the text to which you intend the descant to be sung is suitable for such treatment.
2 The tune needs to be well-known to the congregation, otherwise any descant will put them off their stroke. A descant should enhance the sense of worship, not cause confusion.
3 If you are intending to change the usual harmonies of the hymn, be quite sure that you are not over-reaching yourself and over-estimating the ability of the congregation to sing the main melody against both changed harmonies and a descant.
4 A good descant will have a melodic structure which is pleasing in its own right. It is not just a succession of high notes.
5 A descant can introduce rhythmic features not in the melody. For instance, many Long Metre tunes are rhythmically uninteresting, and a descant can, with the judicious use of quaver movement and/or dotted crotchets followed by quavers, add considerably to the effectiveness of the tune.
6 The descant can start in unison with the melody and branch out on its own after the initial few notes or even the first phrase. Indeed this will give the congregation added confidence.
7 Alternatively the descant can begin a few beats after the main melody, though this normally requires a shortening of the text for the phrase in question, and it is important to check that the text can bear such treatment. If so, this can be very effective.
8 A descant does not need to be fiendishly high. It is wise to treat top G or Ab as your highest note. An A will stretch some sopranos too far, and a top Bb is absolutely to be avoided.
9 Ideally a descant will lie above the melody, because if it goes below the melody what may look good on paper might well prove inaudible in practice.
10 One or two really high notes will be more effective for not being surrounded by several other high notes. Keep the tessitura of the descant at a reasonable level. As a general rule, do not let your descant get more than an octave above the melody at any given point.
11 The descant should not cause consecutive fifths or consecutive octaves with either the melody or the bass. This needs careful checking. With some tunes, it seems very hard to avoid these problems. If they cannot be avoided, it might be wise to give up on a descant for that tune.
12 Try out your descant with your choral singers in enough time to make changes if you realise there are problems. A descant is always an optional extra, and should always add something to the singing of the hymn, not detract from it. In the end, the hymn will survive perfectly well without your new descant!
© John Barnard 2012