Technical considerations in hymn composition II: Melody
A note about my hymn melodies: I like them to have motivic unity, meaning small melodic fragments are repeated and altered. My hero in LDS hymn writing is Alexander Schreiner and he gave us some truly masterful examples. Have a look at Thy Spirit, Lord, has stirred our souls. There are three phrases (not the usual four!) with exactly the same rhythm, made up of two halves, the first featuring two falling thirds, the second one a step lower, and then a short scale up and down. The second phrase is the same as the first, only higher. The third phrase is back down in the range of the first, but partly inverted, with rising seconds instead of falling thirds and then the scale up and down, this time returning all the way down to the starting note. This is an exceptionally tight melody, very economical in its motivic material, but that material is interestingly and masterfully varied throughout. In memory of the crucified is another good Schreiner example, four phrases made of scales that rise a fourth and fall back (the third phrase is an exception in that it leaps instead of stepping through the scale, but it’s still a rise of a fourth that is followed by a scale down). Not all good melodies are so economical, but all good melodies do involve a satisfying mix of repetition and variation. One happy result of good construction is that it makes the melody logical and more easily learned and remembered.
The rhythmic construction of a hymn is supremely important in matching and enhancing the text. Scott loves unusual constructions and rhyme schemes, so this leads to some unusual melodic structures. The rhythm is usually the first thing I settle on: what metre will suit this hymn? (I try out several.) Are there points in the poetry that should be emphasized with longer time values? Here is where you let the text lead you very directly.
Technical considerations in hymn composition III: Harmony and Voice Leading
Although I strive to keep things simple, my harmonic language is often more adventurous than most Latter-day Saints will be used to. I love lots of rich four-note chords; I love suspensions; I love seventh chords and I especially love the major triad with an added ninth (in any inversion). I love the minor mode and a much higher proportion of my hymns are in minor than what we find in the current LDS Hymnbook. I find V-I cadences dated and usually avoid them (a personal bias, admittedly). In fact, many of the hymns in this book end on a chord other than the tonic, or modulate to a different key altogether from the start of a verse to the end. I love the “reverse plagal” cadence (I-IV) in The Laborer Is Worthy and hope in performance it is left as it stands, resisting the temptation to add the tonic E-flat chord at the end. Many medieval compositions ended this way, before the V-I cadence became the norm; I find it somehow very appealing.
My melodies often hearken back to folk song and their modal tendencies (for example, mixolydian or pentatonic tunes). Perhaps this is related to the years I spent conducting and arranging for an Irish choir. I love the folk songs of the British Isles, which are the seed bed for so much American folk music. Such melodies are structured quite differently from European classical melodies, and this makes for some unusual harmonic progressions and voice leading. For example, there is an important commandment about four voice writing which every harmony student learns: thou shalt not have two voices move in parallel octaves or fifths. While I do avoid parallel fifths, I’m not so fanatic about it as some other composers I’ve talked with. I let my ear be my guide. Sometimes I justify fifths because they involve the third and seventh of a seventh chord; sometimes I purposely desire the parallelism; sometimes the solutions for avoiding them diminish the beauty of the progression, so I leave them in. Always the result sounds pleasing to my ear, which is ultimately all a composer can or ought to go by.
from the Forword to Hymns of Light
 This is true of all music in some way or other, not just hymns and songs, so I’m not revealing any astounding insight into music theory here, but it is something all composers do either consciously or intuitively – usually a combination of both.
 That chord is most satisfying on the IV chord, or on the tonic (but not the final tonic chord) and appears in practically every hymn I wrote for this collection.
 And it’s a good rule in traditional harmony, because parallel fifths and octaves generally sound bad. This is because the ideal in this style is to have the four voices be independent while they intertwine pleasingly. Octaves and fifths are such an acoustically “strong” interval (meaning that the frequency ratios are very simple, 2:1 and 3:2 respectively) that when two voices move in parallel octaves or fifths to two other notes of the same interval, the voices sound like they are tied to one another and not independent. Subtle perhaps, but quite noticeable. Kind of like a bad fashion combo. Fulfills the basic requirements of clothes, but is not aesthetically pleasing.