Choral arranging is the set of decisions that turn a tune into music a specific choir can learn. The tune may already exist as a hymn, a folk melody, or a line you wrote. Arranging is not the same job as composing that tune, and it is not the same job as engraving a finished score in a notation editor. You decide who sings the melody, what the other parts do under it, where the choir breathes, and which chord arrives on the word people already know.
Those decisions are musical and practical at the same time. A soprano line that sits on a high F for six beats will thin the section before the refrain. A bass line that only stamps roots will make the harmony obvious and the rehearsal dull. The arrangement is ready when the people in the room can learn it. A page that looks full is not the same thing.
Start from the choir in the room, not from an ideal SATB
Name the forces before you write a single alto note. A Sunday choir of twelve, with two tenors who share one comfortable fifth, is a different instrument from a forty-voice concert choir. Write for the group that will stand up this month. If the tenor section is really one confident voice and one cautious voice, do not park the tenor on a high F because a textbook tenor can sing it. Give that part a line the cautious singer can find, and let the confident singer carry a descant only where the text needs it.
Decide the job of the piece in one sentence. A processional needs a tune the congregation can still recognize while they walk. An anthem can afford a longer introduction and a quieter verse. A rehearsal warm-up should be short enough to finish. That sentence governs range, texture, and how often you repeat a phrase. If you cannot say what the choir is supposed to accomplish with the song, you will arrange the whole thing at one intensity and then wonder why the last page feels like the first.
Also decide what you are allowed to arrange. A public-domain hymn and a copyrighted chorus are different jobs. CantuStudio does not create a license, and neither does a clean SATB draft. If you do not know the rights, stop before you print parts and hand them out. The musical work below assumes you already have the right to make the arrangement.
Give the tune a home, then give the other parts a job
In most church SATB the soprano carries the melody, because that is the line the congregation already hums. Keep it there unless you have a reason to move it. A reason looks like this: the verse is low and the altos will sing it more securely, or you want the men to state the tune once so the women can answer. Moving the melody every phrase, just to be interesting, makes the choir hunt for a tune they already knew. Say out loud, at each entrance, which voice has the melody. If you cannot tell, the listener will not be able to tell either.
The other three parts need jobs, not filler. The bass tells the harmony. On the first beat of a phrase, a root or a clear inversion does more for the choir than a clever passing tone. Alto and tenor connect the chords. Their best default is stepwise motion, with a leap only when the chord actually changes color. If the alto is a chain of repeated notes while the soprano does all the singing, the alto section will drift. Give them a small shape: a neighbor tone into the cadence, a step up when the text lifts, a rest when the soprano needs to be heard alone.
Unison and two-part writing are arranging tools, not failures of four-part skill. A refrain that opens in unison and then opens into SATB on the second line gives the choir a place to lock pitch before the harmony gets busy. A verse for women in two parts, with the men entering only at the cadence, is often more moving than a thick chord on every syllable. Texture is a form decision. Use four parts where the text is public and strong. Thin the texture where the text is private.
Range, spacing, and the notes a section will actually hold
The range check in CantuStudio uses a wide window: soprano C4 to D5, alto F3 to C5, tenor B2 to G4, and bass E2 to D4. That window is the edge of what the draft is allowed to print, not the band you should live in. A volunteer soprano section is happier when most of the line sits between E4 and D5. Altos are happier between A3 and B4. Many tenors speak clearly from E3 to D4 and only visit G4 as a short peak. Many basses are reliable from A2 upward, and a low E2 is a solo color, not a section note you can hold under a verse.
Spacing is the other half of range. Keep soprano and alto within an octave of each other, and alto and tenor within an octave, so the upper three voices sound like one choir rather than three choirs in different rooms. Tenor and bass may sit farther apart. A chord with a wide gap between alto and tenor sounds hollow even when every note is a chord tone. Close that gap before you add a passing tone. If the soprano is high and the alto is low, the chord is already shouting. Bring the alto up, or bring the soprano down an octave for a verse, before you blame the singers.
Divisi is a last tool, not a first one. Splitting the soprano so that half of them sing a descant only works when you truly have two groups who can hold a part alone. A choir of eight cannot donate three sopranos to a descant and still sing the hymn tune in tune. Write the descant as optional and print the melody in the same staff so a small Sunday does not collapse. The same rule applies to a bass divisi on the last chord. A low fifth under the root is a nice color when six basses are present. With two basses, it is a coin flip.
Text, breath, and the shape of one phrase
Arrange the sentence, not the bar. Mark the breaths where a speaker would breathe, then make the harmony change agree with those breaths. A chord change in the middle of a word, or a rest that slices a phrase in half, will sound wrong no matter how correct the voice leading is. If the line is "how sweet the sound," the harmony can move on "sweet" and on "sound." It should not move inside "sweet." Write the text under the soprano first, even in a sketch, so you can see the syllables before you decorate the alto.
Repeated notes are a text problem as much as a vocal one. A run of quarters on one pitch is easy to sing and hard to shape. Use it when the text is a list or a drumbeat. Break it when the text is a plea. A step away and back, or a rest that lets the consonant land, gives the section a reason to stay together. The bass can repeat a pedal for a phrase if the pedal is the point, as in a drone under a verse. Do not let every voice pedal at once. Someone has to carry the sentence.
Dynamics and tempo live in the arrangement even before you write a hairpin. A verse that sits lower, with closer spacing and more stepwise alto and tenor, will sound quieter without a piano marking. A refrain that lifts the soprano, opens the bass by a fourth, and puts the choir back in four parts will sound like an arrival. If you need a fortissimo to make the refrain feel like a refrain, the notes are not doing their job yet. Fix the tessitura and the texture first. Then add the marking so the choir knows you meant it.
Key, cadence, and the one place the arrangement must turn
Pick the key for the weakest section, not for the piano. If the basses lose the low notes and the sopranos are already high, the key is wrong even if the melody looks familiar. Transpose before anyone memorizes the old key. A semitone is often enough. Sing the highest soprano note and the lowest bass note in the new key before you commit. If either one is a grimace, move again. The harmonization guide walks through how the bass and the cadence behave once the key is chosen. This page only insists that you choose it on purpose.
Every arrangement needs one cadence the choir can feel coming. In a hymn that is usually an authentic cadence, dominant to tonic, with the soprano arriving on the tonic by step and the bass arriving on the root. You may approach it with a IV or a ii, and you may color the dominant with a seventh if the choir can tune it. What you should not do is surprise the last chord with a chromatic slide nobody has heard in the verse. Save the one surprising harmony for a word that deserves it, and then resolve in a way the section can find in the dark.
Modulating for a whole refrain is a large decision. It works when the text itself turns, and when you have time to prepare the new tonic with a pivot the basses can sing. A truck-driver lift of a semitone, with no preparation, is a pop habit. It can be thrilling once. On the third stanza it is a tax on the tenors. If you modulate, write the way back, or end in the new key and mean it. Do not modulate and then pretend the original key is still home.
From a draft on the screen to a rehearsal you can run
A useful order is tune, key, bass, inner parts, parallels, text, then playback. CantuStudio can draft soprano, alto, tenor, and bass from a melody and keep that melody in the soprano. Treat the result as a first pass. Listen before you send it. Mute one voice and ask whether that singer could find the next note without the piano feeding it. If the alto only makes sense when the soprano is loud, the alto line is not finished. The voice-leading guide and the parallel-fifths guide are the review you do before the choir learns a mistake.
Export only what you have already heard. PDF is the page someone prints. MIDI is the practice file a singer can loop. MusicXML is the score you keep editing in MuseScore, Sibelius, Dorico, or Finale. The MusicXML download is a Pro feature. A free account does not receive the .musicxml file. Prices and the free monthly limits live on the English pricing page. Do not promise the choir a stack of new pieces until you have checked those limits. The choir-director tool and the SATB arrangement app are the same drafting loop from the product side. This guide is the musical checklist those pages assume.
In the room, teach the cadence and the tune before you teach the decoration. Have each section sing its line on a neutral syllable once, then with the text, then with the other parts. If a bar falls apart, it is usually a leap, a parallel that fused two sections, or a breath in the wrong place. Fix that bar in the file the same day, so next week you are not rehearsing the version you already rejected. An arrangement that changes after the choir has memorized it is more expensive than an arrangement that took one extra evening at the desk.