In the ideal prostopinije sound, the dialog of the liturgy takes place around a consistent, comfortable pitch, so that the entire service acquires a unity that can be heard and felt through the music. This requires a certain basic ability on the part of the congregation, and especially the cantor, to hear a pitch and respond appropriately. This ability is called pitch matching.
Singing in unison and in octaves
If all the singers have the same sort of vocal range – for example a group of men or women, none of whom have exceptionally high or low voices – it is quite possible that they can sing together in exactly the same pitch. This is called singing in unison. The slight differences in timbre in each voice give a richer and fuller sound to the liturgical singing.
On the other hand, if men and women are singing together, they can achieve the same sort of effect by singing the "same" note an octave (or even two octaves) apart. Remember that if two pitches are separated by the interval of an octave (listen) they are perceived by the ear as effectively the same sort of pitch. This is called singing in octaves.
Of course, each singer still needs to listen to the others, and match their pitch, either in unison or an octave or two up or down; and the cantor needs to do the same with the clergy's pitches. You can use the Theta Music Trainer game Vocal Match to practice singing back a pitch that you hear, in your own range. Note that this game is hard; you will need to sing fairly loudly, and with as little vibrato (wavering of pitch) in your voice as possible. But this is an excellent way to develop facility with pitch matching.
Of course, it's not enough to simply match the pitch you hear; it is also important to maintain this pitch while singing. Good posture and breath control will enable you to keep your pitch from dropping over time. For cantors, try this exercise: pick a comfortable tonic pitch to begin singing the Creed (Symbol of Faith), and sing it through to the end. Then check your pitch and see whether you have gone sharp or (more likely) flat, and by how much.
You can also use the trick of very quietly humming the tonic (key) pitch, or your next starting pitch, while listening to the singing of the clergy.
Matching pitch with high- or low-singing clergy
If you as a cantor are singing with clergy whose vocal ranges differ greatly from yours, you may be able to simply sing in octaves with them. But if, for example, the priest sings lower than you do, but not so low that singing in octaves works, you can use the special properties of perfect fourths (listen) and perfect fifths (listen) to find a good pitch for the congregation.
Normally, when singing responses to litanies such as the Litany of Peace, the first "Lord, have mercy" response starts a perfect fourth lower than the priest or deacon's ending pitch:
But perfect fourths are magic; if you choose a tonic pitch a perfect fourth above the priest or deacon's pitch, the two scales will be compatible, and the resulting responses will make musical sense:
In this case, your first "Lord, have mercy" response will start on the exact same pitch as the priest or deacon rather than a perfect fourth lower; and the second "Lord, have mercy" will start a good bit higher. In fact, the clergy may not need to change their singing at all. In other words, thinking of the clergy's ending pitch as so (or sol) can help you sing in your own range.
If the priest or deacon sings higher than you, but not a full octave high, use a tonic a perfect fourth lower than his, and start your first "Lord, have mercy" a perfect fourth lower than that (two perfect fourths in a row):
Finally, if the deacon is quite a bit higher than you, there is one more trick to try: imagine that the deacon's ending pitch is on so rather than do, so that you are dropping a perfect fifth to find your own tonic. This means that your first "Lord, have mercy" will start on a pitch exactly an octave below the deacon's ending, making it very easy to find. As an added benefit, the deacon's voice will sound like a trumpet call, and will likely raise goosebumps among the congregation:
But be sure to practice this with your deacon or priest; when some clergy hear the cantor adopt a new pitch, they may try to adjust their own singing up or down to "help you out."
Pitch matching for cantors - summary
Sing in unison or octaves with the clergy whenever possible.
Otherwise, if the priest or deacon's pitch is:
- somewhat low, select a tonic a fourth above his.
- somewhat high, select a tonic a fourth below his.
- very high, select a tonic a fifth below - but practice this in advance with the priest or deacon.
What if the clergy don't have a consistent pitch?
Sometimes the clergy sing on consistent pitches as individuals, but don't agree among themselves. Work with them to find an accommodation, or choose one of the pitches and stick to it. (This may vary from one part of the service to another; for example, you might use the deacon's pitch consistently for litanies.) It is good to be able to keep the same tonic throughout the service if possible, but it is more important that the singing at each point in the service sound decent.
On the other hand, if a priest or deacon can't keep a consistent pitch, the cantor should pick a pitch that sounds reasonable and stick to it. In doing so, he or she can establish a point of stability for the people's singing, even if the priest or deacon is tone deaf.
Pitch matching for readers
When you read the epistle or other Scripture, it is nice but not necessary to adopt the priest, deacon, or cantor's pitch for your reading. But when you sing the psalm verse(s) at the prokeimenon or Alleluia (a task usually assigned to the reader), you should normally chant them on the tonic pitch corresponding to the prokeimenon or Alleluia.