Most troubles with going flat can be traced to improper breathing and breath support.
They need to LISTEN and blend, and sing quietly.
One thing to keep in mind is that amateur (and even a lot of experienced) singers do not reeally know when they go flat - they don't have a visceral sense of what that IS. So if you're not careful, it becomes a bogeyman that drags every rehearsal down. In other words, you spend the whole time harping on something they are not even experiencing.
My first reading is that you have a score in e-flat minor (mine and both autographs are in d minor) and that Mertens sings in c-flat minor: this can't quite be correct, can it? I haven't searched yet, but is that performance online somewhere? Never mind, I was imagining you wrote "Komm süsses Kreutz"! Mertens sings KsT in 'g-sharp' minor, a perfect forth below Chorton c minor, a suitable transposition for a low voice. Or maybe that's 415 a minor ;-)Klaus Mertens even sings Komm Susser Tod a major 3rd lower than what is written (with original key in Eb on my score).
While accomplished organists, such as Bach, could easily transpose their part in compensation for large tuning disparities, woodwind instruments and their players were less flexible. Their fingering system limited them to playing in keys with no more than a few sharps or flats, so professional woodwind players often carried two instruments, one pitched at Kammerton and another a half step lower, in order to play in more distant keys.
String instruments were also quite sensitive to the variability of pitch heights. When asked to tune up to match the organ or tune down to match the woodwinds, the responsiveness and tone of individual string instruments could change dramatically and unpredictably. As a result, the most mobile of string players in Bach’s time probably owned more than one instrument in order to accommodate both high and low pitch centers.
Therefore, whenever Bach was leading the performance of a cantata, someone was probably either selecting an alternate instrument or transposing their part. For example, vocal parts could be notated at either the Kammerton or Chorton standard, and when Bach was in Weimar, it was simpler for him to notate the voices with the organ and ask the strings to either tune high or transpose their part. In contrast, it was more common in Leipzig for Bach to write voice and string parts at Kammerton and ask the trumpets and organ to play their Chorton parts a whole step lower.
Bach was surely aware of the fact that the transposition of two or three half steps could have a disastrous effect on his singers. During composition, Bach would have carefully considered the tone qualities of the different vocal registers in order to avoid audible breaks from chest to head voice. Similarly, he would have guarded against an upward transposition that would transform a high tenor part into one for countertenor. It seems highly likely, then, that Bach had a reference pitch in mind.
This is somewhat true; however, it is also the case that church music singers might well be required to transpose music down a whole tone to match Kammerton (if notated in Chorton) or, vice versa, to transpose music up a whole tone to match Chorton (if notated in Kammerton). And, yes, the resulting pitches would be a half tone away from our modern idea of pitch, owing to the approximate A=416 Kammerton and A=466 Chorton standards.I would imagine that a more in-depth study and comparison would yield similar results. In essence, the musicians are still performing the work in the same key that we see, but they heard what we would call a half tone lower (for Kammerton) or higher (for Chorton).
Especially noticeable when it follows a naturally tight and focused vowel like 'oo'. For example, with "cum sanctis" the 'ah' will tend flat.
My own understanding has always been that the use of C and Db flutes and piccolos arose from the relative difficulty of playing instruments with simple fingering (rather than the modern Boehm mechanism) in more extreme keys (and particular with many flats)
...
I suspect that the use of Bb and A clarinets in orchestras also originated in the difficulty of playing in more extreme keys with pre-Boehm instruments, although I have come across references to the darker tone colour of an A clarinet. I've never seen a wind band part for an A clarinet, but then as you say wind band music tends to be in flat keys.
In the case of D-fat piccolos
To participate in the discussions on Catholic church music, sign in or register as a forum member, The forum is a project of the Church Music Association of America.