In November 1998 I suffered a major injury to my left knee. While laid up I kept my brain active by writing some 3-part arrangements of a few SATB hymn tunes.
My first efforts along these lines arose out of necessity in 1980. The obstreperous new parish priest at the Anglican church where I was Organist and Choirmaster suddenly banned the singing of all choir anthems and solos – except for during the Communion. Faced with the need to suddenly come up with a new communion motet each week, and with myself as the only organist able to use the pedals, I solved the problem by diving into the hymnal. There was a young beginner organist in the parish. I wrote out simplified arrangements of every communion hymn in the book so he could play accompaniments on manuals only while I conducted the choir.
I kept the soprano part unchanged – for obvious reasons. I left the bass part more or less intact, only making changes if absolutely necessary. Finally I collapsed the alto and tenor lines into a single part. I aimed to make this new composite inner voice reasonably singable in itself, creating the option of teaching it to the altos in the choir to make a 2-part setting.
This 3-part texture avoids the problem inherent in transferring SATB choral writing to manuals only – by dealing in a reasonably harmonically-secure fashion with intervals greater than an octave between bass and tenor. Experienced players can collapse SATB texture for manuals-only performance at sight by using the right hand to take high tenor notes in addition to managing the alto and soprano parts, but this requires more than a beginner’s level of skill with keyboard harmony if it is to be done artistically.
Here’s one example (though it's not a communion tune) – the Passion Chorale. Score is attached.
I’ve used the Rotterdam Transept organ – the Hauptwerk Praestant 8 with just the addition of the 16-foot pedal flue by way of the master bass coupler.