We received a query whether the automatic organ quoted in norm 71 of Pius XII’s De musica sacra is the same as today’s portable organ, or electric keyboard, or electronic organ, or digital keyboard.
The short answer is no. The key to understanding this answer is twofold. First is language. Unless a Roman document was issued in a language other than Latin, or its basis was explicitly declared to have been in this or that language, the first linguistic recourse we must run to in order to understand a Latin neologism is Italian. The Latin autoorganum is a calque of the Italian auto-organo, and this is an instrument that mechanically reproduces music from a sound roll. An example is below, a Barbieri double-roll automatic organ, and a whole lot more is here.
Second is the classification. The list covers instruments that record or play recorded audio by themselves. A phonograph records and reproduces sound mechanically. The radio, on the other hand, utilises radio technology, which collects sound from one location, transmits it as information across space via radio waves, and reproduces it mechanically in another location through a receiver, which is the device we call radio. Tape recorders collect sound, store it in a magnetic tape, and play the sound back mechanically. Wire recorders function in the same way, only that they store sound in a steel wire. (The Latin uses dictaphonium and magnetophonium, whose Italian equivalents dittafono and magnetofono are really just tape recorders.) These devices can only play sound mechanically after immediate human effort has been expended at recording and storing the sound.
While portable organs come with prerecorded music, playing the recordings is by no means their sole capability. What sets them apart automatic organs is their capability to mimic the sound of the pipe organ, and produce sound real-time, with the guiding hands of a pulsator. In short, sound is not merely reproduced mechanically, but rather produced presently contingent upon human art and skill, though in a limited ambit only. In reality, though, digital keyboard is an umbrella term that includes electronic organs, and electronic organs are specifically permitted as temporary substitutes for the pipe organ, in norm 64 of the same Pian instruction.
This is by no means an apology for the continued use of portable organs, or for the mandatory use of any musical instrument whatsoever in the Sacred Liturgy. A majestic pipe organ, tuned and primed to optimum performance, when the pulsator handles it in such a way that the music overwhelms and smothers the singers, deserves to be silenced forthwith, and the pulsator retrained. It is the constant teaching of the Church that Her music is, first and foremost, purely vocal. Thusly St Pius X establishes in norm 15 of Tra le sollecitudini. For what is an organ, but merely a copy of our vocal apparatus, the organ of the voice, the organum vocis, a long pipe connected to a mouth that, when air passes through it, produces sound.
Ut in omnibus laudetur Dominus.