Interval Mirror Point
The Intervallic Mirror Point is a compositional technique developed by James in 2019–20 which uses interval mirroring and inversion to generate a register-specific pitch set. The technique enables a single set of pitches to be expanded, generating a wide variation of pitches across an instrument's range which become set in their register. Whichever register a particular pitch appears in, it is fixed in that register. The IMP was developed in response to the register-specificity of Carson Cooman's Restarting Pitch Space, and the intervallic focus of Per Nørgård's Infinity Series. The technique combines these two components to generate material which is register-specific whilst remaining entirely focussed upon the intervals between the notes and their respective mirror or focal points, forming a coherence which links all of the pitches together.
A diagrammatic explanation of how to use the technique is shown below, as is a list of works which employ the technique.
All diagrams below credited to the composer, James M. Clay.
Figure 1: An initial pitch set is chosen first, which can be seen above. This will be the basis of the IMP register-specific pitch set.
Figure 2: The initial pitch set is then framed with focal or mirror points, on which the intervals will be inverted.
Figure 3: The intervals between the pitches of the initial pitch set and the mirror points are measured and then projected on the other side of the mirror points. Where the initial pitch set moves up by a semitone, the note in the reflected pitch set will move down by a semitone.
Figure 4: In order to create further mirrored pitch sets, the highest and lowest pitch sets are then mirrored against newly chosen mirror points. The uppermost pitch set is then mirrored upwards again, and the lowermost pitch set is mirrored downwards. This can be repeated as needed, until a suitable register-specific pitch set is generated. The diagram above shows a full register-specific pitch set in its final state.
Depending on which mirror points are chosen, the generated pitches can be widely varied or kept reasonably restrained with only minor chromatic variations. The mirror points can be freely chosen, meaning that any amount of pitch variations can be achieved. These pitches, fixed in their register, can then be used in compositions.
Research into further uses and developments of this technique is ongoing.
Compositions employing IMP
James M. Clay
Rearranging Furniture (2020) for Classical Guitar
(Utilising a microtonal IMP pitch set. An IMP pitch set which includes microtonal pitches in its initial pitch set.)
not only the birds herald the new dawn... (2020) for Bass Flute, Tape, and Live Electronics
Alma redemptoris mater [Chorale Prelude] (2019) for Organ Solo
Prelude (IMP) on 'Of the Father's Love Begotten' for Organ Solo
New works to be added soon.
Carlotta Ferrari
Recordings by organist and composer Carson Cooman of Ferrari's below works and other works are available at IMSLP.
Natale in blu (2020) for Organ Solo
Toccata e fuga IMP (2020) for Organ Solo
An der Nordsee (2020) for Organ Solo
Arquitectura vegetal (2020) for Organ Solo
See the Italian version of this page (translated by Carlotta Ferrari)
https://intervallicmirrorpoint.altervista.org/