Mauricio Kagel, "Acustica" (Side Two)

(continued liner notes)

Some examples:

Castanette-Keyboard with a scale of diameters from 1 4/5" to 7 1/5" which can be "tuned" by means of double-bass pegs in the action-tention (with the result that even deep-sounding castanettes will sound clearly when played extremely quickly);

two sets of Bull-Roarers (one with an aerodynamic profile, the other out of plain pieces of wood), which are wielded by hand and worked by twisted rubber band.

Nail-Violin, a form of the idiophonic friction-instrument invented in the mid-18th century, with 16 iron rods of equal width but of different lengths (between 2 1/25 and 16 4/5"; temperature 15√8) which vibrate transversally when played with a cello or double-bass bow;

Roundpeg-Violin, a version of the nail-violin (9 wooden sticks between 3 23/25" and 3'; temperature 8√9);

Scabella, clapper-sandals worn by Ancient Roman choir-leaders, but fitted with a hinge in the middle of the sole, so that the performer can achieve audible results with the minimum of effort;

Hinged-board (Crepitacolo), a flat piece of wood with various handles attached which the iron parts hit according to the force with which it is shaken back and forth (a new version of the original church bell);

five-tongued Ratchet with common crankshaft, the cogwheel frequency of which is tuned in five stages, so that the loudness of the noise can be influenced by altering the tongue-setting;

Pick-ups and Diaphragms in as many forms as possible (other than the usual ones), in order to explore the devious route to higher sub-fidelity: e.g. plastic funnel and knife-feather and ukelele, sandpaper and drawing pin, matches with and without box;

Cross-blower for the timbre-modulation of the pages of a book;

-- from Avant Garde Project