Page  395 ï~~A META-ACTION FOE Abstract: This paper outlines a portably action for the grand piano. effect, was de instruments and, temporaril3 keyboard assembly. It can be controlled f in either a performer/machine interactive features are a high degree of independenc their operational speed. Performance so these components; a control that has traditional instruments or any player pian

Page  396 ï~~into a seamless unit where all components can slide freel mounted on 5 support brackets which have adjustable fv position along the unit rails themselves and the feet can t degrees off the vertical and also raise it slightly. The acti which gives it an assembled weight of 35 Kg. On the forward rail, which faces into the instrument, a staggered rows. The length of the rail can be varied to sL adjustable from either the action feet or the individual ha a single moving part consisting of the solenoid 'plug' or the other end of a threaded rod. They are capable of oper a base of aluminium andialthough vary in size are small Covered variety materials produce ( approximately 18 mm and weighs slightly more than the The hammer solenoids receive power for very brief per 10 to 20 milliseconds. This range determines the dynami where the hammer just reaches the string and where it it that results in interference from waves returning along th On both sides of the rail which appears towards the

Page  397 ï~~Control and Performance It was envisioned that the action should remain intera interaction. Whichever way this might be achieved commercially available controller is sent to a powet the output information passed to the action perforr one of the most challenging directions in computer m In meeting the real-time demands of such an interactui a Secon Processing System (SPS) appeared ne consideration. The first, involves (or more) StW communications link. The second, requires a memory via shared memory with the main processor. Either al of hammer/damper operations, e.g. the ability to rai: being struck or leave them lowered while striking delaying strategies, where the dampers can be rem( during the natural decay of the sound, has powerful cc Control of the action is divided on a function basis, s only quite distinct but vary in control complexity. TI -\.....L%...A A--.. f...A...... /-A.--1 --1 --1 -