Yamaha PSR-275 Owner's Manual - Page 54

MIDI Functions The PSR-275/273 is MIDI-compatible, featuring MIDI IN and MIDI OUT terminals and providing a variety of MIDI-related controls. By using the MIDI functions you can expand your musical possibilities. This section explains what MIDI is, and what it can do, as well as how you can use MIDI on your PSR-275/273. What Is MIDI? No doubt you have heard the terms "acoustic instrument" and "digital instrument." In the world today, these are the two main categories of instruments. Let's consider an acoustic piano and a classical guitar as representative acoustic instruments. They are easy to understand. With the piano, you strike a key, and a hammer inside hits some strings and plays a note. With the guitar, you directly pluck a string and the note sounds. But how does a digital instrument go about playing a note? Acoustic guitar note production Digital instrument note production L Tone Generator R Sampling (Electronic circuit) Sampling Note Note Playing the keyboard Pluck a string and the body resonates the sound. Based on playing information from the keyboard, a sampling note stored in the tone generator is played through the speakers. As shown in the illustration above, in an electronic instrument the sampling note (previously recorded note) stored in the tone generator section (electronic circuit) is played based on information received from the keyboard. So then what is the information from the keyboard that becomes the basis for note production? For example, let's say you play a "C" quarter note using the grand piano sound on the PSR-275/273 keyboard. Unlike an acoustic instrument that puts out a resonated note, the electronic instrument puts out information from the keyboard such as "with what voice," "with which key," "about how strong," "when was it pressed," and "when was it released." Then each piece of information is changed into a number value and sent to the tone generator. Using these numbers as a basis, the tone generator plays the stored sampling note. G Example of Keyboard Information Voice number (with what voice) Note number (with which key) Note on (when was it pressed) and note off (when was it released) Velocity (about how strong) 01 (grand piano) 60 (C3) Timing expressed numerically (quarter note) 120 (strong) GM System Level 1 "GM System Level 1" is an addition to the MIDI standard which ensures that any GM-compatible music data can be accurately played by any GM-compatible tone generator, regardless of manufacturer. The GM mark is affixed to all software and hardware products that support GM System Level 1. The PSR-275/273 supports GM System Level 1. 54