above, have been used. The first PCM digital sampler for musical production in Japan may be Toshiba's LMD-649, created in 1981 by engineer Kenji Murata for Japanese electronic music band Yellow Magic Orchestra, who used it for extensive sampling and looping in their 1981 album Technodelic. The LMD-649 played and recorded PCM samples at 12-bit audio depth and 50 kHz sampling rate, stored in 128 KB of dynamic RAM. The LMD-649 was also used by other Japanese synthpop artists in the early 1980s, including Chiemi Manabe and Logic System. Elements Interface Usually a sampler is controlled by an attached music keyboard or other external MIDI controller or source. Each note-message received by the sampler accesses a particular sample. Often multiple samples are arranged across the keyboard, each assigned to a note or group of notes. Keyboard tracking allows samples to be shifted in pitch by an appropriate amount, typically in semitones and tones. Each group of notes to which a single sample has been assigned is often called a "keyzone", and the resultant set of zones is called a keymap. For example, in Fig 1, a keymap has been created with four different samples. Each sample, if pitched, should be associated with a particular center pitch. The first sample (Violin G#2) is distributed across three different notes, G2, G#2, and A2. If the note G#2 is received the sampler will play back the Violin G#2 sample at its original pitch. If the note received is G2 the sampler will shift the sample down a semitone while the note A2 will play it back a semitone tone higher. If the next note (Bb2) is input the sampler will select the Violin B2 sample, playing it a semitone lower than its center pitch of B2. In general, samplers can play back any kind of recorded audio. Most samplers offer editing tools that allow the user to modify and process the audio and apply a wide range of effects. This makes the sampler a powerful and versatile musical tool. Hierarchy A sampler is organized into a hierarchy of progressively more complicated data structures. At the bottom lie samples, individual recordings of any sound, recorded at a particular sample rate and resolution. While a common sound to sample is a musical instrument being played (e.g., a pianist playing a piano note or an organist playing a pipe organ), a sample could be any sound,