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  • The Master Instrument - The Piano

    The piano is a percussed string instrument played on a keyboard. Pressing a key on the piano's keyboard causes a felt-covered hammer to strike steel strings and a damper pad lifts. As long as the key is pressed, the string continues to vibrate. When the key is released, the damper touches the string and stops the vibration. String vibrations are amplified by a wooden sounding board. The sound volume and timbre of a piano is determined by the length and quality of the the strings, the percussive speed and strength of the hammers, the size and quality of the sounding board, the interaction of sound waves of different frequencies and by the sound radiation characteristics of the piano body and lid. A Concert grand is the largest piano with a large lid that is lifted for performance. The lid surface reflects sound waves toward the audience.

    The piano keyboard makes music composition quite obvious. The piano is tuned so that the sound of intervals in different octaves is more or less equivalent. Electronic versions of the piano keyboard have been connected to a variety of devices that follow piano conventions and add flexibility that the piano does not allow.

    Scales are patterns of single semitone and 2 semitone intervals. The piano keyboard divides each octave into 12 intervals known as equal temperament. The grand piano has 88 keys from A0 to C8; middle C is C4 ( counting up from the lowest C=1). A4 is known as the concert pitch = 440 HZ. My electronic keyboards have 61 keys and middle C is C3. The midi note number for middle C is 60, no matter what keyboard you are using.

    Middle C is written one tone below the treble stave and is often the first note that a student learns to recognize and play on the piano.

    Frequency = 262 (261.63) Hz

    It is the mix of frequencies that make natural and musical sounds complex. In the first analysis, a sound made by an instrument has a fundamental frequency that allow us to say it is, for example, C4 on piano. In addition, there is a mix of other frequencies or harmonics that give the sound its timbre. A vibrating string in the piano changes its harmonic structure from the moment it is struck until the string stops vibrating. Its fundamental frequency remains more or less the same, but the timbre varies.

    Piano Scales

    The keyboard is arranged so that the interval between adjacent white and black keys is one semitone. There are two exceptions to the white to black sequence -- B to C and E to F -- both are white-white semitones. A whole tone is 2 semitones. You can understand all scale structures on the piano by starting with the root note, middle C.

    If you play all the white keys on a piano C, D, E, F, G, A, B, C you have a C major scale. The sequence of semitones is 2,2,1,2,2,2,1. Each note in a scale can be named with a roman numeral I, II, III, IV, V, VI, VII. The same notation is used to describe chords based on the scale notes.

    The C minor sequence is C,D,Eb,F,G,Ab,Bb,C. As semitones, the minor sequence is 2,1,2,2,1,2,2.

    Scale sequences are also described as modes. If you stay with the white keys on the piano, you can play all the modes by starting on different tonic notes. Modes are described by names from ancient Greece: The Ionian mode starts on C and is the C major scale. The Dorian mode is all the white notes between two Ds. The Phrygian mode starts on E; the Lydian mode on F; the Mixolydian on G; the Aeolian is the natural minor scale that begins on A; and the Locrian on B.

    Digital Pianos

    The development of electronic pianos using digital sampling led to a full appreciation of sound production nuances found in the best grand pianos. The earliest piano simulations began with a small sets of samples that were played at different pitches to achieve the sounds of a full keyboard. While this was an efficient use of limited sampling memory the pitch-altered sounds were less than convincing to sophisticated listeners. As sampling sophistication and digital memory capacities increased, digital pianos became better, less expensive and more portable than real pianos. Added features included pedal controllers, weighted keys, and MIDI interfaces. Now, each piano string vibration is sampled under different key press and hold conditions; additional samples emulate sympathetic resonance when several keys are held together, and other samples record decay resonances after key release. MIDI enabled pianos can play themselves using compact MIDI files, with libraries of compositions collected on a single CD disc.

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