5/4/09 Wind Instruments Source of vibration -- Edgetone • A continuous airstream • Frequency depends on – Jet speed (higher speed, higher frequency) • Resonating tubes – Gap distance (shorter distance, higher frequency) • Flute family: edgetone - air • Reed family: reed • Brass family: player’s lips Organ Pipes Organ pipe cactus Different shape: different tone color (Figure 12.14) Closed pipe: only odd-numbered harmonics Recorder How recorders work 1 5/4/09 Overblowing Transverse Flute • Increase the jet velocity – increase the • Flute player has more flexibility vibrational frequency – Change the gap distance by moving the lips or by • Higher frequency makes the pipe to resonate at rolling the instrument slightly toward or away a higher mode from the lips • A higher-pitched sound is produced • Obtain a variety of relations among pitch, loudness and timbre • Easier to control overblowing Source of vibration -- Reed Clarinet • Single reed • A cylindrical tube – Cylindrical bore: Clarinet open and one end and – Conical bore: Saxophone closed at the other • Double reed – Even-numbered harmonics are absent – Conical bore: Oboe, English horn and bassoon – Different fingering – Cylindrical bore: Krummhorn scheme Natural modes of a complete cone Saxophone • The frequencies are the same as an open cylindrical tube of the same length 2 5/4/09 Oboe English Horn • Narrow cone (compare with saxophone): rich in high harmonics, quieter sound Bassoon Krummhorn Source of vibration -- lips Tuba • Conical tubes: cornet, alto and baritone horns, and tuba • Cylindrical tubes: trumpet, trombone and French horn – Bell and mouthpiece modify the standing-wave patterns – complete harmonic series 3 5/4/09 Trumpet Trombone French Horn How a Valve changes the trumpet's Length • Thus each semitone makes instrument 6% longer Radiation Efficiency Trombone slide position • Radiation efficiency measures the percentage of the • Note the distances are not equal but increase acoustical wave energy that exits the tube through the by about 6% horn – If efficiency was zero – no sound exiting instrument – If efficiency were 100% - no sound would reflect and no standing waves would be produced • Note: Remember that standing waves are produced by two waves traveling in opposite directions in a tube or string 4 5/4/09 Radiation Efficiency for various shapes Mutes on Trumpets • Remember that a larger hole more efficient • Two effects radiation (Figure 13.24) – Cutback on overall radiation efficiency – Enhancement of higher frequencies (changes resonant frequency to higher freq) • Similar effect in French Horn by placing hand in bell Source Size • Trombone vs. Trumpet • Flute vs. Piccolo • Tenor and Soprano Saxophones • Flute and Clarinet ? • Oboe and Clarinet ? • Violin and Clarinet ? 5 .