Editor’s Note: This is the second of the three-part series presented by Science India to explore the scientific basis of the rich heritage of Indian music
The first volume of this article embarked on a comprehensive journey through the intricate world of music, beginning with a meticulous examination of the characteristics inherent in musical sound. These characteristics serve as the foundational pillars upon which the subsequent exploration unfolds. Following this insightful discussion, the article meticulously delved into the classification of Indian musical instruments, providing a structured framework to navigate the rich tapestry of traditional music.
Transitioning seamlessly from this classification, the narrative gracefully shifted its focus to Tantu Vadya, or string musical instruments, offering a captivating exploration of these enchanting instruments. Through the scientific lens, readers gained a deeper understanding of the intricate interplay between tension, vibration, and material composition that define the unique timbres of each instrument within this category.
Building upon this foundation, the current volume continues its exploration by delving into Sushir Vadya, or wind instruments. Additionally, this volume sheds light on Avanaddha Vadya, comprising percussion instruments or drums.
SUSHIR VADYA (WIND INSTRUMENTS)
‘Sushir’, meaning ‘hole’, encompasses wind instruments (aerophones) such as Bansuri, Shehnai, and Nagaswaram. These instruments involve blowing wind into a hole to produce sound, with an air column made of bamboo, wood, or metal, featuring holes for creating different notes. Wind instruments are categorized based on the method of playing. The first type involves mechanically supplied wind, as seen in the Harmonium. The second type includes mouth-blown instruments like Shehnai and Flute, where the wind is supplied by breath. The evolution of wind instruments reveals that primitive flutes initially had two or three vertical holes, progressing over time to transverse flutes with seven holes.
- Bansuri: Single or double flutes, characterized by a solitary hollow tube and finger holes for pitch control, are prevalent across the country. In the north, this flute goes by various names such as Venu, Vamsi, Bansuri, Murali, while in the south, it is referred to as Pullankuzhal, Pillankarovi, or Kolalu. The Bansuri, a transverse alto Flute crafted from a single bamboo length, features six or seven open finger holes and holds special reverence as Lord Krishna’s divine instrument, often linked to Krishna’s Rasalila dance.
- Shehnai: Shehnai, a reed instrument, exhibits seven holes along the tube, manipulated by the player to produce melody through finger movements. Historically, Shehnai was integral to Naubat, a traditional ensemble of nine instruments found in royal courts. Classified as a mangal vadya, it is a customary presence at auspicious occasions in North India, including marriages and temple festivals.
- Harmonium: The Harmonium, a keyboard musical instrument, is frequently employed as an accompanying instrument for vocalists. Evolving from French designs, the harmonium underwent unique developments in India, incorporating features like drone stops and a scale-changing mechanism.
Clockwise from top left: Bansuri player GS Sachdev; Pandit S Ballesh playing the Shehnai; The harmonium evolved from French designs and underwent unique developments in India
Wind instruments rely on manipulating a vibrating air column within a hollow tube to create music. For example, the Bansuri or Flute, crafted traditionally from materials like bamboo or cane in India, features a closed cylindrical tube. It typically includes a larger mouth hole on the side near the closed end, distinguishing it from Western counterparts, along with additional lateral holes whose number can vary, with South Indian flutes often having eight finger holes. When played, the instrument is held transversely, with the mouth hole slightly turned outward, and the performer’s lower lip resting on its edge. Sound production involves blowing air across the mouth hole, creating vibrations within the cylindrical pipe. Manipulating pitch is achieved by adjusting the opening’s size, with flautists uncovering holes to enlarge the resonator’s opening. Larger holes have a more pronounced effect on pitch, ensuring accurate musical notes by adjusting hole sizes.
Image Courtesy: Wikimedia Commons
Reed instruments, prized for their lush and resonant tones, utilize metal or cane reeds. Examples include the reed organ pipe, a metal reed instrument, and the harmonium, also a metal reed instrument but without pipes. The Shehnai, an ancient instrument, features a single cane reed attached to a pipe, holding a unique position in Western orchestras and military bands. Clarinets, designed for various pitches, employ a single reed placed over a mouthpiece opening. The pipe, typically silver or wood, includes multiple keys for altering the air column’s length and producing different notes by activating the reed with the player’s breath.
Double reed instruments, such as oboes, have a slight variation. Two reeds bound together are inserted into a conical pipe. When air is blown into the instrument, the reeds beat against each other, alternately opening and closing the aperture. The varying pressure causes vibrations in the air column within the conical pipe, determining the resulting sound’s pitch. Ensuring tight coupling between the reed and the pipe is crucial, preventing the reeds from escaping and vibrating at their natural frequency. The tonal characteristics of these reed instruments depend on factors such as the air column, material, and shape of the pipe.
In the harmonium, hand-operated levers expand and contract the bellows, regulating airflow. This air passes over a series of reeds housed inside the instrument. Each reed consists of a metal strip affixed to a frame, free to vibrate at one end as air moves over it. Reed pitch is determined by factors like length, thickness, and tension. Longer, thicker, and tightly tensioned reeds produce lower pitches, while shorter, thinner, and less tightly tensioned ones yield higher pitches. The reeds’ design, resonance chamber dimensions, and stops shape the harmonium’s tone quality and volume. Vibrating reeds generate sound waves resonating within the instrument’s chambers, with their sizes and shapes influencing resonance characteristics. These waves are projected outward through casing apertures.
AVANADDHA VADYA (PERCUSSION INSTRUMENTS OR DRUMS)
Avanaddha Vadya denotes membranophones crafted from animal skin, prevalent in classical performances for accompaniment and solo acts. They fall into four categories based on playing techniques. The first type involves hand-played instruments like Tabla and Mridangam. The second type features stick-played instruments such as Dhol and Nagada. The third type comprises finger-played instruments like Duff and Janjira. The fourth type includes instruments like Damru, struck at both ends via a central thread.
- Dholak: The Dholak, a hand drum with two heads, is a cherished folk percussion instrument in northern India. It can be played seated, standing, or with one knee. With a barrel shape and basic skin coverings, it plays a vital role in regional music and dance.
- Kanjira (Khanjari): Originating from South India, the Kanjira is a frame drum characterized by a circular wooden frame holding a stretched skin, usually from an iguana. It commonly features three or four slots on the side for attaching bell-metal jingle disks via metal crossbars.
- Mridangam: The Mridangam, a barrel-shaped drum with an elongated form, is predominantly used in South India.
- Pakhavaj: The Pakhavaj, a drum with a barrel-shaped structure, features two heads, each coated with a tuning paste known as siyahi. Though the historical origins of the Pakhavaj are unclear it played a crucial role as a precursor to both the Hindustani Tabla drums and the Mridangam in Carnatic music.
- Tabla: Tabla, a dual-drum instrument, comprises the Bayan and Dayan. The Bayan, larger and played on the right, is often metal or pottery with off-center siyahi for pitch adjustment. Dayan, smaller and on the left, typically rosewood, yields higher tones. Both drums utilize tuning paste for varied tonality.
Clockwise from top left: Kanjira or Khanjari; Dholak; Pakhavaj; Mridangam maestro TS Nandakumar
In drumming, vibrations originate from striking a membrane stretched over a shallow frame. This can be done by hand percussion or drumsticks, typically favouring circular membranes. Lord Rayleigh’s mathematical analysis focuses on perfectly flexible, infinitely thin circular membranes. However, practical drums exhibit variations. Tension isn’t the sole restoring force; vibrations compress and expand the cavity’s air, altering drumhead frequencies. Additionally, drums are struck at points between the centre and edge, not just at the centre, adding complexity beyond theoretical frameworks.
Although similar in some aspects, the Mridangam and Tabla exhibit distinct acoustic characteristics. Playing the Mridangam primarily involves using the flat of the hand, while Tabla players typically use their fingertips. The Mridangam features a hollow jackwood shell resembling a barrel shape, with varying diameters along its length. Its right head consists of three layers of skin, including outer rings of goat’s skin and a middle disc of cow’s skin, tensioned after soaking in water. Leather braces, interlaced and looped through holes in the skin, adjust tension. The left head comprises buffalo and goat skin layers, with wood pieces inserted for further tension adjustment. Resin, boiled rice, and fine dust paste applied to the right skinhead’s centre produce ‘chapn’ and ‘meetu’ sounds. The left head is prepared with a flour-water mixture for the ‘panchama’ sound. The primary note, ‘sa’, is generated by striking the right hand’s fingers on either the edge or centre.
Indian drums possess a unique characteristic wherein they are tensioned over a central area, resulting in the generation of harmonic partials. The concept of gradually increasing the weight or thickness of the drumhead from the rim to the centre has been theoretically established to produce harmonic overtones. This empirical knowledge has been applied by drum makers in India for an extended period. Additionally, the cylindrical chamber’s presence significantly enhances both the volume and tone quality. However, even a minor crack in the wooden shell’s walls can lead to a loss of tonal quality. Mastering the art of drumming is intricate and demands a specific technique, requiring extensive practice utilizing the hands, fingertips, and wrists.
One distinctive feature of harmonic drums is their ease of excitation, allowing for the observation of various vibration modes. The fundamental mode, lacking internal nodal lines, is best initiated by firmly striking the centre with the flat palm and quickly removing it, producing a deep, overtone-free hum. The second mode, characterized by a single nodal diameter, is excited by smartly striking the membrane’s edge with the palm while allowing the little finger to rest along a diameter, facilitating rapid recoil. To isolate the third mode, gently touch the membrane with fingers at two adjacent points near the edge of the central load, then strike the drum with a finger at a point 90 degrees away, producing a clear, resonant tone. This creates two parallel nodal lines across the drum, evident from sand patterns. The fourth mode can be initiated by lightly touching the edge of the loaded area at three points and then striking the drum at a point 90 degrees away from the middle of the three touched points, resulting in three parallel nodal lines. The fifth mode can be excited by touching the loaded area’s edge at four points and striking the drum at a point on the marginal leather ring some distance away.
The harmonic relationship among the five drum tones becomes evident through sequential excitation. The fundamental tone occurs when the drumhead vibrates as a whole. Successive harmonics correspond to divisions of the drumhead into equal parts with nodal lines. This analogy to a vibrating stretched string is striking, as both systems exhibit harmonic modes. The drum’s resonant behaviour mirrors that of the string, highlighting the fundamental principles of vibration and harmonics across different physical systems.
*The writer is Associate Professor, Department of Physics, University of Lucknow.
