What the Hell is a Shruti Box? An Introduction to the Indian Drone Instrument

Ever watched Indian classical music? If you have, you probably remember a rich, continuous hum-mmming sound that anchors the whole concert. You heard that sound-that's the Shruti Box; or, as known as, the surpeti.

Based on the same principle as a harmonium or pump organ, the Shruti Box is a simple drone instrument. But rather than playing tunes, its job is solely to provide an ever-present drone for singers and soloists.

How It Works: Bellows and Reeds

I love the simple beauty of the design of Shruti Box. It involves one or two bellows to blow air through metal reeds that have been tuned, surrounded by a wooden box.

You use the harmonium by pressing on keys to produce notes one after another, but in this instrument the small flaps or knobs on each individual reed are left open or are pressed down, or not, to allow sound. The air flowing through the bellows continues to produce a droning sound so long as at least one flap is left open.

Try it Yourself: The Digital Shruti Box

Let's get started with some history and playing techniques, but in the meantime why not play along at home? Here's a virtual, interactive Shruti Box Simulator to get you started!

Click the "Start Engine" button, choose a few notes (the traditional drone is Sa and Pa) and hear the resonance when you play the notes using your computer's keyboard or mouse.

The Meaning of "Shruti"

The common translation of this term in English is "the smallest interval of pitch that the human ear can hear".

But in the context of Indian Classical music, it has multiple layers of meanings. It could mean a tonic (note, on which a scale is based) and it could also mean the note that is used for tuning various instruments. It is the fundamental, the starting point of any raag.

Tunings and Registers

The Shruti box is a chromatic scale covering a full octave of notes. Traditional Shruti boxes are typically tuned from C to C or G to G but modern manufacturers build them in scales and octaves to suit different needs.

You will frequently come across the words like "Male" and "Female" Shruti Boxes.

• A Male Shruti Box is tuned one octave lower.
• A Female Shruti Box is tuned one octave higher.

For the casual player the choice between them is just a question of which you prefer and which instruments you are accompanying in a band or group. For vocal support, a male or female Shruti is often used to match the vocal range of the singer.

Basic Styles of Playing

1. The Chordal Drone (Accompaniment)

The most straightforward and popular way of playing is as an accompaniment to a singer or soloist. Gently pump the back bellows with one hand and provide the wind to the instrument. Hold the box with the other and occasionally open or close note flaps to alter the notes.

2. Rhythmic Pumping

Although primarily for drones that last for a long time, the Shruti Box can also be played rhythmically. This can be achieved by using the bellows to 'tap' a beat into the air flow. For example, a player could have the front bellows tapping out the rhythm, while keeping the back bellows in motion.

3. Throat Singing & Dual Instrumentation

Most singers that are capable of an overtone style of throat singing utilize a Shruti Box as their drone. Its sound will support the singer to match their breathing to the instrument.

Many also tend to improvise on other instruments while droning away. Since the Shruti Box is simple enough to play where you can multitask, you may even find yourself watching professionals play the Saxophone or Flute with one hand and pump the Shruti box with the other!

The Craftsmanship Behind the Sound

Although digital simulators (such as the one above) are handy for practice whenever you're out and about, nothing can replace the deep, earthy acoustic resonance of a real, hand-made wooden Shruti Box.

Our craftsmen at Shriji Crafts carefully carve the wood, place the brass reeds and tune each chamber, one by one. The woods naturally resonate and sound boards amplify the drone giving it an unmatched richness and warmth, with no speaker or any other device for that matter coming near it.

To discover the true Acoustic sound of this elegant instrument, browse our selection of hand made Shruti Boxes below.