Tanpura & Shruti Box Online
A tanpura and shruti-box drone in any Sa, for singing and instrument practice.
Player
Tuned to Sa = C♯3 · 138.59 Hz Pa–Sa–Sa–Sa
Stopped
Press Space to play or stop. The drone keeps playing while you use other tabs.
Sa (your tonic)
Octave 3 puts Sa between C3 (130.8 Hz) and B3 (246.9 Hz). The low Sa string sounds one octave lower.
Tanpura
String tuning
| String and swara | Frequency (ratio to Sa) | Nearest note |
|---|
Pa, Ma and Ni are tuned in just intonation (3/2, 4/3 and 15/8 above Sa), as a tanpura is tuned by ear, so they differ slightly from the equal-tempered notes of a keyboard.
Shruti box
A steady reed drone (like a harmonium held down) that you can play with or without the tanpura.
Practice session
About the Tanpura & Shruti Box Online
A tanpura (tambura) drone for riyaz, singing practice and for accompanying any instrument. Choose your Sa — any of the 12 notes in three octaves, fine-tuned in cents or typed in hertz — and the tanpura plucks its four strings in the classic order: the first string (Pa, Ma or Ni of the lower octave), the two middle Sa strings and the low Sa (kharaj).
The sound is synthesised in your browser, not played from recordings: each string is a modelled plucked string (the Karplus–Strong algorithm) with a jawari-style bridge buzz and the downward glide of overtones that gives a tanpura its shimmer. Add a shruti box (sur peti) of steady reeds, set the pluck speed and rhythm, and let it play in the background while you practise — or save a recording that loops without a seam.
How to use it
- Pick your Sa: the note (its harmonium name is shown too, e.g. C♯ = Kali 1) and the octave. Fine-tune it in cents, or type the frequency in hertz if your teacher or another instrument gives you one.
- Choose the first string: Pa–Sa–Sa–Sa for most ragas, Ma–Sa–Sa–Sa when the raga leaves out Pa (for example Malkauns), Ni–Sa–Sa–Sa for ragas such as Marwa.
- Press Play (or the Space bar). The sound fades in gently; adjust the volume, the pluck speed and the jawari (buzz) to taste.
- Switch on the shruti box for a continuous reed drone and tick the notes it should hold.
- Set Stop after for a timed session, or Download WAV to practise with your music player when you are offline.
Examples
Pa 103.94 Hz · Sa 138.59 Hz · Sa 138.59 Hz · low Sa 69.30 Hz
Pa is exactly 3/4 of Sa: 1.96 cents above G♯2 on a keyboard.
Pa 155.74 Hz · Sa 207.65 Hz · Sa 207.65 Hz · low Sa 103.83 Hz
First string: Ma–Sa–Sa–Sa
Ma of the lower octave = 2/3 × 138.59 = 92.39 Hz (F♯2 −1.96 cents)
C♯, fine tuning −15 cents
Sa = 137.40 Hz
Common uses
- Daily riyaz: sustaining Sa and Pa, alankars and slow alaap against a steady drone.
- Checking your intonation: when your note matches the drone the sound is smooth; a slow wavering (beats) means you are slightly off.
- Accompanying flute, sitar, violin or veena practice in the Sa of the instrument.
- A drone for teaching a class when no tanpura player is available.
How the tanpura is tuned
The four strings are plucked in order, then the round repeats:
- String 1: Pa of the lower octave (3/4 of Sa), or Ma (2/3) or Ni (15/16) in the other tunings.
- Strings 2 and 3: Sa, the pair (jodi) at the pitch you set.
- String 4: the low Sa (kharaj), one octave below (1/2 of Sa).
The intervals are just ratios — a fifth of 3/2, a fourth of 4/3 and a major seventh of 15/8 — because that is how a tanpura is tuned by ear, without beats against Sa. So Pa is 1.96 cents higher, Ma 1.96 cents lower and Ni 11.73 cents lower than on an equal-tempered keyboard; the table lists each string next to the nearest keyboard note. Sa itself is set in equal temperament from A = 440 Hz plus your fine tuning: Sa = 440 × 2^((n − 69)/12 + cents/1200) Hz, where n is the note number (C♯3 = 49, so Sa = 138.59 Hz).
How the sound is made
Each string is a Karplus–Strong plucked string (K. Karplus and A. Strong, Digital Synthesis of Plucked-String and Drum Timbres, Computer Music Journal, vol. 7, no. 2): a short burst of soft noise circulates in a delay line whose length sets the pitch and loses a little of its high frequencies on every pass, as a real string darkens while it rings. A first-order all-pass filter tunes the loop to a fraction of a sample (D. Jaffe and J. O. Smith, Extensions of the Karplus-Strong Plucked-String Algorithm, in the same issue), so every string is in tune to well under one cent.
The jawari is imitated in two steps: a one-sided “bridge contact” that flattens the string’s swing on one side, which adds the buzz, and a resonance that glides down from about 4.8 kHz to 600 Hz in the three seconds after each pluck — the moving band of overtones you hear when a tanpura note settles. Four rounds of plucks, with small differences in timing and strength, are mixed into a loop of 10 to 40 seconds that repeats without a seam, so the drone never sounds mechanical and keeps time even in a background tab.
The shruti box
A shruti box (sur peti) is a small bellows-driven box of reeds that holds notes continuously. Here each reed is a rich harmonic tone with the nasal emphasis of a free reed around its 4th and 5th harmonics. Every note has two reeds 1.2 cents apart, so they beat slowly like paired reeds, and the “bellows” swell the level by a few per cent about every nine seconds. The notes use the same just ratios as the tanpura: low Sa 1/2, Ma 4/3, Pa 3/2, Ni 15/8 and high Sa 2.
Pluck speed and rhythm
The speed is set in rounds per minute, from 6 (one round every 10 seconds) to 24 (every 2.5 seconds). With Pause after low Sa, strings 1 to 3 are one beat apart and the low Sa rings for two beats before the next round; Even spaces all four plucks equally. Slower speeds give a more spacious drone for alaap, faster ones a denser sound for fast passages.
Limitations
- A synthesised model, not a recording of a real tanpura: it is meant as a steady, in-tune practice drone.
- Phones may pause the sound when the screen locks or you switch to another app, and iPhones and iPads usually do. Keep the page open with “Keep the screen on”, or download the recording and play it in your music player.
- Sa can be set from C2 to B4 and fine-tuned by up to ±50 cents, so from about 63.6 to 508.3 Hz.
- Recordings are 16-bit stereo WAV files (about 11.5 MB per minute at 48 kHz); the browser cannot make MP3s without extra software.
Privacy
Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.
Frequently asked questions
Which Sa should I choose?
The one your teacher gave you, or a note where both your low Pa and your high Sa are comfortable. Teachers often name Sa by harmonium keys — C♯ is “Kali 1”, D is “Safed 2”, G♯ is “Kali 4” — and the note list shows those names.
What do “Kali” and “Safed” mean?
The black (kali) and white (safed) keys of a harmonium, counted from C: Safed 1 = C, Safed 2 = D … Safed 7 = B, and Kali 1 = C♯, Kali 2 = D♯, Kali 3 = F♯, Kali 4 = G♯, Kali 5 = A♯.
Why is the Pa string not exactly the Pa of my keyboard?
The tanpura is tuned in just intonation: Pa is exactly 3/2 of Sa, which is 1.96 cents above the equal-tempered fifth of a keyboard. That is far too little to sound out of tune, but a tuner app will show it.
Does it keep playing in the background?
Yes on computers: switch tabs or windows and the drone continues, because the browser’s audio engine plays the loop, not a timer. On phones it depends on the browser and the system, and iPhones and iPads usually pause web audio when the screen locks — keep the screen on, or play the downloaded WAV.
My harmonium is not at A = 440 Hz. How do I match it?
Play Sa on the harmonium and move the fine-tuning slider until the two sound together without slow beats, or type the frequency a tuner shows for your Sa into the hertz box.
I press Play but hear nothing. What should I check?
Check that Volume and Tanpura level are not at zero and that the tanpura is switched On, then your device volume and the output (speakers or headphones). On an iPhone or iPad also check the Ring/Silent switch or Action button: some iOS versions mute web audio in silent mode. If the browser paused the sound during a call, press Play again.
Is anything recorded or uploaded?
No. The sound is generated in your browser and nothing is sent anywhere; once the page has loaded it works offline. The microphone is never used.