Shruti Generator: The Complete Guide
A shruti box holds one thing steady: a continuous, uninterrupted tone that a singer or instrumentalist tunes and practices against. This tool recreates that sustained reference electronically — set your Sa, choose which additional notes to layer in, and get a steady, held drone that runs right in your browser, no app or download required.
How does this shruti generator work?
Unlike a plucked-string instrument, a shruti box produces its tone continuously from a set of reeds, closer in character to a harmonium than to a tanpura's decaying strings. This tool mirrors that behavior using the Web Audio API: each selected note is generated as a sustained oscillator tone, layered with a subtly detuned second oscillator for warmth, and passed through a gentle lowpass filter so it holds a steady, mellow tone for as long as it's running, rather than fading and being re-triggered.
How to Use the Shruti Generator
- Set your Sa using the − and + controls to match your voice, instrument, or an accompanying performer.
- Choose your drone notes — Sa alone, Sa with Pa, Sa with Ma, or Sa with Pa and an upper-octave Sa — from the chips below the Sa control.
- Set the volume so the drone sits comfortably behind your own playing or singing.
- Tap "Start Drone" and let it hold steady in the background while you sing, play, or practice intonation.
- Adjust Sa or the note combination at any time — the drone updates the next time you start it, so you can quickly compare different reference setups between takes.
Shruti Generator vs. Tanpura Drone: What's the Difference?
Tunerium's Tanpura Drone plucks four strings in a repeating cycle, closely following how an acoustic tanpura actually works — each string rings out and decays before the cycle comes back around. This Shruti Generator instead holds its selected notes as one continuous, unbroken tone, the way an electronic or reed-based shruti box does. Some practitioners prefer the tanpura's cyclic rhythm as a subtle pulse to sing against; others prefer the shruti box's uninterrupted steadiness. Both are tuned the same way — by ear, against your chosen Sa — so the right choice comes down to which texture you find easier to practice with.
| Tool | Texture | Closest To |
|---|---|---|
| Shruti Generator | Continuous, unbroken tone | An electronic or reed shruti box |
| Tanpura Drone | Cyclic, decaying plucks | An acoustic tanpura |
Common Drone Note Combinations
Which notes to sustain alongside Sa depends on the same raga considerations as a tanpura's second string, plus how much harmonic context you want while practicing:
- Sa only — the simplest and most neutral reference, useful for isolating pitch accuracy on a single tone without any harmonic color to lean on.
- Sa + Pa — the most common general-purpose combination, adding the fifth for a stable harmonic foundation.
- Sa + Ma — used for ragas that favor the fourth degree over the fifth.
- Sa + Pa + Sa (upper) — a fuller reference that adds an upper-octave Sa on top of the fifth, giving more harmonic richness for longer practice sessions.
Beyond Indian Classical Practice
A sustained reference tone is useful well outside Hindustani and Carnatic contexts. Vocalists in any tradition can use a held Sa to check intonation on long tones, instrumentalists can use it to tune by ear without a chromatic tuner, and ear-training exercises across genres often rely on exactly this kind of stable drone to judge intervals against. Setting Sa to a Western pitch, such as C or A, works just as well as setting it for a raga.
Common Shruti Generator Questions
Why does my chosen combination not update while the drone is playing?
Changes to Sa or the note combination take effect the next time you start the drone, rather than live-updating a currently sustained tone. Stop and restart the drone after making a change to hear the new setting.
Why does the tone sound simpler than a real shruti box?
A physical shruti box's reeds produce a naturally rich, slightly imperfect harmonic texture that's difficult to fully reproduce with oscillators. This tool aims for a clean, steady, accurately pitched reference for practice rather than an exact acoustic reproduction.
Frequently Asked Questions
Is this online shruti generator free to use?
Yes. This shruti generator is completely free, runs in your browser, and does not require an account, download, or app install.
What is a shruti box?
A shruti box is a small reed instrument that produces a continuous, sustained drone, traditionally used to give a singer or instrumentalist a steady tonic reference during practice or performance. This tool recreates that continuous drone electronically.
What is the difference between the Shruti Generator and the Tanpura Drone?
The Tanpura Drone plucks four strings in a repeating cycle, similar to an acoustic tanpura. The Shruti Generator instead produces a continuous, sustained tone, similar to a harmonium-style shruti box, which some practitioners prefer for its steadier, uninterrupted reference pitch.
Can I use the shruti generator for instruments other than voice?
Yes. A sustained reference tone is useful for tuning and intonation practice on any instrument, not only for singers, and works equally well for Western scale and interval practice as it does for Hindustani or Carnatic riyaz.
This tool only produces sound — it does not use your microphone, and no audio is recorded, stored, or sent to a server.