Drone Instrument/Sruti Box: New Version

Posted 14 November 2010, 15:47

Latest release: version 2.8, 14-Nov-2010 (see release notes below).

In 2005, I made a drone instrument. It’s been in the back of my mind for a long time to revise it, and I have finally done so. Here is a substantially rewritten version, one that has better sound quality and more sonic possibilities. Hopefully it is also easier to use.

You are welcome to use this instrument in your own music. If you do, I’d love to know about it and hear the recordings (if any).

Before I explain how to install and use it, I’d first like to thank AndrĂ©s Cabrera and his collaborators for QuteCsound, the excellent new authoring and performance front-end for Csound. I made this instrument in QuteCsound, and QuteCsound is required to play it. Andres and Joachim Heintz generously helped me to get this right, fixing bugs and offering useful suggestions.

Thanks also to David First, from whose article The Music of the Sphere: An Investigation into Asymptotic Harmonics, Brainwave Entrainment and the Earth as a Giant Bell comes the Asymptotic Sawtooth Wave, which is a new waveform choice in this version of the instrument.

For background information, please see the original article for background information on the drone box, much of which still applies.

Screenshot - click for full size
Click for a full-size image.


  1. Download Csound5 from here – here is the link to the Windows installer. There are Mac and Linux versions as well, and they should all work, but I have not used them myself.
  2. Run the Csound5 installer you just downloaded.
  3. Download the Sruti/Drone Box and save it somewhere that you’ll remember, such as the desktop.


  1. Run QuteCsound: on Windows, go to the Csound menu from the Start button and then click “qutecsound”).
  2. Open the Sruti/Drone Box in QuteCsound: click the Open button, find the Sruti/Drone Box file you downloaded above and double-click it (the filename is SuiteDrone-2.8.csd).
  3. If you don’t see something that looks like the image above, click the Widgets button in QuteCsound.
  4. When you see the Sruti/Drone Box, click the Start button.



Recording the Output


QuteCsound has a preset features that allows you to save your settings, including multiple variations of setting. This is very handy if you come up with different tunings and effects configurations: just save them, each with a different name, and you can recall them at any time (without having to do something tedious like writing them all down and painstakingly reentering them).

If you right-click on the Sruti/Drone Box, you will see three items at the end of the menu called “Store Preset”, “Recall Preset” and “New Preset”. Use Store to save your current settings, either to an existing preset name or to a new one; use Recall to use a previously saved preset; use New to make a new one.

I have established a few presets to give you some idea of the possibilities.

Tuning Ratios

I use ratios because I prefer the sound of intervals tuned in just intonation, and ratios are the simplest and most precise notation for describing them.

Here are some commonly used ratios for a diatonic scale in just intonation (the note names are for reference only):

1/1 9/8 5/4 4/3 3/2 5/3 15/8 2/1

There are many other possible ratios, even for a diatonic scale. See Tuning Systems and follow the links if you would like to know more.

For an Indian classical music perspective on tuning and just intonation, see Shrutis in Hindustani Music.

Sample Drones

Sruti/Drone Box samples by mysterybear

Updates & Release Notes

Download Links


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  1. — Paul Muller    27 September 2010, 02:01    #

  2. Dave Seidel    27 September 2010, 02:25    #

  3. — Paul Muller    27 September 2010, 17:29    #

  4. Dave Seidel    27 September 2010, 17:35    #

  5. — Paul Muller    27 September 2010, 20:19    #

  6.    9 October 2010, 17:45    #

  7. sam    19 October 2010, 03:12    #

  8. Dave Seidel    23 October 2010, 16:24    #

  9. Brad    15 January 2011, 18:36    #

  10. Dave Seidel    15 January 2011, 18:43    #

  11. — Sean    30 January 2013, 01:40    #

  12. kymatika    28 July 2013, 20:35    #

  13. Dave    29 July 2013, 13:38    #