Pitch-to-Frequency Calculator

Use this calculator to convert between musical pitch and the frequency of the sound (in both directions).

Pitch-to-Frequency Calculator

by Clint Goss, version 1.01

Documentation

This calculator lets you convert between musical pitches and their corresponding frequencies. It works in both directions (pitch to frequency and frequency to pitch).

The easiest thing to do is to play with the various inputs, in particular the [+] and [-] buttons, and see how the frequency changes. Alternately, any change in the frequency will be reflected back to the pitches on the left side.

Note that error checking on the input is not complete. If you enter an inappropriate entry (such as something other than a number), results can be unpredictable.

For more background information on this calculator, including the folks who contributed to the code base, see the Tools and Calculators Overview page.

Units

Frequency can be scaled to any of these units:

¹Cycles per Earth day, based on a calendar day (also called a "synodic day") - the time from midnight to midnight on two successive days. The duration of a true revolution of the Earth around its axis - a "sideric day" - is about 4 minutes shorter than the average calender day. Also note that because of leap days, a day will occasionally have 86,401 seconds.

²Cycles per first-order Schumann Resonance interval. The default value is 7.55Hz, the average reported in [Ondraskova 2009], page 351 as the average for the period June 2008 to May 2009. However, you can set the value to any frequency you wish. See Schumann Resonance below. (You can also use this field to set any base for the frequency value in Hertz.)

Schumann Resonance

Low-frequency electromagnetic waves that are triggered by worldwide lightning activity and travel in the Earth's ionospheric cavity - the space between the Earth's surface and the ionosphere. There are typically about 2,000 active thunderstorms at any given time, and the lightning strikes from these storms set up a series of continuous electromagnetic waves. The frequency of these waves is based on the circumference of the Earth and atmospheric conditions ([Polk 1983] and [Nickolaenko 2002]).

The frequency of the waves depends on the number of reflections off the Earth's surface and the base of the ionosphere:

The different modes of skipping produce different discrete frequencies, termed the first order Schumann Resonance, second order Schumann resonance, etc ...

The exact frequency of each Shumann resonance varies with the height of the Earth's ionosphere, the location of the measuring station, and seasonal variations, and the amount of solar flare activity ([McGlade 2004]). There are many stations that measure and record these frequencies. One station that reports near-live results is the IK1QFK VLF Monitoring Station in Cumiana, Northwestern Italy.

These graphs from [Fullekrug 2010]  show measured frequencies at two stations: the PKD station in Parkfield, California and the Arrival Heights station in Artarctica. Note that the first-order Schumann Frequency varies locally by about 0.3 Hz, changes seasonally, and also changes gradually in response to the Sun's solar flare activity.

Figures 1 and 2 from [Fullekrug 2010]  showing first-order Schumann Resonance measurements at Parkfield, CA and Arrival Heights, Artarctica

Figures 1 and 2 below, which show the daily averages of the first Earth-ionosphere cavity resonance frequency measured at the PKD station in Parkfield and at the Arrival Heights station in Artarctica, exhibit a typical natural variability < 0.3 Hz. This variability results from the solar short wave radiation, which ionises the atmosphere at 90-100 km height.

Historically, a value of 7.83 Hz was used for the frequency of the first-order Schumann resonance, but the frequency has been decreasing from 2002 through 2009, as shown on these charts from [Ondraskova 2009]:

Figures 2 and 3 from [Ondraskova 2009]

The top chart shows the daily average (mean) values of the fundamental (first-order) Schumann resonance frequency from October 2001 through May 2009. The lower chart shows the monthly and yearly mean values of the fundamental Schumann resonance frequency in two frequency bands. The yearly mean for June 2002 through May 2003 is 7.85 Hz. The yearly mean for June 2008 through May 2009 is 7.55 Hz.

Based of this, I use 7.55 Hertz as a default value in the calculator above. However, you are free to enter any value you wish.

If you find any problems or suggestions regarding this page, please contact me.

Revision History

Version 1.01 - December 15, 2010

• Initial release, based on code from the Basic NAF tool.