Re: [Harp-L] Harmonica math

["Vern Smith" <jevern@xxxxxxx>]

The formula for cents is indeed a function of the pitches or frequencies 
involved.

Let Fo be a fixed pitch or frequency.
Let F1 be a slightly different pitch or frequency.
Set C be the difference in cents

The formula is:   C = 1200 / log(2) * ( log(F1) - log(Fo) )
You can work this formula on a scientific pocket calculator or in Excel.

It is derived from a more basic formula:

F1 = Fo * 2^( C / 1200 )

Which comes from the fact that the halftones differ in ratio as the 12th 
root of 2.

There are large tables that give the pitches of all the musical notes and 
interpolation in cents.

Vern
Visit my harmonica website www.Hands-Free-Chromatic.7p.com

----- Original Message ----- 
From: "David Payne" <dave@xxxxxxxxxxxxxxxxxxxxxx>
To: "Harp L Harp L" <harp-l@xxxxxxxxxx>
Sent: Wednesday, May 28, 2008 8:17 AM
Subject: [Harp-L] Harmonica math


> Anybody have the math for converting Hertz to cents. I know that 
> relationship changes with frequency, but I figure there's a table 
> somewhere, if not, I know math exists, if anybody knows that formula, I'd 
> love to know it. Might not be able to work it out, but I'll try.
>
> Dave
> ______________________________
> Dave Payne Sr.
> Elk River Harmonicas
> www.elkriverharmonicas.com
> _______________________________________________
> Harp-L is sponsored by SPAH, http://www.spah.org
> Harp-L@xxxxxxxxxx
> http://harp-l.org/mailman/listinfo/harp-l