Örjan Hansson's Website: ohw.se

3. Tuner

The tuning scheme in the previous section should be interpreted in the following way: The numbers for the blow and draw notes in the different channels (holes) tell how many cent the note should differ from the corresponding note in 12-tone equal temperament (12TET). That is, how much they should differ from those on, for example, a (well-tuned) piano.

There are (hardware) instrument tuners with a moving needle that display the deviation in cent from 12TET when a note is played into its microphone. Thus, for a well-tuned harp, sounding a 1B (the blow note in hole 1) should result in no deviation, 2B should give a negative deviation of 14 cent, 3B shold give a positive 2 cent deviation, and so on.

3.1 Software tuner

I use a software tuner called Chromatia Tuner (version 3.1) that I highly recommend. The tuner is shareware and can be obtained from the maker FMJ-Soft. I have installed it on my laptop computer and use it with a Shure SM57 microphone connected to an SB Audigy 2NX external soundcard.

In addition to working as an ordinary (hardware) tuner, Chromatia can also apply octave stretching and it is easy to change the master tuning. However, it has an additional special feature that I find very conveniant: It is not restricted to 12TET but can easily be used with other tuning schemes. The tuner will then show deviations (in cent) from those other tuning schemes.

There are quite a number of alternative tuning schemes already included with the program. But one can also add custom ones in the form of text files that follow a simple format called Scala [Op de Coul, 2001]. I use Chromatia with the following Scala file which corresponds to the tuning scheme in the previous section.

! ji_hca19.scl by Orjan Hansson, 2004-07-17, 2006-12-27
! Lines starting with an exclamation mark are
! treated as comments in Scala files.
! The following is a short description of the scale:
19 limit JI for hca (2nd and 3rd pos)
!
! Some comments left out.
! The following number tells how many notes
! there are in the scale:
 7
!
! Here follows the definitions of the notes in
! the scale. (Only numbers are read, the rest is
! treated as a comment.)
!
 9/8 Major whole tone
 5/4 Major third
 171/128 Perfect fourth increased with 3 cent as a
! compromise between 2nd and 3rd pos
 3/2 Perfect fifth
 27/16 Major sixth increased with 22 cent
 15/8 Major seventh
 2/1 Octave

Chromatia will load this file upon start if it exists in the same directory as the executable. Then the deviations shown by the tuner will correspond to deviations with respect to this tuning scheme.

Here are some Scala files that I have written for harmonica tuning:

• JI for hca (1st pos)
• JI for hca (2nd pos)
• JI for hca (3rd pos)
• 19-limit JI for hca (2nd and 3rd pos) (the one I currently use)
• JI for hca (2nd and 3rd pos) (an alternative to the above)
• JI for nat minor hca (2nd pos)

3.2 Chromatia settings

I use Chromatia with the following settings (Options/Tuning):

Scale root key

This should be set to the key of the harmonica.

Octave stretch

I use 2 cent/octave.

Master tuning

Usually, harmonicas are tuned a little sharp, for example to A4 = 443 Hz (12 cent above 440 Hz). When using Chromatia with tuning schemes other than 12TET, it is very important to set the master tuning to the desired frequency of the scale root key. For a C major diatonic harmonica, one should set C4 to 263 Hz (9 semitones of 12TET below A4 = 443 Hz).

For a natural minor harp played in 2nd position one should set the scale root key and master tuning to that of the 2nd position root note (if the above Scala file is used).