# Rockbox

• Status Closed
• Percent Complete
100%
• Category Music playback
• Assigned To No-one
• Operating System All players
• Severity Low
• Priority Very Low
• Reported Version
• Due in Version Undecided
• Due Date Undecided
• Private
Attached to Project: Rockbox
Opened by brucebertrand - 2004-06-17
Last edited by RaeNye - 2006-09-20

## FS#2231 - Pitch adjustment in musical terms (for practicing musicians)

For musicians who use the pitch adjustment feature for
practice (mostly with Jazz playalong’s), adjusting the
pitch with the current method is not very useful.

A nice option would be to adjust the pitch by semitones
(or half steps).

To raise pitch in equally tempered half steps, use the
following equation:

F = (2^(1/(12/N))) * B

Where:
F = end frequency
B = starting frequency
N = # of half steps displaced (absolute value)

To lower pitch, divide, rather than multiply, by B

Is accurate enough math possible (and efficient) with
the archos (recorder)?

If not, you can use: F = B * 1.06^N

This method is only relatively accurate to about a
perfect 5th (7 half steps), which is OK. A perfect 5th
up plus a perfect 5th down gives you more than an
octave, and thus, covers all keys.

Also usefull, for those who would be thinking in
musical terms, is displaying the adjustment not by the
number of half steps (+4 , -2 , etc…) , but by
interval (M3 up, m2 down, etc…)

For reference, if whoever might implement this doesn’t
have a musical background, a interval list follows:

1 = m2 (minor 2nd)
2 = M2 (Major 2nd)
3 = m3
4 = M3
5 = P4 (Perfect 4th)
6 = TT (Tritone)
7 = P5
8 = m6
9 = M6
10 = m7
11 = M7
12 = 8va (Octave)

Too bad there’s not enough processing power to do this
without affecting the tempo.

TIA

Closed by  zagor
2006-11-10 19:07
Reason for closing:  Fixed
Additional comments about closing:   Warning: Undefined array key "typography" in /home/rockbox/flyspray/plugins/dokuwiki/inc/parserutils.php on line 371 Warning: Undefined array key "camelcase" in /home/rockbox/flyspray/plugins/dokuwiki/inc/parserutils.php on line 407

Closing all feature requests.

I have added  FS#6145  as a related task. It has a patch for this, but affects the tempo as well as the pitch.

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