DavOrgan harmonics aren't working as expected

[tim-janik]

Migrated from: https://bugzilla.gnome.org/show_bug.cgi?id=353456

Stefan Westerfeld:
Within a musical context, there is the fundamental frequency, and harmonics, where higher harmonics correspond to higher frequencies. There is a wikipedia entry with details:

http://en.wikipedia.org/wiki/Harmonics

Thus, I'd expect that the harmonics properties reflect this idea: higher harmonic -> higher frequency. However, by trying out how using 16th, 8th and so on sounds, it seems that higher harmonics correspond to lower frequencies in the DavOrgan module, i.e. that 16th corresponds to the lowest frequency, and 2nd corresponds to the highest frequency.

That seems strange to me. The behaviour of CVS HEAD and 0.6.6 as packaged by debian/unstable is the same here, so its not a recently introduced problem.

Tim Janik:
more details on this bug are provided on the mailing list:
http://mail.gnome.org/archives/beast/2006-December/msg00015.html

Hanno Behrens:
As I mentioned in the beast mailinglist, this is a misleading naming, not a real bug.

If you build organs the pipes are named after their length. An eight feet (8') long pipe is the normal length and therefor the base frequency. A 16' pipe is an octave deeper, a 4' an octave higher than that and so on. 2' therefor two octaves, 1' three octaves.

When you review my "How organs work" mailing on the beast mailing list you can find which length are corresponding to which frequency.

The 1/3th for example correspondent to quintes, the 1/5th to terz means for the multiple of the 3rd harmonic or the 5th harmonic and so on for 7,9,11,13...

So, what does this mean for the DavOrgan module? The naming as "harmonic" is completely wrong. Its the length of the pipes. Simply that is. And this naming is (for organ pipes) shure better than harmonics. Why? There are pipe length that do not directly corresponded to a harmonic but to a harmonic of maybe a 16' pipe. Like 5' 1/3: this is the quint of the 16' pipe. If you multiply 5 1/3 by 3 you get - 16! Voilà. Its the third harmonic of one octave deeper than the base-tone.