I'm using Windows XP. When playing orgs in OrgMaker, I've found some Audio Performance settings* can cause notes to be slightly out of tune. (See
OrgMaker Notes - Audio Performance settings.) Perhaps the MP3s were recorded on a system experiencing the same thing.
* Control Panel -> Sounds and Audio Devices -> Audio tab, Sound playback section, Advanced button -> Performance tab.
I can see the pitches are out of tune when I measure them with a tuner, but it's hard to tell how much I can really hear they're out of tune by ear. While writing this response, I tried to find or make an example org that sounds out of tune when played with Basic acceleration, but sounds in tune with another acceleration setting or when converted to a MIDI file. But it's hard to pinpoint, so I'm not sure how much of this tuning deviation I can really hear, but I think it may be the cause of some of the orgs we think sound out of tune.
More information:
When I first used OrgMaker to play the Cave Story org files, I noticed notes were dropping out: Some notes sort of made a click sound at the beginning and the rest of the note was silent, or some notes didn't play anything at all. I read a suggestion (on this forum I think) to change the audio acceleration setting on my computer. There are four acceleration settings: None, Basic, Standard, and Full. On my computer, only Basic played all the notes without drop outs, so I left it there.
Later I noticed some orgs seemed out of tune. I looked at the tuning settings in the org file, and they seemed to be normal. But when I used an online tuner to measure the frequencies, I found the notes were a little out of tune with each other. I figured this was a quirk of the org-playing routine, and that was the canonical way they always sound.
At one point, I realized OrgMaker's playback may only sound out of tune on my computer for some reason, and everyone else hears it in tune. I tested the other audio acceleration settings and noticed the other three settings (None, Standard, and Full), although they aren't perfect, are much more in tune.
I tested with a second sound card I have in my computer and measured very close to the same results for all four acceleration settings, suggesting it's not a sound card problem. I guess it's some side-effect of the audio functions OrgMaker uses, but I don't know if it only happens on certain operating systems, or if there's other settings or system file versions that influence it.
Update 2011-12-31: I recently tested changing both the hardware acceleration and the sample rate conversion quality settings. See
OrgMaker Notes - Audio Performance settings.
I used the
Seventh String Online Tuner to measure test pitches OrgMaker was playing. I got the same results with both OrgMaker version 1.3.4 (Japanese) and OrgMaker version 2.0.5x (English patch).
Here are the frequencies I measured, along with the deviations from standard A440 tuning in cents. (100 cents is the distance between two semitones in twelve-tone equal temperament.)
Code:
slightly
OrgMaker more in-tune out-of-tune
pitch frequencies frequencies
======== ============== ===============
C3 260.96 C4 -4 260.02 C4 -11
C#3 278.00 C#4 +5 278.41 C#4 + 8
D3 293.98 D4 +2 293.22 D4 - 3
D#3 310.97 D#4 -1 309.69 D#4 - 8
E3 328.97 E4 -3 328.12 E4 - 8
F3 348.99 F4 -1 348.89 F4 - 2
F#3 370.98 F#4 +5 372.46 F#4 +12
G3 390.96 G3 -5 393.75 G3 + 8
G#3 413.97 G#3 -6 411.38 G#3 -16
A3 439.96 A4 0 437.50 A4 -10
A#3 465.99 A#4 -1 467.16 A#4 + 4
B3 493.96 B4 0 492.19 B4 - 6
C4 521.93 C5 -4 520.05 C5 -11
Notes:
The slightly out-of-tune frequencies occured with Basic hardware acceleration and Best or Improved sample rate conversion quality.
The more in-tune frequences occured with all other Audio Performance settings.
In OrgMaker, middle C is C3, and A3 is approximately 440 Hz.
In most tuners, middle C is C4, and A4 is exactly 440 Hz.
Pitches in other octaves were out of tune the same number of cents. In other words, for each octave higher, multiply the frequencies by 2; for each octave lower, divide the frequencies by 2.