If someone spots any bugs, mistakes or have other suggestions regarding it, just shout here.
- Noisy V1.0
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Not sure if looped noise is the best term though? I've also seen the term periodic noise. If I understand it correctly, looped noise means that the random wave pattern is shorter or loops faster which makes it more tonal in most pitch settings (pitch $0F doesn't seem to sound any different with the flag set or cleared). Neither terms looped or periodic makes sense to me, the period of a wave is always looping right?
So... the lowest frequency $F is too low to be a pitch, maybe ~2Hz when it's in periodic mode, but it's more like 0.006Hz when it's not. A fast loop repeating twice a second vs. one that's minutes long, too long to notice the looping. Around about $C the periodic mode starts turning into a musical pitch where instead of a repeating noise you just hear a tone.
You should be able to hear a difference in all of them, but not all of them become a pitch.
The actual mode is kind of a short circuit of the LFSR that generates the noise, moving the tap to send the feetback into the LFSR more frequently. The shorter sequence that comes out changes depending on what state it was in when you turned on the periodic noise mode, so the pitched sound changes in character if you turn periodic mode on and off.
So as for terminology, I think "periodic" or "looped" are both fine, though if you want to get more precise maybe it's a "short period" or "short loop" mode? The idea is just that the period/loop becomes pretty noticeable in this mode. Sort of funnily, the length of the period of $0F in periodic mode is similar to the length of $01's period in non-periodic mode (but running at a much lower frequency). The range of rates is wide enough that it overlaps in this respect.
Previous things I've said:
3d graph of first 3 harmonics being random
A cold boot can get a very specific waveform from the period-93 mode that's musically useful
That said, the ×31 harmonic does mean that the very low rates actually become useful in tonal noise mode; the slowest rate there does repeat at 5Hz but it also has a conspicuously audible tone at 147Hz.
I think "short period" describes it the best, but on the other hand "looped" take the least screen space, so I guess it's fine like it is.
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-tiny bell/triangle (the instrument, not the waveform) approximations and
-error signals / "quirky machine sounds".
Sivak used the "error buzz" effect for the logo screen.
What else do you use it for?
I presume it would have some musical relevance if you detuned all other channels to match it, but then again you're confined to it 1)not being chromatic, 2)being a bit random in timbre as described.
The Curse of Possum Hollow uses it for a couple bosses (see attachments).
It's more useful on Game Boy where I can coax decently tuned C, D, F, and G# notes out of it.
It's very good for a "triangle" type sound (percussion instrument, not waveform), like in Solstice.
Often I like 1 frame of periodic noise at the start of an otherwise non-periodic noise instrument. It's good for a "metallic" chip at the start of the sound; sometimes that's good for suggesting something like a cymbal. Sometimes this is just useful for making a different sound that pokes through the rest of the noise, suggesting an extra voice of percussion that can play in its own independent rhythm.
The opposite, 1 frame of noise followed by periodic can be nice just to put an edge on the attack of the triangle type percussion too; not really trying to simulate its realistic sound, but still a useful way to give its attack some defined character.
Tepples mentioned an instrument that alternates between periodic and non every frame, which creates kind of a "fluttery" noise sound; I find this can be really good for sustained cymbal instruments, like a cymbal roll.
Shiru's LAN Master game uses periodic noise constantly for buzzing/beeping noises in the background music. Mega Man 2's Quick Man stage makes similar prominent use of it.
Sometimes people have tried to use the pitches of the noise unit to make melodies. Sivak's jingle was mentioned. I think B00daW did a few little tunes like this but I can't find them right now. Did tepples use it like this for a NIN cover? (Memory hazy.) This is kind of a problem if you want to support both NTSC and PAL, since they have different pitches. (Similar problem to DPCM.)
Anyhow, it's just another sound that you can use. If you try it out and remember the sound, maybe you'll occasionally think of places it might fit. Also, depending whether or not you care about the early Famicom that didn't have it, you may want to test everything with periodic noise disabled just to make sure it still sounds OK without it.
On the Game Boy, not the NES. The pitches of Game Boy looped noise are exactly those of "Wish" from Broken.rainwarrior wrote:Sometimes people have tried to use the pitches of the noise unit to make melodies. Sivak's jingle was mentioned. I think B00daW did a few little tunes like this but I can't find them right now. Did tepples use it like this for a NIN cover? (Memory hazy.)
Sort of related, I once wrote a short piece of music around the NTSC DPCM frequencies and retuned everything else to match it:
The equivalent is possible for noise, to some extent, but even with the DPCM scale I thought found it too restricting. It was fun to write that one little tune, but I doubt I'll ever try to write more music with that technique. (Sometimes harsh limitations can stimulate interesting ideas, but I'm tapped out for that one.)
It doesn't help that the frequencies on an NTSC deck (in period 93 mode) are ~45cents out of tune with A440, while the 31st harmonic is in tune with A440.rainwarrior wrote:The equivalent is possible for noise, to some extent, but even with the DPCM scale I thought found it too restricting. It was fun to write that one little tune, but I doubt I'll ever try to write more music with that technique. (Sometimes harsh limitations can stimulate interesting ideas, but I'm tapped out for that one.)
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div 93freq 12TETA440 3freq 12TETA440 4 4811.2 D-8+41.0 /149147.7 ultrasonic 8 2405.6 D-7+41.0 / 74573.9 ultrasonic 16 1202.8 D-6+41.0 / 37286.9 ultrasonic 32 601.4 D-5+41.0 / 18643.5 ultrasonic 64 300.7 D-4+41.0 / 9321.7 D-9-14.0 96 200.5 G-3+39.0 / 6214.5 G-8-15.9 128 150.4 D-3+41.0 / 4660.9 D-8-14.0 160 120.3 B-2-45.3 / 3728.7 A#7-0.3 202 95.3 G-2-48.9 / 2953.4 F#7-3.8 254 75.8 D#2-45.4 / 2348.8 D-7-0.4 380 50.6 G#1-42.8 / 1570.0 G-6+2.2 508 37.9 D#1-45.4 / 1174.4 D-6-0.4 762 25.3 G#0-47.4 / 782.9 G-5-2.3 1016 18.9 subsonic / 587.2 D-5-0.4 2034 9.5 subsonic / 293.3 D-4-2.1 4068 4.7 subsonic / 146.7 D-3-2.1
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div 93freq 12TETA440 3freq 12TETA440 4 4469.4 C#8+13.4 /138550.6 ultrasonic 8 2234.7 C#7+13.4 / 69275.3 ultrasonic 14 1277.0 D#6+44.6 / 39585.9 ultrasonic 30 595.9 D-5+25.1 / 18473.4 ultrasonic 60 298.0 D-4+25.1 / 9236.7 D-9-29.8 88 203.2 G#3-37.9 / 6297.8 G-8+7.1 118 151.5 D#3-45.8 / 4696.6 D-8-0.7 148 120.8 B-2-37.9 / 3744.6 A#7+7.1 188 95.1 F#2+47.9 / 2947.9 F#7-7.1 236 75.8 D#2-45.8 / 2348.3 D-7-0.7 354 50.5 G#1-47.7 / 1565.5 G-6-2.7 472 37.9 D#1-45.8 / 1174.2 D-6-0.7 708 25.3 G#0-47.7 / 782.8 G-5-2.7 944 18.9 subsonic / 587.1 D-5-0.7 1890 9.5 subsonic / 293.2 D-4-2.6 3778 4.7 subsonic / 146.7 D-3-1.7
Wait, to me that sounds helpful?lidnariq wrote:It doesn't help that the frequencies on an NTSC deck (in period 93 mode) are ~45cents out of tune with A440
Like the DPCM frequencies are all consistently out of tune by a factor of 17/16 because of that off-by-one error in its loop implementation. I shifted the tuning tables in that NSF to compensate.
If the noise frequencies are a fairly consistent deviation from A440 then that in itself is helpful, because it can be compensated by tuning to A440 + 45 cents instead of A440.