Espozo wrote:I had never heard of multiple sound samples being used for different notes of one instrument.
It's usually called "multisample", but it might have other names. It's actually the reason why XM and IT formats have a separate collection of "samples" and "instruments", i.e. the instruments reference many samples. Interestingly, even Famitracker has this feature, where the instrument maps DPCM samples to keys.
There's another dimension of this called "multitimbral" where you play multiple samples per note, e.g. you could blend between a "soft" and "hard" version of an instrument depending on how fast you press the key, which could have more expressive variation of the sound than just changing the volume, like you would without this feature.
Espozo wrote:do you have a good comparison between a synth that is using one sample and changing the pitch vs one that isn't?
Piano samples are mentioned often because the disparity between a real piano and a sample pitch up or down gets very strong rather quickly, and pianos have a very large range for an instrument so there is something real to compare against, too. Pianos also have a separate set of strings and hammer for each note, designed and adjusted to give a good tone across the whole range (e.g. thicker/fewer strings on the bass, softer hammers on the treble), so it's a bit removed from the ideal thing that a samplerate change could replicate where each successive pitch should be identical components just scaled smaller.
All samples when pitched lower than their recorded frequency will start to have audibly missing high frequency components (i.e. sound too "dull") and at the same time have their envelopes lengthened (sound too "long" or "slow"). Conversely, when pitched higher, there is proportionately too strong a high frequency component compared to a natural instrument's pitch change, aliasing problems tend to build up in the high frequencies, and the envelopes become shortened too.
For a piano sample taken too far you get a very tinny short tink for high notes, and a very dull booooong for low notes. Everything is out of proportion. In reality the low pitches on a piano do have a longer envelope, but not THAT long, and high pitches do have a shorter one (but not THAT short), so you'll actually see this accounted for in synthesized approaches. Yamaha's FM synthesizers have "keyboard rate scaling" to adjust the speed of envelopes across the range of the keyboard, and "keyboard level scaling" to similarly adjust the timbral effect across the range (dampening high frequencies for high notes to keep them from sounding unnaturally harsh).
I can't point to a good example of how it sounds bad, because usually composers just avoid playing that piano outside its range, because it tends to sound
bad. Maybe just find
a random MOD with piano samples, open it up in
OpenMPT or some other tracker and try for yourself how the individual samples sound when play them in different ranges. (This particular MOD has one "bass" piano sample, and one mid-range sample, and avoids going very high. You can easily hear the harsh tone of its higher notes though, and in general how various notes sound too bright or too dull.)
I always thought the
game over screen from Super R-Type had a really fun use of a piano sample. It is used over a wide range, but outside a small range it sounds very unlike a piano. At some point it does interesting pitch sweeps in the low range that might as well be a sine wave. It also seems to avoid going very high in pitch, maybe to avoid it standing out too harshly compared to its fairly dull sound in the range it's mostly used.
psycopathicteen wrote:The Neo Geo's YM2610 sound chip was designed to waste space.
It's designed to play sound effects and drums. Wasting space to use those sound effects for music was someone else's goal. ;P They might have considered it putting that space
to good use rather than wastage. The only wasted space is empty.