101 lines
5.1 KiB
Markdown
101 lines
5.1 KiB
Markdown
# wavetables
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wavetable chips, in context of Furnace, are sound generators that operate on extremely short, looping sample streams. by extremely short, usually no more than 256 samples.
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this amount of space is nowhere near enough to store an actual sampled sound, but it allows certain amount of freedom to define a waveform shape.
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each chip has its own maximum size, shown in the following table. if a larger wave is defined for these chips, it will be scaled to fit within the constraints of the chips.
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some of these chips force a phase reset when changing waveforms, which can cause clicking and popping sounds. this also means they don't work very well with the [wavetable synthesizer](../4-instrument/wavesynth.md). these systems are marked in the "notes" column.
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system | width | height | notes
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Bubble System | 32 | 16 |
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Game Boy | 32 | 16 | phase reset on waveform change
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SM8521 | 32 | 16 |
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Namco WSG | 32 | 16 | RAM only
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WonderSwan | 32 | 16 |
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Namco 163 | ≤240 | 16 | limits differ depending on channel count
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SNES | ≤256 | 16 |
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PC Engine | 32 | 32 | phase reset on waveform change
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Virtual Boy | 32 | 64 | phase reset on all channels on waveform change
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FDS | 64 | 64 |
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Konami SCC | 32 | 256 |
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Seta X1-010 | 128 | 256 |
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Amiga | ≤256 | 256 |
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you may use up to 32768 wavetables in a module.
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## wavetable editor
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controls across the top line:
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- waveform number: the `-` and `+` buttons step through the list.
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- open: opens a file selector to choose the file to open.
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- save: opens a file selector to choose the file to save to.
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- right-clicking brings up a menu:
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- **save as .dmw...**: saves the selected wavetable in DefleMask format.
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- **save raw...**: saves the selected wavetable as raw data.
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- create sample from wavetable: copies wavetable to a new looped sample.
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- **Steps**: view waveform as discrete blocks.
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- **Lines**: view waveform as a continuous line.
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- **Width**: length of the waveform data. maximum is 256.
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- **Height**: height of the waveform. maximum is 256.
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- `<` / `>`: show/hide waveform utilities (described below).
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waveform display:
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- the waveform is directly editable with the mouse.
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- hovering will display a tooltip with the waveform position and value.
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controls across the bottom line:
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- **Dec**: view text input as decimal.
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- **Hex**: view text input as hexadecimal.
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- `+` / `±`: toggle text input as unsigned/signed. also adjusts waveform display.
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- text input: waveform data as an editable numeric sequence. also called "MML stream".
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## waveform utilities
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these provide different ways of creating or altering a waveform.
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### Shapes
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this creates a waveform by adding together a few predefined basic wave shapes.
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- shape: select shape from sine, triangle, saw, and square.
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- **Duty**: only affects pulse waves, determining their width.
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- **Exponent**: applies an exponent (power) to the waveform (^2, ^3 and so on).
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- **XOR Point**: determines the point where the waveform gets inverted.
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- **Amplitude/Phase**: add together up to 16 instances of the shape.
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- **Amplitude**: height of the shape.
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- **Phase**: position along the shape. for example, 0.250 starts the shape a quarter of the way along.
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### FM
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this creates a waveform using frequency modulation synthesis with up to four operators.
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you can set carrier/modulation levels, frequency multipliers, connections between operators and FM waveforms of these operators.
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in the connection diagram, a checkmark indicates that the row operator is modulated by the column operator. the "Out" column indicates which operators are audible. the default diagram (as shown) sets operators 1, 2, and 3 as modulators in sequence, with operator 4 as the carrier and only output.
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### WaveTools
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these are useful editing tools to fine-tune the waveform:
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- **Scale X**: stretches the waveform to a new length.
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- **interpolation method**: filters the waveform when stretching. choose from none, linear, cosine, and cubic interpolation.
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- **Scale Y**: resizes the waveform to a new height. it will clip at the top and bottom.
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- **Offset X**: slides the the waveform forward or back. it will wrap around.
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- **Offset Y**: slides the waveform up or down. it will clip at the top and bottom.
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- **Smooth**. averages values in the waveform.
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- **Amplify**. changes the volume of the waveform. it will clip at the top and bottom.
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- **Normalize**: stretches waveform to maximum within the wavetable height.
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- **Invert**: flips waveform vertically.
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- **Reverse**: flips waveform horizontally.
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- **Half**: halves the waveform's frequency by stretching its first half to fill the waveform length.
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- **Double**: doubles the waveform's frequency by squashing it to half length then repeating it.
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- **Convert Signed/Unsigned**. worth trying if an imported wave sounds corrupted.
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- **Randomize**: generate a completely random waveform.
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