SoundFonts

With soundfonts it's very easy to turn your computer in synthesizer. A sound font encodes the timbre of the instrument with samples. There are many free soundfonts with good level of quality.

Midi

We can read soundfonts that are encoded in sf2 format. The function sfMsg can turn sound font file in midi instrument:

> let sf = Sf "rhodes.sf2" 0 0
> vdac $ midi $ sfMsg sf 0.5

We play the file "rhodes.sf2" at the bank 0 with program 0. The sound font can contain many instruments. They are identified with the pair of integers: bank and program number. The second argument of the function sfMsg is sustain value of the instrument in seconds.

The funciton sfMsg reads the samples with linear interpolation. We can improve the quality with cubic interpolation if we use the function sfMsg3.

Non-midi

We are not constrained to midi-frequencies. We can read samples at any frequency with function sfCps:

> let sf = Sf "rhodes.sf2" 0 0
> dac $ sfCps sf 0 0.5 440

The arguments are:

• a soundfont preset.

• sustain.

• the amplitude (it ranges in the iterval [0, 1])

• the frequency in Hz.

We can find a lot of soundfonts in the net. Some links to start:

• Hammer sound

• Rhodes

• And many more

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