sfplay3

sfplay3 --  Plays a SoundFont2 (SF2) sample preset, generating a stereo sound with cubic interpolation.

Description

Plays a SoundFont2 (SF2) sample preset, generating a stereo sound with cubic interpolation. These opcodes allow management the sample-structure of SF2 files. In order to understand the usage of these opcodes, the user must have some knowledge of the SF2 format, so a brief description of this format can be found in the SoundFont2 File Format Appendix.

Syntax

ar1, ar2 sfplay3 ivel, inotnum, xamp, xfreq, iprendx [, iflag]

Initialization

ivel -- velocity value

inotnum -- MIDI note number value

iprendx -- preset index

iflag -- flag regarding the behavior of xfreq and inotnum

Performance

xamp -- amplitude correction factor

xfreq -- frequency value or frequency multiplier, depending by iflag. When iflag = 0, xfreq is a multiplier of a the default frequency, assigned by SF2 preset to the inotenum value. When iflag = 1, xfreq is the absolute frequency of the output sound, in Hz. Default is 0.

sfplay3 plays a preset, generating a stereo sound with cubic interpolation. ivel does not directly affect the amplitude of the output, but informs sfplay3 about which sample should be chosen in multi-sample, velocity-split presets.

sfplay3 is a cubic-interpolation version of sfplay. Difference of sound-quality is noticeable specially in bass-frequency-transposed samples. In high-freq-transposed samples the difference is less noticeable, and I suggest to use linear-interpolation versions, because they are faster.

When iflag = 0, inotnum sets the frequency of the output according to the MIDI note number used, and xfreq is used as a multiplier. When iflag = 1, the frequency of the output, is set directly by xfreq. This allows the user to use any kind of micro-tuning based scales. However, this method is designed to work correctly only with presets tuned to the default equal temperament. Attempts to use this method with a preset already having non-standard tunings, or with drum-kit-based presets, could give unexpected results.

Adjustment of the amplitude can be done by varying the xamp argument, which acts as a multiplier.

Notice that both xamp and xfreq can use k-rate as well as a-rate signals. Both arguments must use variables of the same rate, or sfplay3 will not work correctly. iprendx must contain the number of a previously assigned preset, or Csound will crash.

These opcodes only support the sample structure of SF2 files. The modulator structure of the SoundFont2 format is not supported in Csound. Any modulation or processing to the sample data is left to the Csound user, bypassing all restrictions forced by the SF2 standard.

See Also

sfilist, sfinstr3, sfinstr3m, sfinstr, sfinstrm, sfload, sfpassign, sfplay3m, sfplaym, sfplay, sfplist, sfpreset

Credits

Author: Gabriel Maldonado

Italy

May, 2000 (New in Csound Version 4.07)