xfmedit - FM Synthesizer Sound Editor

Introduction

xfmedit is a editor for the Yamaha OPL-3 FM synthesizer. The FM synthesizer uses various oscillators and filters to generate sound. The OPL-3 FM synthesizer provides 18 channels of 2-operator FM sound or 6 channels of 4-operator FM sounds. The synthesizer is capable of generating stero FM tones at 44.1KHz. It uses "operators" which can be considered to be "mini synthesizers" and can be combined in many different ways to simulate musical instrument timbres. The FM synthesizer also has percussion instrument generation capabilities. There are 5 different percussions instruments:

• Bass drum
• Snare drum
• Cymbal
• Tomtoms
• Hihat

For detailed description of the FM synthesizer please refer to the /dev/dmfm0 device programming section. Shown below is the xfmedit editor. This editor provides access to all four operators.

Controls

• Quit - this button quits the application
• Reset - this button resets the FM synthesizer's controls to the default values.
• Load - this button reads a SBI FM sound patch file and sets the various sliders to the values specified by the SBI file. For a detailed description of the SBI patch file, please refer to the /dev/dmfm0 programming section
• Save - this button writes out the current FM synth values in a SBI patch file format. Pressing this button will popup a dialog panel in which you have to type in the name of the SBI file you would like to save the FM parameters to.
• Random - this button randomly sets values to various controls. It is a good way to start with a FM tone and then operate on the sound.
• Play - pressing this button plays the current FM sound based on the values set.

Rhythm Section

This section deals with the percussion control buttons.

• Rhythm - setting this button puts the synthesizer in the percussion mode. Toggling this button off sets the FM synthesizer in the music voice mode.
• Bass - pressing this button plays the Bass drum based on the modulator and carrier operator values.
• Snare - pressing this button plays the snare drum based on the modulator's values.
• Cymbal - pressing this button plays the cymbal based on the carrier's values
• Tomtom - pressing this button plays the tomtom drums based on the modulator's values
• Hihat - pressing this button plays a hihat drum based on the carrier's values.

Effects Section

This section sets global effects such as vibrato and tremolo effects on the FM synthesizer.

• Vibrato - setting this button causes a vibrato effect to be applied to the FM tone.
• Tremolo - setting this button causes a tremolo effect to be applied to the FM tone.
• Depth - setting this button caueses more pronounced Vibrato or Tremolo effect on the FM tone.