# 5.10 OpulenZ OpulenZ is an emulation of the Yamaha YM3812, a.k.a. OPL2, FM synth chip which was used i sound cards around 1990 - the Adlib and Sound Blasters. It generates sound through frequency modulation or adding 2 oscillators. ![OpulenZ](https://2299305010-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LRtsae7H2l0Wn3A4biK%2F-LuiQ0dscJLCeS2qRZ3L%2F-LuiQDfV_WQVgzeqeNYY%2Fimage.png?alt=media\&token=d3b44e60-7874-4c3f-9cc7-052fac2362ee) ## 5.10.1 Operators The two oscillators are called operators. In FM mode (bottom left), operator 1 modulates operator 2. Otherwise both operators are routed to the output. ## 5.10.2 Controls For each operator, the controls are: * **ATT, DEC, SUS, REL:** an ADSR envelope * **KSR:** keyboard scaling rate. When KSR is on, envelopes get faster when the pitch rises. * **PERC:** percussive envelope. Makes the envelope go straight to release ignoring held keys. * **TREM:** applies tremolo (slight amplitude modulation) to the operator * **VIB:** applies vibrato (slight pitch modulation) to the operator * **FEEDBACK:** only for operator 1 - feeds a portion of the operator's output back into ir * **LVL:** the output level of the operator * **SCALE:** determines the scaling applied to the output level when the pitch rises * **MUL:** the frequency multiplier for the operator. 1 stands for the standard pitch played on the keyboard, 0 is one octave below. * **WAVEFORM:** selection from 4 waveforms: sine, half sine, absolute sine and quarter sine. NB: a DC removal plugin might be a good idea when routing waveforms other than sine to the output. ### 5.10.2.1 Global Controls * **FM:** when this is on, frequency modulation is used. Otherwise the operators are mixed together. * **DEPTH, TREM and VIBR:** these select deeper tremolo and vibrato. Applies to both operators. ## 5.10.3 Useful Resources Getting started with FM: Programming the AdLib/Sound Blaster FM Music Chips: (some of the controls are presented inverted in LMMS, to fit better with other symbols)