KORG EFGSJ 2 Opsix Altered FM Synthesizer User Guide
- June 9, 2024
- KORG
Table of Contents
EFGSJ 2 Opsix Altered FM Synthesizer
User Guide
Introduction
Thank you for purchasing the Korg opsix altered FM synthesizer. To help you
get the most out of your new instrument, please read this manual carefully.
About the opsix manuals
The documentation for this product consists of the following:
- Precautions
- Quick Start Guide (what you’re reading)
- Owner’s Manual (PDF download from the Korg website: www.korg.com)
Main Features
- The opsix features an FM sound generator that produces complex harmonics by rapidly modulating the basic waveforms of its oscillators using other oscillators.
- In addition to FM synthesis, the opsix also features various operator modes such as a ring modulator, wavefolder, effect and so on. The six operators can be combined to create a wide variety of sounds.
- You can use the operator mixer (with sliders and knobs) to directly control the parameters of each operator. This is useful for intuitive editing and making dynamic sound changes when you are performing.
- The opsix includes a rich selection of filters including Polysix and MS-20 models, which covers the bases for making sounds like those generated with subtractive synthesis.
- Three high-definition multi-effects are available, and you can select from 30 types for each.
- 500 programs can be called up and saved in an instant.
- Powerful 16-step polyphonic sequencer.
- A spectrum analyzer and an oscilloscope that let you visualize your sound.
About the sound generator of the opsix
The principles of FM sound
generation were discovered and established by Dr. John Chowning at Stanford
University in the 1970s, when he was experimenting with vibrato. FM sound
generation was later packaged into an LSI chip and put into practical use by
Yamaha Corporation. From the beginning of the 1980s, FM tone generation was
used as an internal sound source on the Yamaha DX series, personal computers,
game machines and cellphones.
-
Operator (modulator, carrier)
The FM (Frequency Modulation) sound generator is based on synthesis elements called “operators.” Operators are modulated using simple input waveforms such as sine waves, outputting sounds with complex harmonics. Operators can act as either a modulator or a carrier. The output sound from a modulator feeds into another operator and modifies that operator’s output. Carriers receive the output sound from modulators and output the modulated result as audio. -
Algorithms
In the FM sound generator, the combination of the roles and connections of the operators is called an “algorithm.” Selecting an algorithm is a good starting point for creating sound. The opsix sound generator includes six operators, and 40 preset algorithms are provided. You can use the user algorithm function to create new combinations as well. -
Operator modes
Although the basis of the opsix is the FM sound generator, you can change the operator mode to perform different kinds of modulation besides FM. The combination of ring modulator, filter, wavefolder and effect makes it possible to create new kinds of sounds that surpass the range of typical FM sounds.
The pitch of an oscillator can be modulated up and down rapidly
using the audio signal from the modulator to change the tonal character.
The input from the modulator is multiplied with the oscillator
signal to make rapid changes to the oscillator’s volume, which changes the
tonal character.
This is a filter with a key tracking function. The
signals from the oscillator and modulator are input into the filter.
OPERATOR MODE
This creates an ultra high-speed wah effect. The cutoff frequency is
modulated using the input from the modulator, and the oscillator signal is
used as audio input for the filter.The wave folder circuit generates harmonics
by folding the waveform back after it crosses a fixed threshold. This mode
will mix the modulator and carrier signals together.
In
this mode, the operator functions as an effect like delay, comb filter or
distortion. The signal from the oscillator and the input signal from the
modulator are inputted into the effect.
Block Diagram
Making connections
Connecting the AC adapter
-
Connect the DC plug of the included AC adapter to the DC 12V jack on the rear panel of the opsix.
Be sure to use only the included AC adapter. Using any other AC adapter may cause malfunctions. -
After connecting the DC plug, loop the AC adapter cord onto the Cord Hook. (Fig. 1)
Do not use excessive force when pulling the cord off the hook.
Doing so may damage the plug. -
Connect the plug of the AC adapter to an AC outlet.
Be sure to use an AC outlet of the correct voltage for your AC adapter.
Other connections
Connect the opsix as appropriate for your audio system.
Be sure that the power on all of your devices is turned off before you make
connections. Leaving the power on when you make connections may cause
malfunctions, or damage your speaker system and other components.
OUTPUT L/MONO, R jacks: Connect these TRS jacks to a mixer, audio
interface, monitor system, etc. Adjust the volume level using the VOLUME knob.
Headphone jack: Connect the headphones here. This carries the same signal
as that of OUTPUT L/MONO and R.
DAMPER jack: Connect a Korg DS-1H damper pedal or a PS-1/PS-3 pedal
switch (sold separately) to control the damper function. Pedal polarity is
detected automatically; to allow this, make sure that the pedal is not held
down when connected, or while turning on power.
MIDI IN, OUT connectors: Use these connectors to connect the opsix to an
external MIDI device for exchanging MIDI messages. Make sure that the MIDI
channels are
set appropriately.
USB B port: Connect this to a computer to exchange MIDI messages and
data.
Turning the power on/off
Turning the opsix On
Make sure that both the opsix and any amplification devices such as powered
monitor speakers are turned off, and turn the volume of all devices all the
way down.
- Hold down the rear-panel (power) button. Once the “opsix” logo appears in the display, release the (power) button.
- Turn on any amplification devices such as powered monitor speakers, and then adjust their volume. Adjust the opsix’s volume using the VOLUME knob.
Turning the opsix Off
- Lower the volume of your powered monitors or other amplification devices, and turn them off.
- Hold down the opsix (power) button until the display shows “Shutting down,” and then release the (power) button.
Auto Power-Off
By default, the opsix will automatically turn off after about four hours have
elapsed without use of the front panel, keyboard, or MIDI input. See the
Owner’s Manual (PDF) for details on how to disable this function.
Playing the opsix
Playing a program
-
Turn the PROGRAM knob [6] to select a program.
-
Play the keyboard to check the sound.
-
To confirm that this is the program you want to select, press the YES button [8].
To cancel the selection and return to the previous program, press the NO button [8]. -
To change the tonal range of the keyboard, press the OCTAVE button [7]. This changes the tonal range of the keyboard in one-octave increments.
-
Use the PITCH wheel [17] to change the pitch. The MODULATION wheel [18] modifies whatever parameter is has been assigned to. It is often used to change the cutoff frequency or vibrato depth. You can also change which parameters are controlled by the MODULATION wheel [18].
Using the analyzer
You can show realtime analysis of the synthesizer’s audio output on the
display [5] by pressing the ANALYZER button [9]. This button switches between
a spectrum analyzer, oscilloscope, and the previously displayed page.
Performing with the arpeggiator
-
Press the ARPEGGIATOR button [20]. “Arpeggiator Run=On” will appear in the display.
-
The pattern set in the program will be used when you play the keyboard.
-
Press the ARPEGGIATOR button [20] once more to turn off the arpeggiator.
“Arpeggiator Run=Off” will appear on the display. -
When you hold down the ARPEGGIATOR button [20], “Arpeggiator Run=Latch” will appear in the display and the latch function will be enabled.
The arpeggiator will keep playing, even if you take your hand off the keyboard. Hold down the ARPEGGIATOR button [20] once more to disable the latch function.
Editing the programs
Editing with the operator mixer
In the OPERATOR MIXER section, you can use the RATIO OP 1–6 knobs [3] to edit
the pitch parameters for each operator, and the LEVEL OP 1–6 sliders [4] to
edit the output levels.
- Turn the PROGRAM knob [6] to select a program to edit.
- Move the RATIO OP 1–6 knobs [3] and the LEVEL OP 1–6 sliders [4] of the OPERATOR MIXER.
The effect will change depending on whether the operator you are editing is a carrier (the RATIO knob LED will light up red) or a modulator (the RATIO knob LED will light up blue).
RATIO knob [3]: Changes the pitch of each operator. Mainly the pitch changes for carriers, and the brightness of the sound or the position of harmonics changes for the modulators. Raising the pitch of a modulator will emphasize the sparkling harmonics that are characteristic of FM tone generators.
LEVEL slider [4]: Change the output level of each operator. The volume changes for carriers, and the brightness of the sound or the strength of the harmonics changes for the modulators. When the carrier is in FM mode and the output level of the modulator is brought way up, you can get a heavily distorted sound that’s something like a distorted guitar.
Easy program editing
You can edit the main parameters besides those of the operators in the HOME/
ALGO page.
-
Press the ALGO button [10] to
display the HOME/ALGO page. -
Use the DATA ENTRY A–F knobs [12] to change the values for the parameters shown on the display.
ALGO: Select the algorithm that determines the structure for operators 1–6 from the presets and user algorithm. ATK: Sets the attack time (how quickly the note starts) for all operators. DECAY: Sets the decay/release time (how quickly the note fades out) for all operators. FX1–3: Although the way this works depends on the effect type that is set, this mainly changes the depth of the effect.
Randomized editing
This sets the current program’s parameters in the selected scope to random
values.
Use this to find new inspiration when you are creating sounds.
- Press the button [14] to display the Randomize page.
- Select the scope of parameters to randomize. Change the SCOPE parameter with the DATA ENTRY A knob. PROGRAM is selected by default, meaning all of the program parameters will be randomized.
- Press the YES button [8] to show a confirmation message.
- Press the YES button [8] again to randomize.
Detailed editing
You can make detailed edits as follows.
-
Press the desired PAGE SELECT button [13] between the MODE and EFFECT buttons to display the corresponding page. To display one of the secondary pages as shown below the buttons, hold the SHIFT button [16] down and select the desired page.
-
Sometimes the left side of the screen will indicate that multiple subpages are available. You can use the PAGE < and > buttons [7] to cycle through them.
-
You can edit the parameters for each operator on the MODE, PITCH and LEVEL pages. Use the OP SELECT + and − buttons [18] to select the operator to edit.
-
Use the DATA ENTRY A–F knobs [12] to change the parameters.
Each page’s editable parameters are shown below:
MODE: Change the operator mode and output waveforms for OP 1–6.
PITCH: Change the pitch of OP 1–6, as well as the pitch modulation from the LFO/EG.
LEVEL/EG: Set the output levels, EG and key tracking for OP 1–6.
MOD: Configure LFO 1–3 and EG 1–3.
FILTER: Set the overall filter used for OP 1–6.
EFFECT: Used for selecting effect types or making detailed edits to the effects.
ARP: Configure the arpeggiator.
SEQ: Used for setting how the sequencer operates, and for making detailed edits to the sequence data.
VOICE: Set whether a sound plays in mono, poly or unison mode.
V.PATCH: Specify the destination and depth of the effect produced by the LFO, EG and other modulation sources.
MISC: Used for changing other program parameters. You can copy operators on the OP UTIL page.
GLOBAL: Used for configuring the overall instrument. The settings you make in this mode are not saved to a program, but instead apply to all programs. Any changes you make will be saved automatically.
Tip: For details on each parameter and for more information on the effect parameters, see the Owner’s Manual (PDF).
Saving a program
Save any programs to the opsix that you have edited.
Any edits you make will be lost if you turn off the power of the opsix or
select a different program before saving the data.
-
Press the WRITE button [15].
The opsix will enter program save standby mode, and the YES and NO buttons will blink. -
Change the program name as necessary.
PROGRAM knob [5]: Changes the character at the cursor position.
SHIFT button [16]: Changes the type of character to input.
PAGE < and > buttons [7]: Moves the cursor. Hold down the SHIFT button while pressing the PAGE < button to delete the character at the cursor position.
Hold down the SHIFT button while pressing the PAGE > button to insert a blank space at the cursor position.
DATA ENTRY A–F knob [12]: Turning this knob left or right is the same as pressing the PAGE < and > buttons in succession. -
Press the YES button to confirm the program name.
-
Turn the PROGRAM knob to select the program location to which will save your edited sound.
Select a different program if you wish to keep the original program.
Tip: Press the NO button to cancel. -
Press the YES button to save the program.
The program will be saved, and the message “Write Completed” will be shown in the display.
Never turn off the power while a program is being saved. Doing so may corrupt the internal data.
Using the step sequencer
The opsix has a polyphonic sequencer that features up to 16 steps. Sequence
data for the step sequencer can be saved in each program. In addition to note
data, you can also record and play back motion sequences (these are changes
made to the sound using the knobs or sliders on the opsix).
Playback and recording on the step sequencer
Here we will play back the sequence data recorded for each program.
-
Press the PLAY button [22].
The sequence data recorded for the currently selected program will play. -
Press the REC button when you want to record what you play on the keyboard.
The REC button [23] will light up, and all notes that you play afterwards will be recorded as sequence data. Press the REC button again to finish recording. -
To stop sequence data playback, press the PLAY button again.
NOTE: Any data you record will be lost if you turn off the power on the opsix or select a different program before saving the data. → “Saving a program”
Step recording
-
Press the SEQUENCER/FAVORITES MODE button [21] to select SEQUENCER.
-
Select a program, and then press the REC button.
The STEP 1 button will blink. -
Use the STEP 1–16 buttons [26] to select the steps to input.
The STEP buttons that you select will blink. -
Press one or more keys on the keyboard at the same time to record one or more notes at the current step.
Press one of the STEP 1–16 buttons while holding down a key to record a tie.
The tie will connect the note to the step you pressed. -
When the set number of steps have finished recording, step recording will automatically end (the REC button will go dark).
Press the REC button during recording to stop recording midway. -
After you have finished recording, save the program.
If you select another program before saving your edited program, the sequence data in the newly selected program will be recalled, and the sequence data you recorded will be lost.
Saving a program will overwrite the sequence data at that program location.
Other functions
Restoring the opsix to factory-set default settings
To restore the opsix to its factory default state, turn on the power while
holding down the SHIFT and WRITE/RECALL buttons. See the Owner’s Manual (PDF)
for details. Never turn off the power while data is being loaded. Doing so may
corrupt the internal data.
Specifications
Keyboard: 37 keys (velocity and release-velocity sensitive)
Maximum Polyphony: 32 voices (the maximum number of voices depends on the
settings)
Sound generating system: Altered FM sound generator
Number of programs: 500
Inputs/outputs: Headphone (6.3 mm stereo phone jack), OUTPUT L/MONO and R
(impedance-balanced 6.3 mm TRS phone jacks), DAMPER (6.3 mm phone jack, half-
damper not supported), MIDI IN and OUT connectors, USB B port Power supply: AC
adapter (DC12V, )
Power consumption: 5 W
Dimensions (W × D × H): 565 × 338 × 90 mm/22.24″ × 13.31″ × 3.54″
Weight: 2.9 kg/6.93 lbs.
Included items: AC adapter, Precautions, Quick Start Guide
Accessories (sold separately): DS-1H damper pedal, PS-1 pedal switch,
PS-3 pedal switch
- Specifications and appearance are subject to change without notice for improvement.
- All product names and company names are the trademarks or registered trademarks of their respective owners.
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