Sub Ek is a simple yet powerful subtractive synthesizer. Subtractive synthesis begins with a harmonic-rich sound source and subtracts frequencies using filters – in this case, a Low Pass Filter, or LPF.
The waveform in the upper left is the principle wave – it has no volume control. Next to it is a second voice, whose volume control is in the middle of the module, labelled osc.
To the left of the osc knob is the shp knob. The shp knob controls the shape of both waves (square and saw only).
Below the shape knob is single knob labelled env which is the envelope control. Rather than having individual control over the attack, decay, sustain, and release (which would require more knobs), this control is optimized to give a wide variety of envelopes using just one knob. Under the env knob is a x10 button. When it is pressed (red), it multiplies the attack, decay, and sustain by 10 – useful for pads.
To the right of the env knob is the det knob, or detune. This detunes the second oscillator. This knob has a steep exponential scale between 0 and 10Hz of detune, meaning at 12 o’clock it is 1Hz instead of 5Hz, as a linear knob would be.
Under the det knob is the sub knob, which is a volume control for a sine wave sub oscillator. Sub oscillators can add heft to an otherwise thin-sounding synthesizer. You can, of course, change the waveform, but you must do so inside the module.
Under the sub knob is the dly button which, when pressed (red), engages a stereo delay effect. The effect is preset, but you can easily enter the module and change its settings to suit your purposes.
The res and frq knobs control the resonance and frequency of the 12dB/oct LPF. Under the frq knob is a tapped port for the envelope. Using envelopes to control a resonant filter is really where the most interesting, animated synth sounds arise from. By default, all of the parameters that sound the best using the one-knob envelope are already linked. You cannot feedback the output of the envelope to its own control because it will force itself to go to 0. The reason the sub knob is not controlled with the envelope tap is that all the control would do is put an exponential curve to the envelope – it’s less noticeable, and sounds similar if you simply turned the sub knob down.
In between the two waveforms is a nze button which, when engaged (red) adds white noise to the synthesizer. Added noise can make a digital synthesizer sound more “analog,” and overall makes synthesizers sound more “organic.” This is because noise is an inherent ingredient in all instruments – a violin wouldn’t sound like a violin without the soft scrape of the horsehairs across the string, which make a type of noise. You can access an internal trim level for the nze button inside the module to adjust the level to your tastes.
This synthesizer comes pre-routed and ready to go, meaning all you need to do to play it is open it up and attach a keyboard (or use the keyboard in the iOS menu screen).
The MIDI In module sends Sub Ek 2 signals: a gate (the top input: on/off with velocity) and Hz (the bottom input: the pitch or frequency of the note). Though they are unlabelled, you can easily tell them apart: the gate input/outputs light up easily and quickly at a press of a key. The light shows the relative strength of the gate – fully lit is a MIDI velocity of 127, and unlit is of course 0. The Hz input/output will just barely light for most of the keyboard until you get into the higher octaves.
By default, the MIDI In module is set to legato mode, but if you would like to set it to polyphonic, simply enter the MIDI in module and click on the keyboard node until you have the appropriate level of polyphony for your purposes. Keep in mind that more polyphony requires more processing power. Also, when in polyphonic mode, you will not see the envelope rising and falling over the knobs, and the wires connecting the envelope port to the knobs will thicken.
The outputs of the Sub Ek module go straight into an Audio Out module. To control the volume of the synthesizer, use the knob of the Audio Out module. If you do not wish to use the stereo delay effect, keep the Left and Right connections the way they are – although you are sending it to 2 channels, it will still sound like a mono synth.
The outputs will flash quickly between red and blue (positive and negative). Whenever you see an output like this, you know it is an Alternating Signal, or AS, which for the purposes of this library means that this is an audio path. You will notice that, without the dly button engaged, both outputs flash identically (though seemingly chaotically). If the dly button is engaged, you will see a difference between the outputs.
A red light under the volume knob will flash when you overload the output. The Audio Out module is equipped with a built-in limiter that keeps all ASs between -1 and 1. The light flashing is not a bad thing, but it does indicate that you’ve introduced digital clipping distortion into the line out. It is still possible, however, to clip your overall output if you have multiple Audio Out modules pulled up. For this reason, it is advisable to sum all outputs to one Audio Out module.
If you would like to use Sub Ek as a mono synthesizer with a delay effect, you can do one of two things:
1) Draw one output to both the L and R inputs of the Audio Out module. The top/bottom orientation of the outputs matches the top/bottom orientation of the delay effects inside the module.
2) You can also sum the delays together and send them to an output – this allows you to have a dual delay sound in mono. The easiest way to do this is to call up an Add node and sum the two outputs together into one signal and draw that mono’d signal into both the L and R outputs. This can be done internally or externally – it does not matter.
