Friday, December 14, 2012

#7. Synthesizers in Reason - Thor

Note: It will be a good idea to look at “Basic synth concepts”, “Subtractor” and “Malström” tutorials first if you haven`t done that already.


Reason Thor Synthesizer


Thor is the biggest synth beast in Reason. This monstrosity has 6 oscillator types and 4 different filter types + shaper, modulation matrix, a sequencer and so much more... There is a lot of explaining ahead of us, so let`s begin right away.

Let`s expand Thor with the Show Programmer button. We are going to look at the oscillators section. The common things between each of them are the following: Kbd knob which determines how strictly the Thor is going to follow the notes we input – it is turned all the way to the right by default. If we turn it all the way to the left we will disable key tracking. The other three knobs are the standard Pitch transposition, Semi tone change and Tune. You can run from 0 to 3 oscillators at once with one instance of Thor.

OSC Types:

thor oscs

Analog Oscillator

It has the standard basic waveforms with the option to manipulate the pulse width of the squarewave. According to PH, those waveforms differ from their twins in Subtractor.

Wavetable Oscillator

This osc looks a little bit like the PPG Wave 2. It has 32 selectable wavetables (each with different amount of waveforms in it) and a Position knob which slides between them (if you are into dubstep, this is a knob you might consider automating). Xfade is cool thing which allows you to make a smooth transition through the waveforms. If you turn it off, the Amount will change the waveforms abruptly.

Phase Modulation Oscillator

This synthesizer is similar to Casio CZ series synthesizers. They were a much cheaper way of creating diverse waveforms and filtering effects than the expensive analogue solutions. The phase modulation is achieved by manipulating the clock rate of a waveform. For example, if you manipulate the timing of a sinewave – playing its beginning fast, while holding its maximum value for a longer time, you will end up with a square wave. The waveforms are created using such techniques.

phase modulation thor explained

The PM knob acts like a filter morphing the original sound into a different one. In Thor Phase Modulation osc we can combine two waveforms (played in series, not mixed, the second one adds a fundamental 1 octave below the original pitch – this type of synthesis can`t be done with analog synthesizer) – the first has 8 variations and the second has only the first 5 without the last 3 (which simulate resonance). The second waveform can be turned off if necessary. 

FM Pair Oscillator

This is Frequency Modulating oscillator with modulator Mod (which effect is controlled by the FM knob – if it is at 0 no modulation is occurring) and Carrier sine waveforms. The numbers determines the frequency ratio between the two.

Multi Oscillator

This oscillator uses multiple detuned oscillators with detuning amount set by the Amt knob. It has 5 different waveforms and 8 detuning algorithms. The first two detune the oscs randomly. The Interval detunes each oscillator evenly in cents while Linear does that in Hz. FifthUp moves the oscs tuning five semitones above at maximum amount – both sets of four oscs are slightly detuned. At maximum value OctUpDn detunes half of the oscs up an octave and the other half – down an octave. It also detunes slightly the both sets of four oscs. In all of those, the 0 amount means no detune. In the last two (at 0 value) – Fifth and Octave half of the oscs are tuned up – by approx. a fifth or approx. an octave respectively. Turning the amount knob makes a random detuning of the oscs in both detuning algorithms. 

Noise Oscillator

The noise oscillator has 5 modes – the first 4 of which have controllable features with a modifier knob. Band – at knob put on 0 pure noise is heard – turning it to the right narrows the bandwidth. SH is “Sample and Hold” mode (a type of random generator) – the knob controls it`s rate from a random noise to a slightly phased colored noise. Static produces a static noise. The knob controls it`s density. Color makes colored noise - the modifier knob makes a white noise at max or boosts the low end at min. The last mode is for white noise in which all the frequencies are equally high.

thor am syncOn the left side of the oscillators we have additional types of modulating options. The AM is Ring Modulation (type of Amplitude Modulation). When you turn the slider up the result will consist the sum and the difference of the two osc`s frequencies. The first osc is the carrier while the second is the modulator. In Osc Sync one oscillator`s waveform (the master (osc 1)) will restart the period of another oscillator`s waveform (the slave (either osc 2 or 3)). The slider determines how pronounced he effect is going to be (you need to light the arrow in red in order to hear the effext).

If you want to hear the output of any of the oscillators, you`ll have to turn on the buttons with their numbers in the right – either from those above (which pass the oscs through the Shaper and Filter 1 one if turned on) or those below (passed through Filter 2 if turned on). If we select the same oscillator from both sets of buttons we will hear it twice (note that you may have to turn on some the arrow buttons first). You can route both sets of oscillator buttons separately or route the first one through the second one.

Thor internal routing example

In this example we route osc 1 and 2 through Filter 1 (set to Low Pass Ladder) and another parallel clean unaffected copy of osc 1 below (since Filter 2 is disabled). If we switch the left arrow located below the Shaper, the first two oscs will pass through the Filter 2 slot, with the copy of osc 1 in series rather then in parallel. We can apply additional filtering by selecting one of the four available filter types in the Filter 2 slot.

The Mixer section has a knob determining the relationships between osc 1 and osc 2. The first slider determines the level of both of those oscs while the second slider determines the level of osc 3.

Before Filter 3 you have another Gain controlling all of the oscs before with Velocity sensitivity setting and a Pan setting. Thor also has a big global Master Level knob.

thor levels

Thor can run 3 filters in one instance – one for each set of osc buttons and a one global. The first 3 types of filters are very similar – all of them have Frequency and Resonance knobs, Kbd track and Filter envelope amount which can be Inverted or controlled by Velocity. Drive sets the input gain to the filter. They can also self-oscillate – this adds a feedback whistling character  to the sound and can be heard when the Resonance knob is high. It is an attempt to emulate a filter effect found in some vintage synths like Moog.

Thor filter types

The Low Pass Ladder filter has 5 different dB settings – 6, 12 and 18 dB (inspired by Roland TB-303). Type I of the 24 dB filter puts the building shaper (self osc) after the filter output and before the feedback loop, Type II is before the filter input and after the feedback loop.

The State Variable filter offers the standard LP, HP, BP and Notch filters + a Peak one. Last two have an Amount knob determining on which side of the frequency spectrum will the effect be applied to.

The Comb Filter is similar to that in Malström, but with more rough characteristic.

The last type of filter is the Format Filter which makes a vocal type sound filterings. The Gender knob changes the timbre from male to female sounding output. The X and Y sliders controls the effect. The Env, Vel and Kbd parameters affect only the X slider.

Like Malström, Thor also has a Shaper, this time with 9 different types of distortions. To activate it, light up its small button left from Shaper.

shaper


Thor has two similar built in effects – Delay and Chorus (mono in – stereo out, if modulating external devices). Delay produces echo type of sounds while Chorus produces chorus FX with its faster delay time. They have Time parameters (Delay in Chorus) (the more to the left, the quicker the effect), Feedback knobs, determining the intensity of the repeated sound, Rate of the effect and it`s Amount. Dry-Wet determines how much of the original unprocessed “dry” sound is mixed with the affected “wet” sound.

thor delay and chorus effects

Thor has a Portamento switch – the first position turns it off, the second turns it on and the auto applies it only when multiple notes are being played. It has also an amount knob (Portamento).

portamento

Thor has 4 types of envelopes – the Amp, Filter and Global (for the global filter) ones are used to affect as target the destinations which are implied by their names. The Mod Envelope can be assigned to different targets using the Мodulation Мatrix below. Note how the Global Filter has DAHDSR envelope – the D stands for Delay, or how much time should pass for the Attack to come after the key is being pressed and held, H (Hold) holds the sound at maximum point for a certain amount of time.

thor adsr

LFO1 is standard per voice LFO with 18 modulating waveforms. LFO2 is a global LFO. Both can modulate characteristics of the sound from the Mod Matrix below.

lfo in thor

The Modulation Matrix has the following sections – Source (the modulator), Amount (the amount of modulation + or -), Destination (the target of the modulation) and Scale (with its Amount) modulating the Amount of the Source. You can see that there are vast possibilities for control with the many different types of sources and destinations. For example, you can set LFO1 as Source with 100% Amount to control Osc 1 -> pitch. Than you can modulate the LFO1 rate (as second Destination) with LFO2 (as second Source). The possibilities are endless. The Modulation Matrix is the thing that allows you to use the free Rotary 1 or Rotary 2; Button 1 or Button 2 modifiers. 

modifier button and knobs in thor

You can even route them to some of the 4 CV out as Destination to control external devices with them (for example controlling the first knob of many Combinators only with one of the Thors modifier knobs using CV Merger and Splitter).

modulation matrix in Thor

On the right there are two variations of the mod matrix – one with 2 Sources and one with 2 Scales.

The clr buttons on the side quickly erase the modulation row.

Thor has 16 steps Step Sequencer. Their number can me reduced with the Steps knob (or by clicking on one of the little red lights above) or individual steps can be turned off by disabling the red square below them.

step sequencer in Thor

The first switch determines the movement of the sequencer. Repeat loops it, 1 shot plays it once and Step plays it step by step after each pressing of the Run button. You can also select a direction – either Forward, Reverse, Pendulum (forward-backward; Pendulum 1 repeats the first and last note when shifting direction, while Pendulum 2 doesn`t) and Random. You can also adjust the rate and tempo sync it if you want.

The next knob sets different properties of selected step in the sequencer. You can adjust the Note (with octave adjusting switch), Velocity, Gate Length (length of the step), Step Duration adjusting the step timing. Curve 1 and Curve 2 are Modifiers similar to the 2 free rotaries and buttons in Thor and are used to control different destinations through the Mod Matrix.

You can select weather you want to use the only the MIDI input to control Thor or the Step Sequencer from the Trigger above.


trigger selector in Thor

When you flip the devise with TAB you will see that there are many CV / Gate input and output options which are self-explanatory. You can modulate the sequencer with CV signals, or make it send ones. Note that the Audio Input options and the 3-th and 4-th Audio Output options must be programmed from the Modulation Matrix after the connection. For example, you can input sound from another synth and use the matrix to route it through Thor`s Chorus.


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