Oscillators explained

Propellerhead Reason's VSTi is a very general machine. The concepts behind all their designs are general purpose in the sense that these algorithms are a compilation of almost all that are used in other programs, hardware units, and synthesizers you can get on the market. Understanding the concepts behind them is important to being able to use them effectively on ANY machine, and this should not be taken as a specification manual geared directly toward Propellerhead's software.


Press the down arrow on one of the OSC slots. You will get a drop-down list of all the available oscillator generators within Reason. The differences between them are the way in which the waveform is generated. However, there will be 4 options common to all the oscillators - KBD, Octave, Semi, and Tune. KDB is the only one we haven't talked about yet, so let's define that.

KDB - Turning this knob all the way up will snap the frequency generated to it's corresponding note being played on the sequencer. If it is turned all the way down, you will always hear the note defined by the Octave/Semi/Tune knobs.

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oscillator types

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ANALOG:

The Analog generator is the most basic oscillator. It will produce one of 4 wave-types:
1 - Sawtooth
2 - Square
3 - Triangle
4 - Sine

NOTE: With the square, you are given the option to change the PW(pulse width). It does exactly as visually described on the knob. Using this will only help further fine-tune your instrument. I can only wonder why this option is not included for the rest of the analog waves... someone wasn't paid enough!
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 WAVETABLE:

Wavetable synthesis began with PPG Wave Computers in their PPG 2.x series and beyond, dating the methodology to 1981. It is interesting to note that almost all advancements in music production in recent times came about with the birth of the electronic age. There has been little innovation before OR after, due to constraints of technology. Rather, the biggest moves in the music industry have been in manipulating these age-old tools in new ways - something that would have sounded terrible in disco music in the 80s may now sound brilliant and a perfect fit in EDM music today.

Within the wavetable oscillator you have access to different wavetables. A wavetable is multiple sound samples digitally coded into a single file which are subsequently mapped out onto a mathematical table. Using the Position knob, you can browse through the different samples within the table. Pressing the "X-fade" switch on will have the program mathematically fade  between the different sample types instead of a sudden shift when changing from, say, a sine wave to a triangle.


Wavetables are designed so that you can map the ADSR envelopes(attack, decay, sustain, and release) to the position knob. For example: what this will do is that when you are attempting to replicate something like a trumpet, the initial attack of the note will be bright(timbre of a trumpet sound located at the top of the table), and will decay into the sustained body of the note which is naturally dull(bottom of the wavetable).

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PHASE MODULATION:

Phase modulation synthesis was developed by Casio in 1980. In computer terms, it is the manipulation of the processor's clock speed to produce new waveforms from simple analog ones. This can be best described as the sample is processed very fast, up until the highest point in the wavetable. At this point, the processor will then clock very slowly before returning to it's normal speed.

Take a look at the diagram on the right and you can see how a sine(green) can be morphed into a square(black) by slowing the clock speed at the highest point in the sine wave(red vertical lines).

In Reason, the clock-rate is modified by the PM(pulse modulation) knob. Like the Wavetable oscillator, you want to apply the ADSR envelopes or even an LFO onto the PM knob to get the most out of your synth.