Propellerhead Reason tutorials made by Hydlide

Published on Reason Experts

Essential LFO tricks in Reason

Published: 2017-07-02

One of the most overlooked tools in Reason are the build in LFO (Low frequency oscillator) from native stock devices such as the Subtractor, Malstrom and Thor. In this article Hydlide will mainly look at the powers of the subtractor LFO. The example files in this case are custom combinator patches (which should load up in Reason 5 even). The LFO in the subtractor has its charm and comes with patterns like triangle, Ramp, reverse Ramp, Square, Random and Drift. The LFO2 is often not being touched, yet this one has some quite interesting tricks to use in certain sound design techniques. We'll be touching different segments for different LFO settings and types in a linear direction. This might shed some light on what you can do with an automated pattern inside a synthesizer like the Subtractor in Propellerhead Reason.

LFO to pitch

Using an LFO to Pitch can be useful from time to time alter the pitch of an oscillator in a linear direction. The most interesting ones for using Pitch are either the LFO patterns Square and drift (that is the last pattern in the LFO1).

To move 6 notes up and down, the LFO pitch amount needs to be set to 82. 
To move 12 notes up and down, the LFO pitch amount needs to be set to 104

The reason for me posting these number is because of that typical chip tune sound you can create in Reason. The set up goes as followed:
- Create a combinator patch (this is optional though)
- Create a subtractor
- Initialize the patch / reset the device (Under menu Edit > Reset Device)
- Set the LFO 1 to square
- Set the LFO 1 amount to 104 (=1 octave)
- Set the oscillator to square as well

LFO to Square - Subtractor Chip tune

In this case the LFO will change the pitch of oscillator one and oscillator two going up and down with one octave. The rate in this case will determine how fast these pitch changes are going. This is a common technique that is applied in Chip tune sounds or Sid chip music.


A different take on using the LFO to pitch is using the "drift" setting. Drift is the last pattern in the LFO 1. These type of patterns are ideal to make a digital sound turn in to a more analog type of sound effect. The benefit behind 'drift' is that it act quite similar as Random, but changes the pattern with gradual changes. Thus ideal for making minor changes in the pitch, giving it that little analog type of feel in the synth itself.

To set this one up go for the following steps:
- 1. Create a combinator
- 2. Create a mixer 6:2 inside the combinator (we'll be using 2 subtractors just to give it a bigger sound)
- 3. Create a subtractor
- 4. Reset the device
- 5. turn on Oscillator 2
- 6. tune oscillator two a little bit different (I am going with semi one octave lower, and a cent setting of +2)
- 7. LFO 1 mode to drift
- 8. set and amount around 10-ish (not too much)
- 9. Set the LFO 1 to Osc 2 (which alters the pitch of oscillator 2 only)
- Repeat step 3 till 9 to create a second subtractor in this combinator patch
- Last, pan the mixer 6:2 so subtractor 1 goes over left, while subtractor 2 goes over right

Analog subtractor using LFO

Also, one might tune the oscillators on the second subtractor a bit different and the LFO rate / amount may vary from subtractor to subtractor. To save you some time, you can download the following combinator patch:


With these type of setups (especially with the subtractor synthesizer that is), there are a few interesting things happening. First of all, the subtractor is a free running oscillator. Meaning, every time you load the device inside the Reason Rack the wave form will have a different start offset. Thus every time you play this synthesizer, it will sound different from oscillator to oscillator. This idea gets enhanced by the usage of two subtractors with the exact same wave forms. By spreading the out over left vs right (by default even), the sound will travel different over left vs right. By adding that additional drift LFO + pitch change amount we increase the changes that the sounds will be driven off tune from one oscillator to another. And this happens with an additional random state.

LFO to Gated Filter

A different applicable usage on LFO is triggering a gated LFO to Filter. This can be done by using either LFO Ramp down or LFO Square. There is a difference between the two, since Ramp down will in this case gradual move the filter from up to down. While Square will turn the filter on / off (depending on the LFO amount). These set ups are ideal if you are lazy on just want one key trigger to take of everything regarding to the rhythm. 

Gated LFO

All you have to do is set up the filter as a sustained filter (Sustain goes all the way open on the filter envelope). Next up you set a filter frequency on the low pass filter. And last you set the LFO to filter with an amount. 


LFO 1 to Mix

Similar as using the first example (LFO to square), you can use the LFO1 mix setting to balance between Oscillator 1 to Oscillator 2 in a random state. While sometimes it makes sense to do this in a sequenced method (using Square), sometimes mix settings can be interesting when playing pads or organic sounds. So the mix setting is quite an interesting setting to use from time to time. Especially when you use different wave forms with different time signatures in the LFO. Explaining the step by step guide will take me some time. But in theory: you create a subtractor with 2 oscillators. The default mix setting goes on 0 (since the LFO will do most of the work). The LFO type will be set to drift. And the wave forms per subtractor will vary.


While I haven't touched phase in this context yet, I will safe that story for a different article.


Published on Reason Experts
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Published on Reason Experts
Published: 2017-07-02

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