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Using Manual LFO Speeds To Create Variation In Your Patches


Adding expression to our music is always welcome and if you are anything like me you’ll always be looking for new ways to make your projects more interesting. I’m a huge fan of using modulation for this purpose and one of the most useful modulators is the humble LFO or Low Frequency Oscillator.

LFOs are often hard synced to a DAWS tempo and all sorts of great rhythmic effects are attainable this way but an often overlooked technique is to use your LFOs in a free running mode. Let’s take a look at how we set this up in a popular soft synth and how we can use the effects produced…

Step 1: Setting Up The Raw Sound

First up you’ll need to choose the sound you are going to modulate and this case I’ve gone for about the most simple patch you can get. It’s simply a single un-filtered saw wave. In fact this is taken from the tutorial bank in Logic’s ES2 and as you might of already guessed this is the synth we’ll be using here.

I’ve simply recorded a single note 8 bars in length and ensured there is no modulation or processing being applied to our super simple patch. This is the perfect way to start any custom patch as ay changes can be heard clearly.

The basic patch used.

The raw patch plays back

Step 2: Engaging An LFO

Now we need to engage our LFO. This simply involves mapping the LFOs output to any destination in your synth. In this case I have mapped the LFO to the filter’s cut off frequency.

In the ES2 this is done by using the excellent mod matrix but this technique will vary depending on the actual synth you are using. Generally this process if pretty straight forward.

The mod matrix is initialised.

Once you have made this mapping you may start to hear some modulation occur , in the next step we’ll look at how you can start to control this and which parameters you should use.

The mapping is complete

Step 3: Standard Synced LFO Effects

The most common way of using LFOs is probably syncopating their movement with the BPM of the your current project. You can usually choose a musical measure within the LFO’s speed parameter. This tight syncopation will often produce great rhythmical effects and is a nice way to create an instant groove.

The LFO is set up to syncopate with the projects BPM.

You can hear an example of this below but we are going to take a look at how to use the LFO in a free running, non syncopated mode.

The synced LFO matched with a simple loop

Step 4: Free Running LFOs

When an LFO is set to a free running mode it’s speed is in no way linked to your project’s BPM and you can adjust the speed manually. This gives you a fair amount of freedom and allows you to experiment with anything from slow undulating effects right the way through to super fast vibratos and cross modulation.

Adjusting the LFO speed yourself is all very well but in most studio situations you’ll probably want to automate the effect so that you have absolute control over the sound throughout your project.

Step 5: Adding Automation To Introduce Variation

In this case I decided to demonstrate the effect by going from a very slow LFO speed to a pretty fast one and vica versa. This was achieved by drawing an automation ramp controlling the LFOs speed parameter.

The down ramp

The LFO moves from fast to slow

… And up ramp

The LFO now moves from slow to fast

You can hear that the effect is very different depending on which way you move and has all sorts of musical applications but is especially useful for builds, breakdowns and transitions. Obviously you might want to experiment with more complex patches and combine the end result with effects such as reverb and delay.

Below is a track I recently used this effect on, you can clearly hear a synth being manipulated using this technique just before the drums come in. Hopefully this will be useful to you and you can use it in your own productions.

An example of the effect in action

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