The LFO (Synthesis & Sampling)

The LFO

I've been doing alot of experimentation lately specificaly centering around creative use of the LFO, I'm not sure what started me off really... I think it might have been because I was listening to Tangerine Dream while reading the manual for a TB303. I started thinking about the way in which the LFO generated its signal and that lead me on to one thing and another...

To cut a long story short this is a brief explanation of what an LFO is, does and why it is an important tool for effective synthesis (or sampling):

Low Frequency Oscillator is one of those 'does what it says' components found in all modern synthesizers and it does exactly what it says, it generates a tone/signal/pulse just like your main tone oscilator(s) except this oscillator is confines to stricter parameters resulting in a slower wave.

The LFO will usually be lower than 20 Hz and the waveform produces will typically be sine-tri-sqr-saw waves although it will vary from instrument to instrument.

What will also vary is where you can 'patch' its output - this determins a number othings that I'll get in to in a bit.

So the LFO is basically another oscillator that produces a slower waveform whats special about that? - Unlike the other oscillators its output is not an audio signal that is to be shaped the LFO is the signal that drives the components that do the shaping.

It seems that every new piece of equipment or software if come across offer different ways to impliments its LFO (as in modular synthesis) so its best to think of it in terms of how its shape can be formed and manipulated. With a good grasp of how the LFO is basicaly behaving in real-time and how that is then influencing whatever device/module it is driving you can open the door top a world of new possibilities when it comes to shaping sounds and creating new ones.

Typical LFO controls:

• Waveform - The actualy shape may vary. This is actually quite important but distracting so I'll skip it as it will become apparent soon enough.
• Rate - The frequency or speed of the waveform generated.
• Amount - Also known as depth.

Once the LFO has been set to produce the desired waveform it is then routed (of patched) to a secondry device/module or for that matter anywhere that allows. The LFO signal can then be used to trigger notes, start sequences, modulate pitch/velocity, shape the ADSR anything you choose.

**Read my advanced LFO section**