Novation X-Station User Manual

Also see for X-Station: Supplementary guide Specifications

Contents

Novation X-Station User Manual Manual pdf 35 page image

LFOsLike the Envelope Generators, the LFO section on a synthesizer is aModulator. That is to say, instead of forming a part of the sound syn-thesis process, it is used instead to change (modulate) other synthesiz-er sections. For example, altering the Oscillator pitch or Filter cutoff fre-quency.Most musical instruments produce sounds that vary not just in volumebut also in pitch and timbre. Sometimes this variation can be quite sub-tle, but still contribute greatly towards shaping the final sound.Where an Envelope is used to control a one-off modulation whichoccurs during the lifetime of a single note, LFOs modulate by using acyclic repeating wave pattern. As discussed earlier, Oscillators producea constant waveform which can take the shape of a repeating sinewave, triangle wave etc. LFOs produce waveforms in a similar way, butat a frequency normally too low to produce an audible pitched vibrationthat the human ear can perceive. In fact, LFO actually stands for LowFrequency Oscillator.As with an Envelope, the waveforms gener-ated by the LFOs may be fed to other partsof the synthesizer to create the desiredmovements in the sound.There are two independent LFOs availablewhich may be used to modulate differentsynthesizer sections and run at differentspeeds. Use the LFO SELECT button toselect LFO 1 or LFO 2 for editing.A typical waveshape for an LFO would be a Triangle wave.Imagine this slow moving wave being applied to an Oscillator’s pitch.The result would be that the pitch of the Oscillator slowly rises and fallsabove and below its original pitch.This would simulate, for example, a violinist moving a finger up anddown the string of the instrument whilst it is being bowed. This subtleup and down movement of pitch is referred to as the ‘Vibrato’ effect.Similarly, if the same LFO were applied to the Filter Cutoff frequencyinstead of the Oscillator pitch, a similar wobbling effect known as ‘wow-wow’ would be heard.As well as LFOs being available to modify (or more commonly knownas Modulate) different sections of the synthesizer, additional Envelopesmay also be used simultaneously.Clearly, the more Oscillators, Filters, Envelopes and LFOs there are ina Synthesizer, the more powerful it becomes.MemoriesThe first generation of synthesizers, produced many years ago werelarge modular machines where each part of the synthesizer washoused in a separate unit (block). These blocks could only be physicallyconnected together by combinations of cables known as patch leads. Atypical sound produced by this method would often involve connectingdozens of patch leads.Every time a new sound was required, the leads would have to bephysically disconnected and reconnected. The positions and connec-tions of the leads would have to be noted down on paper if there was tobe any hope of creating that particular sound ever again ! If not recon-nected in exactly the same way, the sound would be lost forever.Modern machines such as the Novation KS 4 / KS 5 have all the blocksin one compact unit and the sound generating or modifying blocks arearranged in a sensible fashion. Front panel switches and knobs deter-mine how each block functions and where the sound modifying blockssuch as the LFOs and Envelopes are routed, instead of having to physi-cally connect them externally with cables.Additionally, The settings of these front panel controls (which of coursedetermine the current sound or ‘patch’) may then be stored in memorylocations in the machine which can be recalled at any time.SummaryAn Analogue synthesizer can be broken down into five main soundgenerating or sound modifying (modulating) blocks.1 Oscillators that generate Waveforms at a certainpitches.2 A Mixer that mixes the outputs from the Oscillatorstogether.3 A Filter that removes certain harmonics, which changesthe characteristic or timbre of the sound.4 An Amplifier that is controlled by an Envelopegenerator. This alters the volume of a sound overtime when a note is played.5 LFOs and Envelopes that can be used to modulateany of the above.Much of the enjoyment to be had with a Synthesizer is with experiment-ing with the factory preset sounds and creating new ones. There is nosubstitute for ‘hands on‘ experience. Experiments with altering knobsand switches will eventually lead to a fuller understanding of how thevarious controls alter and help shape new sounds.Armed with the knowledge in this chapter, and an understanding ofwhat is actually happening in the machine when tweaks to the knobsand switches are made, the process of creating new and excitingsounds will become easy - Have fun.SYNTHESIS TUTORIALLFOs - Memories - Summary• 35 •TimePitch