Spiral Synth Manual
Menu items
Introdution

Starting off

Oscillators

Envelopes

Mixers

The Filter

Routers

The Patch Bank

Introduction
This is a quick guide to Spiral Synth, and how to get cool sounds from it.
Starting off
To begin with, you'll have to make sure Spiral Synth is working correctly. (this assumes that you've built it, and its running Ok on your system).

If your experiencing jitters in the sound - like a skipping CD - it will most probably because the synth is using too much processor, and can't process the sound quick enough to play it properly. You can reduce the load by altering the .Spiralrc file - see the README for details on this.

Oscillators
The Oscillators are the source of the sound in SpiralSynth. There are three different waveforms to choose from. Square and Saw - with Pulse Width, and Noise, with sample and hold.
The best way to see these waveforms is to tune the oscillator so it's in sync with the scope, and tweak the parameters.

The tunable waveforms (Square and Saw) also have a portmento slider, which slides the pitch between each note you press in a variable amount.

The dials on the right allow you to choose the octave of the note, and fine tune it. The Modulation Depth dial alters the depth of effect from the LFO or Envelope.

Envelopes
The Envelopes allow you to change parameters over time. The Attack slider defines how fast the level gets to full volume, Decay is how fast it gets to the Sustain level and Release is how fast the level drops off after the key has been released.

Each oscillator has it's own envelope which amplifies it's sound, and there is an extra envelope which can modify parameters like filter cutoff, or oscillator pitch.

Mixers
The Mixers combine the sound of the oscillators. Set to add, they simply add together the sounds. Ring modulation multiplies one sound to another, this creates a third harmonic in the sound and is useful for simulating bells and chimes.
Cross modulation allows the input of one oscillator to modulate the frequency of the other. This is really quite an interesting feature, but you'll need to experiment with it to get good results.
The Filter
The Filter's purpose is to cut out some of the frequencies generated by the oscillators. The filter is a low pass filter, meaning it cuts out frequencies above the cutoff frequency.
The resonance boosts the frequency around the cutoff frequency, giving it that squeltchy sound.

The RvCMod and RvRMod buttons allow you to reverse the effect of any modulation on the cutoff or resonance, respectively.

Routers
The envelope router defines where the modulation from the LFO, or extra envelope will go.
The Patch Bank
The PatchBank allows you to save and recall patches you have created. It saves them in a file called .SpiralPatches.bank (in your home directory), which is really just a list of parameters in ASCII format.
To Load a patch, click on it's button. To save a patch, click on the (very small) save button on the left, and click on the button you wish to save to.
The number on the left shows which patch you've got selected. There are 100 slots to save patches in, but only 20 buttons on the panel. To get to the other slots use the dial on the right.

There is also a randomise button below the save one, which sets all the parameters to random values. This can create some very nasty noises, so keep the volume down!