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Tutorial 6: EQ, Delays and Filters

What? Is granular synthesis not cool enough by itself? RTGS3 provides a few lovely effects which work well when used together with granular synthesis:

EQ

EQ

Equalization can be used to subtly adjust the spectrum of a sound (as we saw in Tutorial 4, Part 2), but it can also be used to create more radical effects. The EQ in RTGS3 can be set up to do either of these.

Step 1

Locate the EQ interface in the Effects section of the main window and activate it by clicking on its toggle:
EQOn

Step 2

Fill both buffers with pink noise at 80% amplitude (refer to Tutorial 0, Part 1 if you don't remember how to do this) and then set the Grain Envelope to a fast attack:
EnvelopeFastAttack

Click the "Generate a Grain" button a few times to get an idea of the type of grain you've just created.

Step 3

Return to the EQ interface. Click near the middle of the EQ graph and drag the mouse upwards until its setting looks like this:
EQMidBoostWide

Click "Generate a Grain" a few times again to get an idea of the change you made to the output sound.

When adjusting the EQ graph settings, you can drag the mouse up and down to set a band's amplitude, or left and right to set a band's frequency. Clicking on the edge of one of the bands lets you change that band's width.

Step 4

You can also set the EQ parameters numerically in the Graphic EQ Settings window, which you open by clicking the EQ's gear icon. Let's use this window to change one of the EQ band's width (also called its "Q"). Open the window and make the following settings to band 3:
EQBand3Narrow

You'll notice that any changes made in this window are reflected in the EQ graph. Click "Generate a Grain" a few times to get an idea of the changes you can make to the output sound.

You might wonder why the EQ settings can be controlled by MIDI, but not by one of the RTGS3 controllers. This is because some controllers can generate unexpected or extreme parameters (such as most of the Generators can). This in turn could cause the EQ to generate very loud output which is dangerous for both your ears and your equipment.

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Delays

For this part of the tutorial we'll continue using the settings from step 2 of the first part: Buffers filled with noise and Grain Envelope set to a fast attack.

Step 1

Turn On Delays by clicking its toggle in the Effects section of the main window, and bring its Dry/Wet Mix fader up to about 1/2 way:
DelaysOnHalf

Click the "Generate a Grain" button to get a first impression of what the Delays effect does.

Step 2

Open the Delays Settings Window by clicking the Delays' gear icon.

The RTGS3 Delays effect is simply a bank of 32 delay units, each with a unique delay time, amplitude and panning value. However you do not set these values directly: instead, each value is generated automatically based on the position of a 2D slider corresponding to that set of values.

Step 3

Let's modify the default settings to create a totally different kind of effect.

Set the maximum delay time to 250 milliseconds, and move the 2D slider so that the graph displays a diagonal line like this:
DelayTimes250ms

Move the Amplitudes 2D slider so that it displays a diagonal line similar to the one displayed above, and then click the "Center" button beneath the Panning graph.

Click the "Generate a Grain" button to hear what this setting sounds like. You'll notice that because the maximum delay time is very short a kind of comb filter effect is created.

Step 4

Let's try another setting:

Set the maximum delay time back to the default value (2000 milliseconds) and move the 2D slider so that the graph displays a curved line like this:
DelayTimesCurveDown

Now click the "Randomize" buttons for both the Amplitudes and Panning 2D sliders:
DelaysAmpPanRandom

Hopefully this gives you enough of an idea of how the Delays effect works. The 2D sliders provide enough control over the parameters to create interesting effects while saving you from having to input tedious amounts of values for each delay unit.

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Filters

NOTE: be careful with your ears and equipment! The Filters effect can be set to generate some very loud sounds concentrated at specific frequencies. Always bring the Master Gain fader down a little before switching Grains on or making a major change to any Filters values.

For this part of the tutorial we'll again continue using the settings from step 2 of the first part: Buffers filled with noise and Grain Envelope set to a fast attack. Make sure to turn off the EQ and Delays effects before moving on.

Step 1

Turn On Filters by clicking its toggle in the Effects section of the main window, and bring its Dry/Wet Mix fader up to about 1/2 way:
FiltersOnHalf

Click the "Generate a Grain" button to get a first impression of what the Filters effect does.

Step 2

Open the Filters Settings Window by clicking the Filters' gear icon.

The RTGS3 Filters effect is simply a bank of 32 resonating filters, each with a unique frequency, amplitude and resonance value. However you do not set these values directly: instead, each value is generated automatically based on the position of a 2D slider corresponding to that set of values.

Step 3

Let's modify the default settings to create a totally different kind of effect.

Set the Frequencies Range to 50 to 5000 Hz. (You can do this by clicking and dragging on the values displayed beneath the 2D slider, or by clicking the values and then entering the numbers on the computer keyboard.)

Leave the Frequencies and Amplitudes 2D sliders at their default positions for now.

Click the "Maximize" button beneath the Resonances 2D slider. This will set the resonance value for each filter to its maximum value.

Click the "Generate a Grain" button to hear what this setting sounds like. You'll notice that the frequency spectrum of the effect is much larger now, and that the higher Resonances setting creates a longer decay time for the effect.

Step 4

If you now flatten the Amplitudes values by dragging its 2D slider up towards the centre (or by clicking its "Maximize" button) you'll notice that the lower frequencies have a much longer decay time. You can shorten the resonance of the lower frequencies by dragging the Resonances 2D slider all the way to the bottom-left corner:
FilterResonancesDiagUp

Step 5

Let's now make some changes to the settings to create a sound with a narrower spectrum and shorter decay.

Leave the Resonances 2D slider where it is, and move the Frequencies and Amplitudes 2D sliders both to the bottom right-corner. Change the Frequencies Range to 200 to 2000 Hz:
FilterFreqAmpExample

If you move the Filters' Dry/Wet Mix fader in the main window all the way to the right, you'll hear that with these settings the Filters effect transforms a noise burst into a sine wave.

I hope you enjoyed these tutorials, and that by doing them you've discovered something about the richness of granular synthesis techniques. There is a vast world of sounds and music that can be generated by RTGS3, and while these tutorials may have only scratched the surface they should have equipped you with the basic information you need to explore this technique to its full potential.

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