8 - Preset Edit
Modulation Processors
O The 4x Amp can be used to get more steps or increase the interval of the quantizer.
O Experiment with this patch by connecting other sources and destinations to the quantizer.
The Quantizer can generate interesting whole-tone scales when envelope generators or LFOs are routed to the input. The quantizer turns a smoothly changing input signal into a series of steps. By routing the output of the quantizer to Pitch and adjusting the cord amounts, you can control both the number of steps and the pitch interval of each step.
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Quantizer |
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The input cord amount controls how many steps are generated. A sawtooth wave (LFO+) feeding the input, and the cord amount set to 100% generates sixteen steps. The output cord amount controls the size (or interval) of the steps.
Try setting up the following patch exactly as shown below using your favorite preset as a starting point.
This patch generates an ascending arpeggio every time you press a key. The block diagram of the patch is shown on the following page. The patch is very straightforward except for the DC offset which was added in to bring the pitch down into tune. (Sometimes you have to fix a problem, but using the mod processors there's usually a way around it to achieve the desired result.)
EOS 4.0 Software Manual 267
8 - Preset Edit
Modulation Processors
LFO+ |
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You can probably start to see some of the possibilities (and there are many). Whenever you find yourself wishing for some esoteric type of control, take a minute and think if there is a way to achieve the desired result using the modulation processors.
8 - Preset Edit
Dynamic Filters
Dynamic Filters
Following is a block diagram of the signal path.
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Pitch Glide Retrigger Glide
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A Low Pass filter is a powerful synthesizer filter which can dramatically alter the sound of a sample.
To understand how a filter works, we need to understand what makes a sound wave. A sine wave is the simplest form of sound wave. Any waveform except a sine wave can be analyzed as a mix of sine waves at specific frequencies and amplitudes.
Any waveform can be analyzed as a mixture of sine waves.
EOS 4.0 Software Manual 269
8 - Preset Edit
Dynamic Filters
One way to represent complex waveforms is to use a chart with frequency on one axis and amplitude on the other. Each vertical line of the chart represents one sine wave at a specific amplitude and frequency.
100
Frequency vs Amplitude
80
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40 80 160 360 720 1440 2880 ...
Frequency
What is a Filter?
Most samples are complex waves containing many sine waves of various amplitudes and frequencies. A filter is a device which allows us to remove certain components of a sound depending on its frequency. For example, a Low Pass Filter lets the low frequencies pass and removes only the high frequencies.
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40 80 160 360 720 1440 2880 ...
Frequency
8 - Preset Edit
Dynamic Filters
A filter that lets only the high frequencies pass is called a high-pass filter.
Initial Frequency
Filter Output
High Pass
Filter
40 |
80 |
160 |
360 |
720 |
1440 2880 ... |
Frequency
A filter that only lets a certain band of frequencies pass is called a band-pass filter.
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Center Frequency
Filter
Output
Band Pass
Filter
40 |
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720 |
1440 2880 ... |
Frequency
A Notch Filter is just the opposite of a bandpass filter and is used to eliminate a narrow band of frequencies.
Another control found on traditional filters is called Q or resonance. A lowpass filter with a high Q would emphasize the frequencies around the cutoff frequency. The following chart shows how different amounts of Q affect the low pass filter response. In terms of sound, frequencies around the cutoff tend to “ring” with high Q settings. If the filter is slowly swept back and forth, with a high Q, various overtones are “picked out” of the sound and amplified as the resonant peak sweeps over them. Bells and gongs are real world examples of sounds which have a high Q.
EOS 4.0 Software Manual 271