8 - Preset Edit
Modulation Processors
Sum Node
Lag 0
Lag
Lag 0 in
OThe Lag Processors can also be used as 2 additional summing amps. Lag0in and Lag1in are available as modulation sources which are the sum of any cords connected to the Lag in destination. The summing amp is before the lag processor as shown above.
OA digital “1” is equal to the patch cord amount.
OThe Flip-Flop Footswitch will stay On until it is pressed again. Then it will toggle Off.
Modulation Processors
Modulation processors are devices which can modify modulation sources such as LFOs and envelope generators before they are applied to a destination. The modulation processors allow you to create patches and do tricks which would not be possible otherwise. The following modulation processors are currently implemented:
Switch |
Outputs a digital “1” when the input is greater than |
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“0”. |
Summing Amp |
Allows you to mix several modulation signals |
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together before applying them to a destination. |
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This saves cords when the output is to be routed to |
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multiple destinations. |
Lag Processors |
Slows down rapid changes in the input signal. |
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The output “lags” behind the input at a |
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programmed rate (set in the LFO 2 screen). |
Absolute Value |
This function inverts negative values presented to it |
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and leaves positive values alone. This device outputs |
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only positive values. |
Diode |
This function only allows positive values to pass and |
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blocks negative values. |
Flip-Flop |
The output of this processor alternates between a |
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digital “1” and digital “0” each time the input goes |
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positive from zero or a negative value. If an LFO |
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wave were input, the output would be a square wave |
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of half the input frequency. |
Quantizer |
With the input cord set to 100%, the output value is |
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limited to 16 discrete values (If the input = sawtooth |
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wave, then the output = staircase). The value of the |
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input cord controls the number of steps. The value |
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of the output cord controls the size of the steps. |
4x Gain |
This processor multiplies the input value by 4 to |
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amplify modulation sources. |
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EOS 4.0 Software Manual 263
8 - Preset Edit
Modulation Processors
Modulation processors are inserted into a modulation routing as shown in the following diagram.
The modular analog synthesizers of yesteryear were incredibly flexible, partly because processing devices could be connected in any order. Modulation processors are designed according to this modular concept. They can be linked and used in a wide variety of ways limited only by your imagination. Consider the following example:
Velocity ~ |
Switch |
Pitch |
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Cord |
Cord |
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Switch On when |
Switch value |
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Velocity > 0 |
is Scaled by |
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Cord Amount |
This patch would be programmed in the Cords screen as shown in the following illustration.
This particular patch shifts the overall pitch up a fifth when the key velocity exceeds 64. Velocities below 64 will play at normal pitch and velocities of 64 and above will be raised a perfect fifth. The Velocity “~” source scales the played velocity around zero. In other words, low velocities (below 64) will have negative values and high velocities (64 and above) will be positive. A velocity of 64 would be zero. The Switch module only outputs a “1” if the input value is greater than zero. This digital “1” value can be scaled through the attenuator on the cord to raise or lower the pitch by any amount. In this case, a scaling value of +22 raises the pitch by a perfect fifth. The amount of the patchcord on the input to the switch is unimportant because ANY velocity value equal or greater than 64 will flip the switch. If the input cord amount were a negative value however, the action of the velocity would be reversed and velocities less than 64 would raise the pitch and velocities equal or greater than 64 would play the original pitch.
But what if you wanted the velocity switch point to be something other than 64? Thanks to the modulation processors, it can be done. Here's how.
EOS 4.0 Software Manual 265
8 - Preset Edit
Modulation Processors
Velocity ~
Cord
21
DC
Cord
Switch On when Velocity > 0
Pitch
Cord
Switch value is Scaled by Cord Amount
1.Connect the DC level to the input of the switch along with the velocity value. Note that more than one modulation source can be applied to the input of a processor.
The value of the DC offset determines the velocity switch point and is adjusted using the patchcord's attenuator.
2.Set the DC amount to a negative amount, higher velocity values are required to trip the switch. Setting the DC value to a positive value brings the velocity switch point down.
Following is the Cords screen for this patch.
Another example routes the Pink Noise generator through one of the Lag Processors in order to derive a smooth random function. A smooth random wave is useful in small amounts to add a degree of natural variation to timbre when routed to filter cutoff. Normal pink noise is low pass filtered audio frequency noise with a 3 dB/octave slope to give equal energy per octave. Our pink noise is actually more like very low frequency filtered (mauve) noise, but it is perfect for use as a random control source.
Pink |
Lag |
Filter |
Noise |
Processor |
Cutoff |
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Cord |
Cord |
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Lag Smooths |
Smooth |
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Pink Noise |
Random Function |