Canadian Musician - November-December 2022 | Page 29

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Signal flow and patching
A semi-modular synthesizer is designed so that it will play sounds without patching anything . This is because there is already an internal signal routing in place between modules and functions in the synthesizer . When these default routings exist , we say they are normalled . However , these connections are also exposed on the synthesizer ’ s front panel . Plugging into a normalled patch point will usually ‘ break ’ that connection , letting you manually create new routings for audio signals and control voltages .
To break a normalled connection without adding a new signal , we patch in a dummy cable that ’ s not connected at the other end . Exploring your semimodular synth before adding patch cables will teach you when you need to establish new patch connections or not .
The patch panel on the MS- 20 ( above ) uses arrows and lines to show where signals fl o w .
For the sake of clarity , the MS-20 mini ’ s internally patched signal flow is illustrated below . Learning how these modules are represented on the patch panel of the MS-20 takes a bit of practice , but is well worth it .
On the ARP 2600 M , arrows illustrate which signal is normalled to go into a patch point , the slider that controls the amplitude ( level or amount ) of that signal , which module it is going into , and finally its output .
A note on inputs and outputs It ’ s important to differentiate inputs and outputs on synthesizers , and this can be done in a number of ways . On the volca modular , outputs have a solid color around them , and audio inputs and outputs have a circular shape beside them . However , as we ’ ll discover , some inputs on the volca modular can also be used as outputs – and vice versa !
On the ARP 2600 M and the MS-20 mini , the outputs are usually named output or out as there ’ s no coloring or distinctive labeling . However , you can easily see which signals are output , or normalled to an input , as arrows point from the source to the patch point .
These lines show the volca modular ’ s normalled signal flow . Note events ( Sequences ) control an envelope ( Function1 ), which then opens a low-pass gate ( LPG1 ) to pass the sound of the oscillator ( Source ) to the reverb ( Space Out ).
Replacing internal connections In the example to the right , the VCO-1 saw out on the ARP 2600 M is used to frequency modulate VCO-2 ’ s frequency ; plugging in that cable breaks the normalled connection to VCO-1 ’ s square wave .
In the example below , Function1 is only triggered every fourth time a key is touched , instead of every time .
This is a dummy cable !
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