Alesis K2661 specifications Next page shows a schematic overview of studio structure

Basic Effects Mode

The Structure of Kurzweil Digital Effects (KDFX)

Each of the FXBuses contains its own signal-processing program, called an FX preset. Each

FX preset has a set of parameters: for example the RT60 value on a reverb, or the Feedback level on a delay line. These parameters can be fixed as part of the FX preset, or they can be externally controlled, from one of two different places. The four FXBuses are also called Insert FX, because in a conventional studio, that’s where they would be found: in the insert loop of a mixer, between the channel input and the Mix bus.

There is also a fifth FX preset, which is located on the Auxiliary FX Bus (the Aux bus). The Aux bus follows the four main FX presets in the signal path, and is normally configured as a global processor.

Each FX preset consists of an algorithm, modified by user-definable parameters. An algorithm is a processing function, like a reverb, flanger, or compressor; or a combination of processing functions in a particular order, like a flanger followed by a delay followed by a reverb. The algorithms themselves are fixed in ROM, like Kurzweil ROM samples, but you can change the values of their operating parameters.

Each algorithm requires a certain amount of processing power, which is expressed in Processing Allocation Units (or PAUs). Simple algorithms require 1 PAU, while more complex algorithms require up to 4 PAUs. The amount of processing power available in each FX preset is set by its Allocation parameter. When you are selecting an FX preset for an insert bus, the number of PAUs its algorithm requires appears on the display, so you can keep track of how many PAUs are in use.

PAUs are shared among the four insert buses. There is a limit to the total number of PAUs that the insert buses can use, and that limit is four. PAUs can be manually preassigned to specific FXBuses, or using “Auto” mode they can be assigned automatically as FX presets are assigned to the buses. The Aux bus has a separate set of PAUs—three of them—which are not shared with the insert buses.

Finally, the outputs of the FX presets are passed through to an output routing system—as specified by the settings on the OUTPUT page in the Studio Editor—where they are sent to the physical outputs of the K2661.

The following equation summarizes studio structure:

Studio = EQs + Input-page settings + FX presets + Output Editor settings

The next page shows a schematic overview of studio structure.

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