DSP Usage

Extron ProDSP provides a large set of processing tools that can be used in many different ways to enhance and control your audio signals. Different tools can be used in different situations, but not all of the tools can be used at once. The Design Rule Verification utility should be used to help ensure that you have designed a configuration and set of presets that will work flawlessly.

Design Rule Verification

Each active processor uses a fixed amount of DSP processing power per processor block, unaffected by parameter settings. Every inserted processor is used in the calculation of DSP usage, whether it is bypassed or un-bypassed.  The DSP Configurator calculates usage of all active processors on the Line Output and Mic Input channels, plus the six most processor intensive Line Input channels. These six Line Input channels are constantly calculated in the DSP usage, since they have the potential to overload the DSP even if they are never used simultaneously. A DSP Usage Meter displays the results of this calculation in the bottom-right corner of the program screen.  

The DSP overloads when a combination of processors is enabled that totals over 100% usage. The DSP Configurator program prevents you from creating a configuration that will overload the DSP (i.e., put the DSP Usage meter above 100%) by disallowing certain operations. Elements within the GUI will become unavailable (gray out) when DSP usage reaches a point when those elements will cause overload. For example, when usage is above 90%, FBS processors will be unavailable. Copy/paste operations will be disabled (see next section, Overload Possible, for processor usage values).

It is possible, however, to create individual configurations and save them as presets, and then have a combination of presets cause the overload. To prevent of this type of situation, create a configuration and set of presets in Emulate mode, save the file, then run the Design Rule Verification utility as follows:

1. In Emulate mode, go to the Tools menu, and select Design Rule Verification.

2. The utility runs, reporting one of two results.

3. Design Verified Successfully

4. Overload Possible

Design Verified Successfully

When the Design Rule Verification utility determines that no combination of presets will cause an overload, the Design Verified Successfully dialog is displayed.

Overload Possible

When the Design Rule Verification utility determines that a combination of presets may cause an overload, the Overload Possible dialog is displayed, reporting the usage for each preset that contains DSP processing (presets that include ties only are not reported, since they involve no DSP usage).

There are two components reported with each applicable preset:

• Frees up to % - the amount that the given preset contents overlap with other presets. This content may contain active or empty blocks, hence the term, "frees up to." For example, if the amount is 0%, the given preset shares no processor content with any other preset, and when recalled, has the capacity to free 0% of processing. If the amount is 100%, the given preset contains all processing blocks, and when recalled, has the capacity to free up to 100% of processing, depending on how many active processing blocks the preset contains.

• Uses % - this is the total usage amount of the given preset, independent of processing content from any other preset. If the preset were recalled while a current configuration usage value of 0%, this is the amount that would appear as DSP Usage.

Usage Calculations

The following table shows DSP usage for each processor type, the maximum number of processors that can be active within a configuration or current state/emulation, and the potential DSP usage if all of those processors are active at the same time. Note that for a stereo channel (line input or output), each processor block utilizes two of each processor type.