Introduction
The DSP-4 is a digital signal processor (DSP ) accessory for audio power amplifiers. It is designed to reduce the need for external signal processing while increasing overall system reliability through distributed intelligence. It is intended pri- marily for QSC’s CX, DCA, and Powerlight2 series amplifiers and mounts directly to the rear panel of the 2-RU, 2-channel models of these amplifiers (pre-August, 1999 date-code of the CX, DCA and Powerlight2, and all ISA models will require use of an external power supply). Use of the DSP-4 with Powerlight models requires remote mounting, external power supply and use of a special interconnect cable (PL6.0/9.0 only). Refer to the Appendix for application infor- mation. The DSP-4 can also be used with amplifiers that do not have a QSC DataPort (older QSC models, non-QSC mod- els) with a reduced feature set and remote mounting/exter- nal power.
The signal processing capabilities include Compres- sors, Limiters, multiple Parametric Filters, High- and Low- Pass Filters, Shelf Filters, Muting, Attenuation, Multiple Delays, Polarity Reversal, and Audio Routing. A new feature of the DSP-4 is amplifier output Power Limiting (QSC DataPort amplifiers only). Analog-to-digital and digital-to- analog converters are 24-bit resolution and 48 kHz. sam- pling rate. Post-processor audio outputs are daisy-chain- able for connection to additional amplifiers. Input sensitivity and output level is software selectable. Dynamic range is greater than 106 dB. Inputs are balanced and the post-DSP outputs are pseudo balanced.
Physically, the DSP-4 is a small module that “piggybacks” onto the back panel of the specified QSC amplifiers. It con- nects directly to the DataPort on the back panel and is secured with supplied hardware. When used with other
amplifiers, the DSP-4 is mounted remotely on a rack-mount accessory bracket providing a solid mounting platform. There are two LED’s; blue to indicate power status and green to indicate input signal presence.
Connections include an RS-232 port and a DataPort pass- through connector for use with QSC DataPort products . For non-DataPort applications, two XLR audio inputs and two XLR outputs (post-DSP) are provided. There is a power receptacle for use with amplifiers that do not provide DataPort power or with non-QSC amplifiers.
Control of the DSP-4is accomplished with the supplied QSC Signal Manager software and an RS-232 connection between the module and PC. The Signal Manager software provides an easy-to-use graphical user interface where DSP “objects” are placed onto a palette and connected. This interface allows for almost infinite configuration possibili- ties. Once the DSP-4 has been set up as desired and the configuration saved to the DSP-4, connection to the PC is no longer required. This feature allows essentially tamper- proof amplifier DSP set up. Further changes can be imple- mented in the field by simply connecting a PC and loading the new setup into the DSP-4.
Operation over an Ethernet network can be accomplished using QSC’s QSControl platform. Please refer to the soft- ware documentation (software Help file and Readme.txt file) for supported feature-set and operation information.
From all of us at QSC Audio, thank you for your purchase. Be sure to check our website at http://www.qscaudio.com for the latest software and firmware updates as well as sample DSP configurations.
