QSC DSP-3 Digital Signal Processor
Amplifier Accessory Hardware Manual
Section 1: Introduction
Overview
The DSP-3 is a digital signal processor (DSP) accessory for audio power amplifiers, designed to reduce the need for external signal processing while increasing overall system reliability through distributed intelligence. It is primarily intended for QSC's CX, DCA, and Powerlight2 series amplifiers and mounts directly to the rear panel of 2-RU, 2-channel models. Amplifiers manufactured before August 1999 (CX, DCA, Powerlight2) and all ISA models require an external power supply. Use with Powerlight models necessitates remote mounting, an external power supply, and a special interconnect cable (PL6.0/9.0 only). The DSP-3 can also be used with amplifiers lacking a QSC DataPort (older QSC or non-QSC models) with a reduced feature set and remote mounting/external power.
Signal processing capabilities include: Input Compressor-limiter, multiple Parametric Filters, High- and Low-Pass Filters, a Shelf Filter, Muting, Attenuation, Multiple Delays, Polarity Reversal, Audio Routing, and Post Crossover Audio Mixing. Analog-to-digital and digital-to-analog converters offer 24-bit resolution at a 48 kHz sampling rate. Post-DSP output signals are daisy-chainable. Input sensitivity is selectable, and dynamic range exceeds 93 dB. Inputs and post-DSP outputs are electronically balanced.
Physically, the DSP-3 is a compact module that attaches to the back panel of compatible QSC amplifiers, connecting directly to the DataPort and secured with supplied hardware. For use with other amplifiers, the DSP-3 is mounted remotely on an accessory rack-mount bracket.
Connections include three D-sub type connectors: a DB-9 for RS-232 interface and an HD-15 for the DataPort interface. The unit also features four terminal block connectors for 2 audio inputs and 2 post-DSP outputs. A power receptacle is available for use when amplifiers do not supply power via their DataPort. Two LEDs indicate status: a blue LED for power status and a green LED for input signal presence.
Control is managed via the QSC Signal Manager software. Networked control through the QSControl platform is also supported. The software provides a graphical user interface for creating signal chains by connecting DSP "objects".
Connection to a host computer is made via a serial cable from the DSP-3's RS-232 port to the PC's COM port. Once configured and saved, the DSP-3 does not require a continuous PC connection for operation, allowing for tamper-proof setup.
Note: Powerlight 6.0 and Powerlight 9.0 amplifiers require pin #9 to be removed from the remote mounting interconnect cable to prevent amplifier damage. Standard VGA computer monitor cables often have pin #9 removed and are usable.
DSP-3 General Use Guidelines
IMPORTANT! Please read before operating the DSP-3 with your audio system.
The DSP-3 is a professional-level DSP product offering extensive configuration possibilities. Incorrect configurations can lead to unwanted signals or uncontrollable output. Signal Manager cannot predict the outcome of user-designed configurations.
To prevent damage to your sound system, especially when applying untested configurations or experimenting, it is strongly recommended to turn down the amplifier's physical gain controls. This mitigates risks from unexpected loud sounds or configurations that do not function as intended.
DO NOT CREATE SIGNAL LOOPS by feeding an output back into its own input, as this can create an oscillator that may damage speakers. Use the SINE AND NOISE GENERATOR OBJECTS WITH GREAT CAUTION, as they can produce signals harmful to speakers. Always turn down gain before using these objects. If a signal is not audible at expected levels, do not increase gain; investigate other potential issues to avoid sudden full-amplitude signals from loose connections.
The DSP-3 performs as instructed by its configuration; use caution to ensure desired outcomes.
Quick Start Guide
This guide is for users needing to get the DSP-3 and Signal Manager software operational quickly. It is not a substitute for the full hardware manual or software help file.
Step 1: Turn the Equipment Off & Install the Hardware
If you are using the DSP-3 with:
- QSC Powerlight2, CX, DCA 2-channel, 2-RU amplifiers (or later direct-mount applications): Mount the DSP-3 directly to the amplifier's DataPort and secure it with hardware. External power may be needed for older models.
- QSC 4-channel CX & DCA amplifiers (or later models with full-featured DataPort not supporting direct mounting): Mount the DSP-3 remotely. Connect a QSC DataPort cable between the amplifier's DataPort and the DSP-3's “backside” DataPort. External power may be required for older models.
- QSC Powerlight 6.0 or Powerlight 9.0: Mount the DSP-3 remotely. Connect a MODIFIED QSC DataPort cable (pin #9 removed) between the amplifier's DataPort and the DSP-3's “backside” DataPort. Connect the external power supply to the DSP-3's EXTERNAL POWER jack.
- QSC Powerlight (all except 6.0 & 9.0): Mount the DSP-3 remotely. Connect a QSC DataPort cable between the amplifier's DataPort and the DSP-3's “backside” DataPort. Connect the external power supply to the DSP-3's EXTERNAL POWER jack.
- A non-DataPort amplifier (QSC USA, PLX, or non-QSC models): Mount the DSP-3 remotely. Connect the DSP-3's CHANNEL 1 OUTPUT and CHANNEL 2 OUTPUT to the amplifier's inputs. Connect the external power supply to the DSP-3's EXTERNAL POWER jack.
Step 2: Connect the Computer to the DSP-3
Use a 9-pin serial data cable to connect the DSP-3's RS-232 connector to an available COM port on your computer (COM1 through COM16 are usable). COM1 is the default in Signal Manager. If COM1 is unavailable, select the appropriate COM port in the Signal Manager program after installation.
Step 3: Connect the Audio Inputs
- If using CHANNEL 1 INPUT & CHANNEL 2 INPUT connectors: Connect your input signal source to the terminal block connectors and plug them into the respective receptacles.
- If using the DataPort input (QSC CM16a or related products): Connect the DataPort output from the source product to the DSP-3's DataPort input using a QSC DataPort cable (male-to-male).
Step 4: Turn the Amp Gain Down, Power Up the Amplifier & the DSP-3
- If the DSP-3 requires external power: Apply power to the DSP-3 FIRST, then turn on the amplifier. Plug the power supply into an AC receptacle and connect the barrel plug to the DSP-3's EXTERNAL POWER jack. The blue POWER LED should illuminate. Use a tie-wrap to secure the power cord to the chassis.
- If the DSP-3 is powered by the amplifier's DataPort: Connect the amplifier to AC power and turn it on. The DSP-3's blue POWER LED will illuminate shortly after. If it does not, the amplifier may require an external power supply.
Step 5: Install the Software
- Insert the QSC Signal Manager CD into your computer's CD drive. The installation should start automatically. If not, proceed to step 2.
- Run D:\Setup.exe (replace D: with your drive letter) and follow on-screen instructions.
- Upon completion, you will be prompted to view the "Readme" file, which contains important up-to-date information.
- After installation, a "Signal Manager" icon will appear on your desktop. Double-click it to start the program.
- Access the "Help" menu to read the software help section, which includes this hardware manual for paperless reference. Visit qscaudio.com for updates.
- IMPORTANT! The DSP-3 ships with presets configured for full-range audio. This may not be suitable for your setup. Configure necessary crossovers, filters, etc., prior to applying audio signals to prevent equipment damage.
What the Signal Manager Application Looks Like
The Signal Manager application interface displays various panes and toolbars for configuration. Key elements include the Main Palette, Menu Bar, Drawing Tools Palette, Filters Palette, DSP Tools Palette, Misc Processors Palette, Inputs and Outputs Palette, File View Pane, Workspace Pane, Status Bar, Resource Meter Panes, Communication Status Pane, Cursor Position Pane, Splitter Bar, Configuration Status, Caps Lock Indicator, and Num Lock Indicator. The Workspace Pane is where signal paths are visually constructed by placing and connecting DSP "objects".
Step 6: Establish Communication Between the DSP-3 & the Computer
Check the COMMUNICATION STATUS PANE in Signal Manager. If it indicates ONLINE, your settings are correct. If OFFLINE, go to Tools > Options > DSP tab, select the correct COM port from the Serial Port Selection field, click OK, and restart Signal Manager.
Step 7: Ensure the Amplifier is Turned Down and You Have Suitable Speakers Connected
For familiarization, use full-range speakers and set the amplifier gain to a minimum useful setting. This allows configuration adjustments while verifying audio output. Small, high-power rated monitor speakers are ideal.
Safety Warning: Do not turn the amplifier gain up excessively. If communication fails, unexpected output transients could damage speakers.
Step 8: Create a Simple DSP Configuration
From the Menu Bar, select Configuration > New. On the Workspace, place an IN1 object from the Inputs and Outputs palette. Then, place an OUT1 object. Select the GAIN icon from the MISC PROCESSORS palette and place it between IN1 and OUT1. Use the DRAW tool to create "wires" connecting IN1 to GAIN, and GAIN to OUT1.
When the signal path is wired, select Configuration > Apply to DSP (or click the icon). This sends the configuration to the DSP-3. Outputs will be muted during loading. If audio is not heard, double-click GAIN objects to adjust gain. Input/output sensitivity settings in Tools > Options > DSP tab may also require adjustment.
The Communication Status pane should show "ONLINE" and Configuration Status "ACTIVE". If connection errors occur, check the RS-232 cable and COM port settings.
Repeat for IN2, OUT2, and a GAIN object for the second channel. Apply to DSP again.
The last applied configuration is saved and recalled upon power-up. To edit an existing configuration, select Configuration > Edit to unlock palettes, make changes, and then Apply to DSP.
This concludes the "Quick Start". Refer to the manual and software help file for more information.
Section 1: Introduction - Basic Connector & Indicator Descriptions
FRONT PANEL
CH 1 INPUT, CH 2 INPUT: These are 3-pin "Phoenix"-type (Euro-style) terminal-block jacks for line-level audio inputs. They are electronically balanced with an input impedance of 8.3k Ohms (3.7k Ohms unbalanced).
SIGNAL indicator: A green LED that illuminates when the DSP-3 detects an input signal on either channel. Dual brightness levels indicate signal strength: dim at -40dB, bright at -20dB.
DATAPORT: This is the "input" DataPort, used for connecting to QSC DataPort products that provide audio inputs or amplifier control/monitoring.
POWER indicator: A blue LED that illuminates when the DSP-3 has proper power applied.
CH 1 OUTPUT, CH2 OUTPUT: These terminal-block jacks provide post-DSP (processed) audio signals for downstream devices like amplifiers or monitoring busses. They can also be used for daisy-chaining to a second amplifier.
EXTERNAL POWER: A 2.5mm barrel connector (Center +, Outer -) for 15 VDC, 300mA. Use this if your amplifier does not supply the required operating voltage via its DataPort.
RS-232: A DB-9 female jack for connecting the serial cable to the computer.
Diagram Description: The front panel diagram shows the layout of these connectors and indicators on the DSP-3 unit.
REAR PANEL
DATAPORT (unlabeled): This is the "output" DataPort. It connects to the amplifier's DataPort when the DSP-3 is directly mounted on a 2-RU QSC DataPort equipped amplifier. For 3-RU amplifiers or remote mounting, a male-female DataPort cable is used. This connector is not used with non-DataPort amplifiers.
OVERALL
Diagram Description: The overall view diagram shows the DSP-3 unit from an angle, highlighting the placement of front and rear panel connectors and indicators.
Section 1: Introduction - List of Functions & Features
DSP-3 Hardware Features (full set available to QSC DataPort equipped amplifiers):
High- and Low-Pass Crossover
- Selectable responses: Butterworth (6,12,18,24 dB/octave slope), Bessel (6,12,18,24 dB/octave slope), Linkwitz-Riley (12 or 24 dB/octave slope).
- Graphical response curve provided in software.
- Adjustable frequency & slope.
- Ability to bypass all EQ with a single mouse click.
- Ability to add or delete EQ.
- Assignable anywhere in signal chain.
High- and Low-Pass Shelf Filter
- Adjustable corner frequency.
- Adjustable Q factor.
- Adjustable gain.
- Graphical response curve provided in software.
- Ability to bypass all EQ with a single mouse click.
- Ability to add or delete EQ.
- Assignable anywhere in signal chain.
Output Peak Limiter
- Adjustable threshold.
- Adjustable attack time.
- Adjustable release time.
- Graphical response curve provided in software.
- Ability to quickly bypass limiter with a single mouse click.
- Assignable anywhere in signal chain.
Multiple Delays
- 910 millisecond maximum (sum of all delay objects).
- 20.83 microsecond increments.
- Entry can be in seconds, feet, or meters.
- Assignable anywhere in signal chain.
Parametric EQ
- Adjustable frequency.
- Adjustable gain.
- Adjustable Q factor.
- Ability to bypass all EQ with a single mouse click.
- Ability to add or delete EQ.
- Graphical response curve provided in software.
- Assignable anywhere in the signal chain.
Signal Compressor
- Adjustable attack and release times.
- Adjustable Gain.
- Adjustable threshold.
- Adjustable compression ratio.
- Graphical response curve provided in software.
- Assignable anywhere in the signal chain.
Signal Level Meter
Peak or RMS response.
Signal Attenuation
(Mute or bypass).
Mix Post Crossover Audio
(2 to 1 mixer with mute and lock all channels featured).
Signal Splitter
External Contact Closure Sensing
(pin #9 of RS-232, operates with "Switched Gain" objects in Signal Manager software).
Pink & White Noise Generator
Variable Frequency Tone Generator
Clip & Protect Indication
Signal Polarity Reversal
Section 1: Introduction - Block Diagram
Diagram Description: The block diagram illustrates the DSP-3's internal architecture. Key components include SRAM, FLASH, CODEC, DSP, Data Acquisition ADC, Micro-Controller, and RS-232/RS-485. Arrows indicate data flow: Analog Audio In/Out connect to CODEC. Vmon and Imon (for both channels) connect to the Data Acquisition ADC. The Micro-Controller interfaces with RS-232/RS-485.
Section 1: Introduction - Technical Overview
This section provides technical details of the DSP-3.
Audio Input Path
Features two audio channels, each with a balanced 3-pin 'euro' terminal block jack and an electronically balanced DataPort input. Inputs are protected against radio frequency interference and offer software-selectable full-scale input level sensitivity. The DataPort is scaled to clip with a full-scale digital input if the DSP-3's gain structure is unchanged. Each CODEC input is diode-protected.
Audio Output Path
The signal passes through an inverting gain stage, followed by a second-order Butterworth low-pass filter to remove high-frequency artifacts. Output is via the DataPort or 'Euro' connectors, with selectable output level.
Power Supply
No external power supply is needed for CX, DCA, and PL2 two-channel, 2 RU amplifiers manufactured August 1999 or later. These models supply power via the DataPort. CX, DCA, and PL2 amps made before August 1999, and all Powerlight amplifiers (non-'2' series), require an external DC supply. Amplifiers requiring external power may have serial numbers PRIOR to 0899XXXXX (MMYY datecode). External power is also required for remote mounting with Powerlight series (3 RU & 4-channel amps) and for all non-QSC amplifiers.
External power is supplied via a coaxial power cord jack on the DSP-3. Recommendation: When using an external power source, power up the DSP-3 before the amplifier to ensure trouble-free startup and avoid "thumps & bumps".
Data Acquisition
The DSP-3 samples IMON and VMON lines from QSC amplifiers via the DataPort for dynamics processing (limiter, compressor). Four channels of ADC continuously sample these inputs. For non-QSC amplifiers or those without a DataPort, the power limiter DSP "object" is unavailable, and amplifier protect/power status monitoring is not possible.
Contact Closure
A single contact closure input is provided on pin 9 of the RS-232 connector. Shorting this pin to ground (max 1.3 kOhms impedance) pulls a general purpose I/O pin low. This input is used by Signal Manager software to enable "Switched Gain" functions, allowing two gain settings per block (one for open, one for closed switch).
Section 2: Installation
Unpacking and Mounting
Unpacking: Keep original packing material for potential service needs. Ensure adequate protection for shipment if original material is unavailable.
What is Included in the Carton:
| Item | Description | Quantity |
|---|---|---|
| 1- | DSP-3 Digital Signal Processor | 1 |
| 2- | 3-pin terminal block connector plug | 4 |
| 3- | #4-40 machine screw, 1.125" long | 2 |
| 4- | #8-32 machine screw, 0.312" long | 1 |
| 5- | Hardware Manual (this document) | 1 |
| 6- | Signal Manager Software CD disk | 1 |
Direct Mounting the DSP-3 to 2-Channel, 2 RU QSC DataPort Equipped Amplifiers (CX, DCA, Powerlight2)
The DSP-3 mounts directly to the rear of these amplifiers.
- Configure amplifier DIP switches: All filters off, Clip limiter off, Mode set as required.
- Align the DSP-3's DataPort plug with the amplifier's DataPort jack and gently push to seat the connector.
- Install two #4-40 screws to secure the left side of the DSP-3 to the amplifier, threading into the DataPort jack inserts. Use a #1 Phillips driver and do not overtighten.
- Install the #8-32 screw to secure the right side of the DSP-3 to the amplifier.
Warning: Ensure all three mounting screws are used. Twisting the DSP-3 without proper support can damage the "backside" DataPort connector.
Remote mounting (4-ch., Powerlight & non QSC amp's)
Remote mounting is required for 4-channel CX and DCA, Powerlight series, and all non-QSC amplifiers. Note that some dynamic processing capabilities may be unavailable with non-DataPort amplifiers.
Accessory Remote Mounting Bracket: This is a 19", 2-RU panel designed to hold up to four DSP-3 modules, mounting to equipment rack rear-support rails. It includes one large bracket and four smaller right-angle brackets for flexible mounting.
Mounting Steps:
- Attach a right-angle bracket to the DSP-3 module.
- Attach the DSP-3 and right-angle bracket assembly to the main 19" bracket.
- Mount the main bracket assembly in your equipment rack between the rear support rails.
- Connect inputs, outputs, DataPorts, RS-232, and external power as required.
Connections
Connecting Audio Inputs and Outputs
The DSP-3 uses 3-pin "Phoenix"-type (Euro-style) terminal block connectors for audio inputs and outputs, allowing pre-wiring without soldering. See Appendix for connector part numbers.
Inputs
Inputs can be from the front-panel DataPort OR the terminal-block INPUT connectors. Do not use both sets of inputs simultaneously. Balanced connections are recommended for lowest noise and to minimize ground loops.
Outputs
Post-DSP audio is output via the rear-panel DataPort AND the terminal-block OUTPUT connectors. The OUTPUTs can be used for daisy-chaining processed audio to additional amplifiers.
Balanced vs. Unbalanced Connections
Balanced connection is recommended for all inputs. The terminal block inputs are electronically balanced. Connect the positive (+) signal wire to the left-most terminal.
Unbalanced inputs can be used if necessary. If using unbalanced sources, an audio transformer or converter is preferable to provide a balanced input. If not possible, connect the negative terminal and shield terminal together with a jumper wire.
Terminal Block Wiring
To connect signal wire: Loosen the screw on the terminal block, insert the conductor into the proper location, and retighten the screw. Recommended wire stripping length is 6-8 mm (1/4 to 5/16 inch). Avoid nicking conductor strands. Twist stranded wire ends together to prevent shorts.
DataPort Connection
This section applies to users interfacing with QSC DataPort products. If using the DataPort for audio inputs, do not use terminal block inputs. If DataPort is used only for control/monitoring, audio inputs can use terminal blocks.
The front-panel DataPort connects to QSC DataPort products using a QSC DataPort cable (male-to-male), similar to VGA cables but specifically constructed for the DSP-3. Obtain these cables from QSC distributors or Technical Services.
The rear-panel DataPort connects the DSP-3 to QSC amplifiers when mounted directly. For other accessories, orient the connector properly, insert fully, and finger-tighten retaining screws. Rear-panel DataPort signals are post-DSP.
Front panel DataPort connection is not required for DSP-3 operation.
Diagram Description: The DataPort Connection diagram shows a 15-pin cable connecting to the DSP-3's DataPort.
RS-232 PORT Connection
Connection is made using a 9-pin serial data cable (male-to-female), with a recommended maximum length of 25 feet. Orient the DB-9 plug correctly and insert fully.
The RS-232 port is used for DSP-3 setup and programming. "Real-time" control requires the connection to be maintained; otherwise, the DSP-3 can be set up and disconnected. The RS-232 connection is not required for basic DSP-3 operation.
Setup and programming can also be done via Ethernet network communication using QSC's QSControl products (refer to QSControl documentation).
Diagram Description: The RS-232 Connection diagram shows a 9-pin cable connecting to the DSP-3's RS-232 port.
Daisy-Chaining the DSP-3 Outputs to Additional Amplifiers
The DSP-3 provides audio output jacks for each channel, usable for daisy-chaining post-DSP signals to other amplifiers or for monitoring. Terminal block outputs are active even when DataPort connections are used. Connect DSP-3 output jacks to the input jacks of the next amplifier, ensuring balanced and properly connected cables.
Connection to Accessory External DC Power Source
An external DC power supply is required when the DSP-3 is used with QSC Powerlight amplifiers that do not provide +15VDC via DataPort, or with non-DataPort amplifiers. QSC offers an accessory power supply; third-party supplies may work if voltage, type (DC), current rating, and polarity are correct. Damage from non-QSC supplies is not covered under warranty.
Warning: Ensure the external power supply is of the proper voltage type, level, and current rating. Verify connector polarity, as there is no industry standard. Incorrect voltage can cause immediate damage.
Insert the coaxial power plug firmly into the EXTERNAL POWER jack. Use the chassis "tab" to secure the power cord with a tie-wrap.
Diagram Description: The external power supply diagram shows a wall adapter with a barrel connector.
Application Examples
The following examples illustrate basic hookups for a two-channel, full-range audio signal. Refer to amplifier manuals for other configurations.
DSP-3 Directly Mounted to QSC Amplifier. Audio Inputs via Terminal Block Inputs
Application: DSP-3 and QSC DataPort equipped amplifier supporting direct mounting. Audio inputs via terminal block connectors. Note: PC connection is only required for initial setup. ISA amplifiers require the external accessory power supply as they do not provide accessory power.
DSP-3 Directly Mounted to QSC Amplifier. Networked OR Local Control. Audio Inputs via DataPort.
Application: DSP-3 and QSC DataPort equipped amplifier supporting direct mounting. Audio inputs via CM16a DataPort connection. Note: PC connection only required for initial setup. ISA amplifiers require the external accessory power supply.
Note: External accessory power supply may be required on older models; see page 2 for details.
DSP-3 Remotely Mounted used with QSC DataPort Amplifier. Audio Input via Terminal Block Inputs
Application: DSP-3 and QSC DataPort equipped amplifier requiring remote mounting. Audio inputs via QSC CM16a Amplifier Network Monitor. Note: Accessory DC power supply required for Powerlight amplifiers. PC connection only required for initial setup.
DSP-3 Directly Mounted to QSC Amplifiers, Networked Control via QSCcontrol Products
Application: Networked control of DSP-3 and remote monitoring/control of QSC DataPort equipped amplifiers using CM16a Amplifier Network Monitor. Note: Up to eight 2-channel amplifiers may be connected to a CM16a. External accessory power supply may be required on older models.
DSP-3 Remotely Mounted connected to any Non-DataPort Amplifier. Audio Input via Terminal Block Inputs
Application: DSP-3 and any amplifier without a DataPort connector. Terminal block connectors are used for inputs and outputs. Power limiting and amplifier power/protect status monitoring are not supported. DataPort connections on the DSP-3 are unused. Note: Accessory DC power supply required. PC connection only required for initial setup.
Section 3: Signal Manager Software - Software Installation
System Requirements
To use QSC Signal Manager, the following are required:
- IBM compatible computer, 200 MHz or greater Pentium Processor.
- Windows 98/2000 or Windows NT 4.0 with service pack 6a or later.
- SVGA display (800x600 minimum, 1024x768 recommended).
- CD-ROM drive.
- 32 MB or more of RAM.
- 10 MB of free hard disk space.
- Available RS-232 serial communications port (COM port) capable of 38.4k baud.
- A male-to-female 9-pin serial cable.
Software Installation
- Insert the QSC DSP-3 Signal Manager CD into your CD drive. If AUTORUN is enabled, installation starts automatically. Otherwise, proceed to step 2.
- Run D:\Setup.exe (replace D: with your drive letter) and follow instructions.
- Upon completion, review the "Readme" file for important up-to-date information.
- An icon labeled "Signal Manager" will appear on your desktop; double-click to start the application.
- Use the "Help" menu to access the software help section, which includes this manual for paperless reference. Visit qscaudio.com for DSP-3 updates.
- IMPORTANT! The DSP-3 ships with presets configured for full-range audio. This may not be appropriate for your setup. Configure necessary crossovers, filters, etc., prior to applying audio signals to prevent equipment damage.
Overall Notes and Warnings
- The last applied configuration running in the DSP-3 when powered off becomes active upon power-up, ensuring the system resumes its previous state.
- Do not operate amplifiers at maximum gain while making real-time DSP-3 adjustments. Communication path complexity can lead to unpredictable results or damage if the PC or channel fails. Use minimum useful gain settings during adjustments.
Section 3: Specifications
Signal Processing
24 bit, 48 kHz.
| Parameter | Specification | Notes |
|---|---|---|
| Frequency response (at 3dB below full scale input voltage) | 20 Hz–10 kHz ±0.3 dB (term. block inputs) 20 Hz–20 kHz ±0.7 dB (term. block inputs) 20 Hz–20 kHz±0.2 dB (DataPort inputs) | |
| Distortion | <0.01% THD+N @ +4 dBu out | |
| Delay (throughput) | 687.5 microseconds | |
| Dynamic range | >93 dB unweighted (20 Hz–20 kHz, 1.5V, 4V, 9V sensitivity) >88dB unweighted (20 Hz–20kHz, 18V sensitivity) | |
| Polarity | In-phase or inverted | |
| Mute | >90 dB attenuation | |
| Inputs | Program inputs: 2 Connector type: "Phoenix-style" (Euro-style) detachable terminal blocks Type: Electronically balanced Grounding: All shield terminals connected to chassis Input sensitivity (full scale input level): 1.5, 4.0, 9.0 or 13.0 Vrms; 6, 14.5, 21.5 or 24.5 dBu; 3.5, 12.0, 19.0 or 22.2 dBv (selectable in software) Impedance: 8.3 K Ohm balanced, 3.7 K Ohm unbalanced | |
| Common-mode rejection | >50 dB, 20 Hz–20 kHz | |
| Crosstalk | >75 dB separation, 20 Hz–20 kHz | |
| Outputs | Program outputs: 2 (via HD-15) Connector type: HD-15 DataPort connection Pinout: Special, see appendix Cable type: QSC DataPort cable Qualified length: 2 meters Daisy-chain output Connector: 2 (1 per channel), "Phoenix-style" (Euro-style) detachable terminal blocks Type: Electronically balanced Grounding: Shield terminal connected to chassis Output level (full scale): 6.0 or 4.0 Vrms; 18.0 or 14.5 dBu; 15.5 or 12.0 dBv Output impedance: 600 Ohms balanced |
Power amplifier connectivity
| Parameter | Specification | Notes |
|---|---|---|
| Compatibility | All QSC and non-QSC amplifiers | |
| Full-feature set | All QSC DataPort equipped amplifiers | |
| Connector and cable | HD-15 VGA cable, 2 meters length (qualified for longer runs, contact QSC Technical Services) | |
| Amplifiers | One 2-Ch. amplifier per DSP-3 | |
| Amplifier status monitor | Clip indicator: Senses channel clipping Protect indicator: Senses amplifier protect status | Status monitoring not available for non-DataPort amplifiers |
RS-232 Port
| Parameter | Specification | Notes |
|---|---|---|
| Cable Type | 9-pin serial cable, male-to-female | |
| Maximum Length | 25 feet (7.6 meters) |
Contact closure input (sense)
| Parameter | Specification | Notes |
|---|---|---|
| Inputs | 1 discrete input (pin #9 of RS-232 port) | |
| Configuration | Single-ended input | |
| Resistance for closure detect | <150 Ohms | |
| Resistance for open detect | >1.9 K Ohms | |
| TTL Compatible | ||
| Maximum Voltage | +9vdc |
Note: Specifications are subject to change without notice.
Section 4: Architect's and Engineer's Specifications
The Digital Signal Processor (DSP) shall provide two independent channels of DSP for signal delivery to QSC DataPort equipped power amplifiers. Processing shall be distributed with the DSP module mounted directly to the rear of the power amplifiers.
Output Peak Limiter
For each audio channel, the DSP shall provide a peak limiter assignable anywhere in the signal chain, with switchable on/off functionality. Adjustments include: Gain, Threshold, Attack time, Release time.
High- and Low-Pass Crossovers
For each audio channel, the DSP shall provide high-pass and low-pass crossovers assignable anywhere in the audio chain. Crossovers must be switchable in/out of the signal chain. Crossover responses: Butterworth (6,12,18,24 dB/octave slope), Bessel (6,12,18,24 dB/octave slope), Linkwitz-Riley (12 & 24 dB/octave slope).
High- and Low-Pass Shelf Filters
For each audio channel, the DSP shall provide high-pass and low-pass shelf filters assignable anywhere in the audio chain. Shelf filters must be switchable in/out of the signal chain. Adjustments include: Variable corner frequency, Variable gain, Variable slope.
Compressor
The DSP shall provide a signal compressor assignable anywhere in the signal chain, with adjustable threshold, attack time, release time, and compression ratio.
Contact Closure I/O
The DSP shall provide a trigger input compatible with CMOS & TTL signals for contact-closure or other purposes.
Power Supply
Power shall be supplied via the DataPort connection to QSC amplifiers. For older or non-QSC amplifiers, a coaxial power jack is provided for an external power source (+15 VDC at 300 mA max.).
Amplifier Interface
The DSP shall attach directly to the rear of each power amplifier via an HD-15 connector DataPort interface. This interface transmits two amplifier input audio signals and all control/monitoring signals. Special signal conditioning ensures negligible noise and crosstalk. For non-DataPort amplifiers, mounting and interface options are provided.
Amplifier Output Monitoring
When used with QSC DataPort amplifiers, the DSP shall detect clipping and protect status at the amplifier's output terminals.
Noise & Tone Generation
The DSP shall provide pink and white noise generation capability, as well as tone generation.
Presets
The DSP shall store at least 8 preset configurations, managed by the control software.
General
All audio inputs and outputs shall be balanced with a nominal input level of +4 dBu and maximum level of +21 dBu. Input connectors shall be "Phoenix" detachable terminal blocks.
Control
The DSP shall be configurable via RS-232 or a networked DataPort connection.
The Digital Signal Processor shall be the QSC DSP-3.
Section 5: Appendix
DataPort Pinout
The diagram shows pin assignments for the HD-15 connectors on the DSP-3 and amplifier.
Note: This information is for reference only and specific to QSC products.
| Pin | Signal Description |
|---|---|
| 1 | Ch. 1 Minus (-) Input Signal |
| 2 | AC Standby Control |
| 3 | V- MON Ch. 1 and Subcode 1 |
| 4 | I- MON Ch. 1 and Subcode 2 |
| 5 | Clip/Protect Ch. 1 |
| 6 | Hard Ground |
| 7 | Ch. 1 Plus (+) Input Signal |
| 8 | Ch. 2 Plus (+) Input Signal |
| 9 | +15V from Amplifier |
| 10 | Data Reference Ground |
| 11 | Ch. 2 Minus (-) Input Signal |
| 12 | Amplifier IDR (Model ID) |
| 13 | V- MON Ch. 2 and Subcode 3 |
| 14 | I- MON Ch. 2 and Subcode 4 |
| 15 | Clip/Protect Ch. 2 |
Note: Powerlight 6.0 and 9.0 amplifiers require pin #9 removed from the interconnect cable. Amplifier damage may result if pin #9 connections are present.
Description of Encode Signals
- encode 1: Bridge mode & power detect
- encode 2: Temperature, channel 1
- encode 3: Standby mode detect
- encode 4: Temperature, channel 2
RS-232 Port Pinout & Connector P-N's
The diagram shows pin assignments for the RS-232 connector on the DSP-3. Pin #9 is used for Contact Closure function.
| Pin | Signal Description |
|---|---|
| 1 | DCD |
| 2 | TD |
| 3 | RD |
| 4 | DTR |
| 5 | Signal GND |
| 6 | DSR |
| 7 | RTS |
| 8 | CTS |
| 9 | contact closure |
Terminal Block Connector Part Number Reference
3 pin without integral strain relief: Phoenix Contact - 17 57 02 2; Riacon - 31249103-6; On Shore Tech - EDZ950/3
3 pin WITH Strain Relief: Phoenix Contact 17 76 16 8
Trademarks: Phoenix Contact, Riacon, On-Shore Technology.
Application Information
As design improvements are continuous, this information is subject to change. Contact QSC for current details.
The DSP-3 attaches directly to the DataPort connector of QSC's CX, DCA, Powerlight, and Powerlight 2 series amplifiers. Amplifiers manufactured 08/99 and later receive power via the DataPort. Earlier models and all Powerlight amplifiers (non-'2' series) require an external DC supply from QSC.
Clarification: CX, DCA, and PL2 amps made prior to August 1999 do not provide adequate power supply voltage and require the same external DC supply used with Powerlight amplifiers. These amps have serial numbers PRIOR to 0899XXXXX (MMYY datecode).
Full feature set, Direct-mounting, No external power or special interconnect cables required:
For QSC power amplifiers with serial numbers of 0899XXXXX and later (MMYY datecode):
- CX series: CX302 - CX1202V (all)
- DCA series: DCA1222, DCA1622, DCA2422, DCA3022, DCA342
- PL2 series: PL224, PL230, PL236, PL218
- PL2A series: All
Remote Mounting Required, QSC DataPort Cable required: Full feature-set, no external power required.
- CX series: CX204V, CX254, CX404
- DCA series: DCA1644, DCA1824
Remote Mounting, QSC DataPort Cable and External Power required: Full feature-set.
- Powerlight series: PL1.0 through PL4.0 (all)
- Note: PL6.0 and PL9.0 require a modified DataPort cable between DSP-3 and amplifier. Pin #9 MUST be removed from the Amplifier-to-DSP DataPort Cable before use!
Remote Mounting and External Power required. No DataPort Connection possible, Power Limiting not available.
- ISA series: "V2" DataPort may be used for audio inputs only.
- MX series: All
- PLX series: All
- RMX series: All
- USA series: All
- ALL non-QSC amplifiers can be used with the DSP-3.
Preset Operation Notes
Special Information Concerning Saved DSP-3 Configurations: The computer used to create and save DSP-3 configurations should ideally be the same one used for future modifications. Save configurations to floppy disk for transferability.
The Reason: Signal Manager software creates DSP signal flow configurations (filters, delays, limiters) displayed as "configuration files" with graphical representations. Users create signal chains by "wiring" function blocks. When "Apply to DSP" is performed, compiled algorithm coefficients are downloaded, not the graphical representation.
When building a new configuration from scratch and applying it, you'll be prompted to save it as a Configuration file. This file path is associated with the loaded algorithms. Applying a previously saved file associates its path with the loaded algorithms.
Connecting a DSP-3 to a computer attempts to display the configuration file associated with the currently running algorithms to correlate "what you hear" with "what you see". If the file is not found (renamed, moved, deleted, or different computer), a message asks to load the Default configuration. Answering YES loads the Default configuration to the screen but does NOT apply it to the DSP-3. Answering NO displays a blank workspace. What is displayed may not reflect what is currently running in DSP-3 memory.
Warning: Performing "Apply to DSP" at this point will overwrite the current DSP-3 configuration! To avoid this, locate the desired configuration file using Configuration > Open (Ctrl-O). Once displayed, select Configuration > Edit (Ctrl-E), then Apply to DSP (Ctrl-D) to download the displayed configuration and synchronize it with the DSP-3's memory.
QSC engineers are working on improvements to always display the currently running configuration.
Section 6: Maintenance, Warranty & QSC Contact Information
Cleaning
Clean the faceplate and chassis with a soft cloth and mild, nonabrasive cleaning solution (e.g., Simple Green, Windex). Do not use powders or scrubbing pads, as they can damage the finish. Dampen a lint-free cloth with solution and wipe gently. Ensure no cleaning solution enters connectors. Do not spray directly onto the DSP-3.
User Maintenance
There is no user-level maintenance. Contact QSC's Technical Services Department for service.
Warranty Information
If the DSP-3 is not working properly, verify the 9-pin serial cable. If issues persist, service by qualified personnel may be required. Contact your QSC dealer or QSC's Technical Services Department to locate an authorized service center.
Disclaimer
QSC Audio Products, Inc. is not liable for damage to speakers, amplifiers, or other equipment caused by negligence, improper installation, or use of the DSP-3. Due to the complexity of communications, QSC is not liable for direct or indirect damage caused by computer communications failure.
Product Warranty
QSC guarantees products to be free from defective material and workmanship for three (3) years from the date of sale. Defective parts will be replaced, and malfunctioning products repaired under warranty when defects occur under normal installation and use. The unit must be returned to QSC factory or authorized service station pre-paid, with proof of purchase. Warranty covers manufacturing defects and does not extend to misuse, neglect, accident, improper installation, or defaced date codes. QSC is not liable for incidental or consequential damages. This warranty grants specific legal rights, which may vary by state. The limited warranty is transferable during its term.
Contact Information
WORLD WIDE WEB: http://www.qscaudio.com
TELEPHONE NUMBERS:
Main Number: (714) 754-6175
Sales Direct Line: (714) 957-7100 or (800) 854-4079 (U.S.A. only toll-free)
Technical Services: (714) 957-7150 or (800) 772-2834 (U.S.A. only toll-free)
FACSIMILE (FAX) NUMBERS:
Sales & Marketing FAX: (714) 754-6174
Technical Services FAX: (714) 754-6173
ADDRESS:
QSC Audio Products, Inc.
1675 MacArthur Boulevard
Costa Mesa, CA 92626-1468 USA
