DPR-901ii User's Manual This Manual is the COPYRIGHT of BSS Audio. All reproduction and copying, other than for the legal owner's personal use, or disclosure of part or whole to a third party, without prior written authorisation, is in violation of the European Copyright Convention.
DPR-901ii Welcome V1.1 9 August 1995 Welcome to the DPR-901ii Users Manual DPR-901ii ABOVE AND BELOW THRESHOLD DYNAMIC PARAMETRIC EQUALISATION. This manual is provided with the aim of assisting sound engineers, producers, musicians, system installers and consultants to fully understand the DPR-901ii, and to benefit from it’s maximum capability. As opposed to most manuals, the contents can be read like a book. At the same time, the information is structured under a series of broad headings for easy access.
Table Of Contents Table Of Contents 1.0 1.1 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 Introduction 4 Features and Facilities 5 Installation 6 Unpacking Mechanical Installation Mains Power Voltage Setting Safety Earthing AC Power Fusing Audio Connections Ground Loop Control 6 6 7 8 8 8 9 10 3.0 Controls 11 4.0 Principle of operation 16 5.0 Using the DPR-901ii 18 6.
DPR-901ii Introduction 1.0 Introduction Congratulations!. Whether you’re a sound engineer, producer, consultant, installer or musician, you’ve just added a powerful new weapon to your audio armoury. The DPR-901ii is a new class of audio equaliser. Both subtle and powerful, it builds on the established problem solving capabilities of parametric equalisers. It’s uses range from processing and sweetening speech, instruments and composite music, through SPL control, to loudspeaker system and room tuning.
Features and Facilities 1.1 Features and Facilities The DPR-901ii is a four band parametric equaliser which varies the degree of equalisation dynamically, as the program level changes. The process can be thought of as frequency selective compression and/or expansion, but it is fundamentally different to simple ‘frequency-conscious’ dynamics processing as used for noise gating, de-essing and the like.
DPR-901ii Installation Unpacking Mechanical Installation 2.0 Installation 2.1 Unpacking As part of BSS AUDIO’s system of quality control, this product is carefully checked before packing, to ensure flawless appearance. After unpacking the unit, please inspect for any physical damage and retain the shipping carton and all relevant packing materials for use should the unit need returning. A packet of spare fuses is supplied. Please keep them in a safe place.
Mains Power The internal power supply regulators are mounted on the case sides and use this as their heatsink. After a period of time in an enclosure, the metal case will feel hot to the touch, but this is quite normal and should not be a cause for alarm. 2.3 Mains Power Before connecting your unit to its AC power source, check that the voltage selector switch located on the rear panel is correctly set. See figure 2.2. WARNING: THIS APPLIANCE MUST BE EARTHED.
DPR-901ii Voltage Setting Safety Earthing AC Power Fusing 2.4 Voltage Setting The mains voltage selector switch provides a simple external adjustment to allow operation on all international AC power standards. The allowable ranges for the supply voltage are: 96VAC up to 132VAC on the 115V position and 195VAC up to 264VAC on the 230V position. An additional internal tap change is available for 100V working. Refer to Appendix A.2.
Audio Connections 2.7 Audio Connections The DPR-901ii audio inputs are RFI filtered and electronically balanced, with the outputs electronically balanced and floating. They are designed to operate at any signal level up to +20dBu and will drive into loads of 600 ohms or greater. They will be ‘fuss free’, regardless of your installation’s complexity. Figure 2.3 shows the connector wiring.
DPR-901ii Ground Loop Control 2.8 Ground Loop Control Strict adherence to the wiring conventions noted above within a fully balanced signal system will yield the best possible results with none of the problems normally associated with interconnected audio equipment. Wherever possible, cable screens should not be connected to any signal pin, but rather left to perform a cable shielding function only.
Controls 3.0 4 3 Controls 9 11 6 15 10 12 8 13 7 5 2 14 1 1 EQ IN When depressed, the processing is engaged and the LED (underneath) lights in confirmation. When released, processing is disabled; the LED is off and the incoming signal passes to the output unchanged and at unity gain (0dB). Note: As the DPR-901ii’s entire signal path is bypassed in this mode, signal will be passed to the output even if the AC power is disconnected - or fails.
DPR-901ii Controls 4 3 9 11 6 15 10 12 8 13 7 5 2 14 1 5 IN When depressed, the band is operative. The LED underneath lights. When released, the band is bypassed. This is useful for dropping out effects when they’re not needed (without disturbing the other settings), and for A/B comparisons. 6 FREQUENCY Turn to set the centre frequency of the dynamic activity.
Controls 9 FILTER/DEFEAT (Band two and band three only). Switches the EQ from a bell response to a flat (wide-band) response. With the bell response, the process sensitivity is reduced symmetrically either side of the selected centre frequency. When the Defeat setting is selected by depressing the button, the affected band becomes EQ-less, like a conventional compressor/expander: it responds to all frequencies equally.
DPR-901ii Controls 4 3 9 11 6 15 10 12 8 13 7 5 2 14 1 11 Compression/ These horizontal LED displays give an instant, intuitive check on Expansion Display whether the process in each band is active, by how much, and whether it’s expansion or compression. The amount of expansion or compression is indicated by an easy-to-memorise 1-8 scale, with ‘8’ indicating maximum (hard) compress or expand.
Controls 14 BELOW Threshold When the switch is released, the processing operates above threshold, that is with compression or expansion being applied only to signal levels that exceed the threshold. When the switch is depressed to select Below, the green led beneath the switch lights. The threshold’s sensitivity setting remains the same, but the processing is ‘turned on its head’ as compression or expansion is now only applied to signals which are below the threshold.
DPR-901ii Principle of Operation 4.0 Principle of Operation The DPR-901ii is fundamentally different to ordinary de-essers, Dolby systems and the like because it uses subtractive techniques to control the degree of compression or expansion. This enables the VCA (gain control element) to be kept out of the direct signal path. As a result, the throughgoing signal is not subjected to the noise and distortion that’s intrinsic to even the best VCAs.
Principle of Operation expand level control, whose function is similar to a ratio control on conventional dynamic processors. The DPR-901ii Dynamic Equaliser, with four separate sections of this processing, offers considerable processing performance by adding another variable dimension to conventional equalisation.
DPR-901ii Using the DPR-901ii 5.0 Using the DPR-901ii Refer to the block diagram in Fig 5.1opposite. We recommend you familiarise yourself with the normal above threshold mode of operation before exercising the below threshold configuration. The latter is more subtle in effect, and requires more precise adjustments of level, especially in expansion. For high sound quality it’s important that you set the input drive correctly, particularly when using the expansion mode.
Using the DPR-901ii 5.
DPR-901ii Warranty Information 6.0 Warranty Information This unit is warranted by BSS Audio to the original end user purchaser against defects in workmanship and the materials used in its manufacture for a period of one year from the date of shipment to the end user. Faults arising from misuse, unauthorised modifications or accidents are not covered under this warranty. No other warranty is expressed or implied.
Chassis/0V Link Removal Appendix A A1 Chassis/0V Link Removal. NOTE: Since both the audio inputs and outputs are wired fully balanced we would suggest that you fully recheck all audio wiring for correctness prior to proceeding. All DPR-901ii units are shipped with the signal 0v/ground connected to the metal chassis via a wire link, and an rf bypass capacitor on the main pcb. The chassis is also dirctly connected to the (mains) safety ground/ Earth.
DPR-901ii Input pin 1 to Chassis Connection Transient Suppressor Replacement A2 Input pin 1 to Chassis Connection There are several options available on the connection between the input XLR pin 1, and the chassis, and the optimum configuration will depend upon the installation, and the equipment it is connected to. For the main input, positions LK1 and C1 are provided. The factory default is LK1 not fitted, and C1 is 100pF. For the split input, positions LK6 and C52 are provided.
Specifications Appendix B Input Section Output Section Specifications 12kohm electronically balanced, +20dBu (+20dBv) maximum input level via a 3 pin male XLR cable plug. Common Mode rejection > -50dB, 20Hz to 20kHz. Electronically balanced and floating, capable of driving +20dBu (+20dBv) into 600ohms or greater via an XLR female cable plug.
DPR-901ii Specifications Rear Panel Functions and Facilities General Main input Main output Split input Split output Power Size Weight 24 AC 40VA, 50/60Hz, 115v/230V selectable externally. IEC mains input socket 482mm x 44mm x 292.1mm (19" x 1.75" [1U] x 11.5" ) overall. 5kg gross shipping.
Glossary Appendix C Glossary ACTIVE Active electronic circuits are those capable of voltage and power gain by using transistors and integrated circuits. Passive circuits are those which use only resistors, capacitors, transformers, etc. BALANCED Refers to a 3-wire connection in which two of the wires carry the signal, and the third acts as a shield, tied to chassis ground. The two signal lines are of opposite polarity at any instant, but are at the same (numeric) voltage with respect to ground.
DPR-901ii describe voltage levels, although strictly it only applies to 600 ohm circuits. We recommend you use dBu instead. dBu or dBv The addition of ‘u’ or ‘v’ after dB indicates an absolute scaling for the dB ratio. 0dBu (or 0dBv) = 778mV or 0.778 volts, and it has no regard to power or impedance. dBu and dBv are widely used for expressing signal voltages in modern audio equipment, where output impedances are low, and input (load) impedances are much higher.
LIMIT Limiting occurs when a compressor having a high ratio, generally 6:1 or more passes a signal that exceeds the equipment’s threshold setting. Large variations in peak signal level are ‘squashed’, typically fluctuating less than 3dB for a 20 to 30dB increase. See EXPAND’ (above)for an explanation of compression and thresholds. LINE LEVEL Generally indicates signals between -10 and +10dBu, or -12 to +8dBV. Mic level refers to levels around -40dBu. Speaker levels are typically +10 to +40dBu.
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