DPR 404 User Manual 1
V3.0 JMK 26 July 1999 This equipment has been tested and found to comply with the following European Standards for Electromagnetic Compatibility: Emission Specification: EN55013 (1990) (Associated equipment) Immunity Specification: EN50082/1 (1992) (RF Immunity, Fast Transients and ESD) Mains Disturbance: EN61000/3/2 (1995) For continued compliance ensure that all input and output cables are wired with cable screen connected to Pin 1 of the XLR.
Contents Contents 1.0 The BSS DPR-404 5 2.0 Unpacking 6 3.0 Mechanical Installation 6 4.0 Earthing Requirements 7 5.0 Mains Power Connection 8 7.0 Audio connections 7.1 7.2 7.3 7.4 8.0 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9 8.10 8.11 9.0 9.1 9.2 9.3 9.4 9.5 9.6 10.0 10.1 10.
Contents 11.0 11.1 11.2 11.3 Compression Attack, Release and Ratio De-essing 20 20 21 22 12.0 Specifications 23 13.0 Service Section 25 13.1 13.2 14.
The DPR-404 1.0 The BSS DPR-404 The DPR-404 is a compact and professional four channel compressor and deesser. Based on the well established BSS subtractive gain reduction principle, it offers you four independent channels of high quality, musical compression and high frequency de-essing, with the minimum of operator controls. Designed to be quick and easy to operate by both skilled and novice engineers alike, it makes a compact economical alternative to the fully featured DPR-402 model.
Unpacking Mechanical Installation 2.0 Unpacking As part of BSS’ 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.
Earthing Requirements 4.0 Earthing Requirements WARNING! THIS APPLIANCE MUST BE EARTHED. IMPORTANT: The wires in the mains lead are colour coded in accordance with the following code. Green and Yellow......Earth Blue......Neutral Brown......Live As the colours of the wires in the mains lead may not correspond with the markings identifying the terminals in your plug, proceed as follows.
Mains Power connection 5.0 Mains Power Connection Voltage: The DPR-404 operates on either 120 or 240 volt supplies. Use the voltage selector switch to choose the required voltage setting. (See Figure 8.1). Frequency: Both 60Hz and 50Hz are acceptable. Fig 5.1 Mains fuse on rear panel. Grounding: The DPR-404 must always be connected to a 3-wire grounded ('earthed') AC outlet. The rack framework is assumed to be connected to the same grounding circuit.
Power ON: This is indicated the green 'ON' LED located under the CH 'IN' switches. If this LED is not lit when power is connected and the 'POWER' switch is depressed, see section 16.
Getting to know the DPR-404 Fig 6.1 Front Panel Fig 6.
All numbers in bubbles refer to Section numbers.
Audio connections 7.0 Audio connections The DPR-404 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. Note that pin 1 of the input XLR is not connected to ground. 7.
7.4 Linked operation For stereo program processing, channels 1 and 2 can be linked together by selecting the LINK switch on channel 2. Channel 1 will assume the master role, such that threshold, ratio, attack and release for channel two are equal to and controlled by channel 1 with the side chain controlling signal being the mono sum of both channels. This facility is also repeated for the second pair, channels 3 and 4. HF de-essing is similarly treated, when using the LINK mode.
Controls 8.0 Controls 8.1 IN When depressed the processing is engaged and the green LED 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. 8.2 Gain Output level control used to restore signal after processing, providing ÿ 20dB of adjustment range.
8.4 Attack/Release With the switches released, the function is automatically set and is program related, such that it follows the signal requirements for general vocal and mix program signals. (It closely follows the ‘auto’ mode on the DPR-402 unit). When depressed, the function is again automatically set and program related but is scaled to suit more transient program material such as percussion. 8.
8.7 De-ess 8.8 FREQ 8.9 Link 8.10 Link master LED 16 Threshold control for the high frequency de-esser circuitry. It works independently of the main compressor section and can be used simultaneously with it. It uses a second subtractive element that works to reduce only those high frequencies set by the FREQ control, leaving the other frequency content of the program unprocessed.
Rear panel controls 8.11 Main power fuse 9.0 20mm, T160mA for 240v AC voltage setting and T250mA for 120v AC voltage setting Rear panel controls 9.1 Mains voltage selector switch 9.2 Mains power switch 9.3 Mains voltage selector switch Allows operation from 90v-130v or 190v-250v 50/60Hz AC mains voltage. Turns the unit on/off. Allows operation from 90V-130V or 190V-250V 50/60Hz AC mains voltage.
Rear panel controls 9.4 External side chain insert 9.5 Electronically balanced input Offers a line level insertion point, on an RTS jack, into the control side chain. Connections are: Ring: Signal output from 470 source. Tip: Return input to 10k. Sleeve: 0v ground. Maximum input is +20dBu into 10kohms. The pin connections are: Pin 1: Open circuit/no connection. Pin 2: Hot (+). Pin 3: Cold (-). Note: Transformer balancing is available as an option. 9.
Compressors and Limiters 10.0 Compressors and Limiters 10.1 The need for Gain Control The human ear excels in its ability to detect an extremely wide range of sound levels. These can range from the quietest whisper to the roar of a jet aircraft. When we attempt to reproduce this large range (dynamic range) of sounds with amplifiers, tape recorders or radio transmitters, we run into one of the fundamental limitations of electronic or acoustic equipment.
Compressors and Limiters Fig 10.2 Operating level and Headroom It therefore becomes apparent that to get the most out of an audio system, the standard operating level must be kept as high as possible without risking distortion. One solution to this problem is for the operator of the equipment to be continuously monitoring the program, and manually adjusting the gain to suit the moment. When the program is quiet, the gain can be increased, and when the program is loud the gain can be reduced.
In the DPR-404, gain reduction is achieved by using a proprietary subtractive circuit which minimises signal degradation and has a maximum attenuating range of 30dB. The THRESHOLD control is used to position the input program signal into the window of operating range for the circuit. Rotating the control anticlockwise from the ‘out’ position will bring the signal onto the BELOW TH meter.
The effect of Compression 11.0 The effect of Compression on sound 11.1 Compression Consider an input signal which is applied to two units, one having its threshold point set 10dB higher than the other. Since the compressor only affects signals that exceed the threshold level, the signal with the lower threshold applied will be more affected than the other. Referring to figures Fig 11.1a High threshold level Fig 11.1b Lower threshold level 2.
Comparing the input and output waveforms for the compressed mode, the loudest portions of the signal have been effectively decreased in level, and if the gain control is adjusted to compensate for this, the quieter portions will be increased. The net effect, therefore, is for both ends of the dynamic spectrum to be pushed (or squeezed) towards each other. This squeezing effect of compression is important to remember, and provides a major difference between compression and limiting. I.e.
De-essing and Peak Limiter 11.3 De-essing A common problem encountered when amplifying or recording the human voice is the large amount of high frequency energy heard as the sibilant (Sss) sound. These sounds can reach levels considerably greater than the normal voice level, and can result in signal break-up or distortion. It is possible to control these sounds by using a compressor which is specially configured to respond to, and only reduce, these high frequencies.
Specifications 12.0 Specifications Input section 12k ohm electronically balanced, +20dBu (+20dBv) maximum input level via a 3 pin male XLR cable plug. Common Mode rejection: > -50dB, 20Hz to 20kHz Input section Electronically balanced and floating, capable of driving +20dBu (+20dBv) into 600 ohms or greater via an XLR female cable plug. Frequency response: +/- 0.
Specifications Side chain insert: Rear panel RTS jack accesses side chain for inserting other equipment at line level. Connections are: Ring: Signal output from 470 ohms source Tip: Return input into 10kohms Sleeve: 0v ground Power: AC 50/60Hz 120v/240v switched externally giving operation range of 90-132v and 180-264v. Anchored 2m power cord Size: 482 x 44 x 282mm 19” x 1U x 11.10" Weight: 4.1kg gross shipping Options Transformer balancing for input and output.
!!! CAUTION - Important Notes !!! SERVICE SECTION 13.0 Service Section 13.1 Transient suppressor replacement The primary of the input transformer is protected against high voltage spike interference by two voltage dependent resistors (VDR). These provide a momentary short circuit to voltage peaks in excess of the normal power voltage rating.
!!! CAUTION - Important Notes !!! SERVICE SECTION 13.2 Separating signal and chassis ground In some installations, it might be necessary to separate the electronic signal 0V ground from the chassis ground to avoid earth loops. Since both the inputs and outputs of the DPR 504 are balanced, correct connector wiring should be alleviate this problem. Prior to continuing with this procedure, it is recommended that you recheck all audio wiring for correctness.
Warranty Information 14.0 Warranty Information When sold to an end user by BSS Audio or a BSS Audio Authorised Reseller, this unit is warranted by the seller to the purchaser against defects in workmanship and the materials used in its manufacture for a period of one year from the date of sale. Faults arising from misuse, unauthorised modifications or accidents are not covered under this warranty. No other warranty is expressed or implied.
Index Index A Attack Time 21 B Below Threshold. See Compression meters; Compression meters: Below Threshold C Chassis ground separating from signal Compression 26 20 D Dynamic Range 17 E Earthing 7 F Front Panel Fuses. See Mains Connection 10 G Gain Reduction. See Compression meters: Gain Reduction Getting to know the DPR-402 10 Grounding. See Grounding H Headroom 18 I Installation 6 M Mains Connection 8 Meter Input. See Compression meters: Meter Input O Output Level.
Index Release time 21 S Specifications 23 T Threshold Transient suppressor replacement 14 25 U Unpacking 6 W Warranty Info.
User Notes 32
User Notes 33
