DPR 422 User Manual 1
V 1.
Contents Contents 1.0 Mechanical installation 5 2.0 Mains Power Connection Mains Power 6 6 3.0 Introduction 7 4.0 Unpacking 7 5.0 5.1 5.2 5.3 5.4 Audio Connections Main Inputs Main Outputs Side Chain Inputs Side Chain Outputs 10 10 10 11 12 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 6.10 6.11 6.12 6.13 Control Operations Operating Level Threshold Ratio Attack Release AUTO Stereo Link Gain Channel In De-ess Frequency De-ess HF Side Chain Listen 13 13 13 14 15 15 16 16 17 17 18 18 18 19 7.1 7.2 7.
Contents 8.0 General Applications The need for Gain control Compressors and Limiters The effect of Compression and Limiting on sound De-essing Broadband De-essing HF De-essing 22 22 23 Operation and applications Compression De-essing HF De-essing HF De-essing with full Dynamic control Peak Limiting Side chain insert 26 26 26 27 10.0 Troubleshooting 29 11.0 Warranty Information 30 12.0 Specifications 31 13.0 Glossary 32 Index 34 User Notes 36 8.1 8.2 8.3 8.4 8.5 8.6 9.0 9.1 9.2 9.3 9.
Mechanical Installation 1.0 Mechanical installation A vertical rack space of 1U (1¾" / 44.5 mm high) is required, with a depth of 190mm. Ventilation gaps are unnecessary (See Figure 1.1). If the unit is likely to undergo extreme vibration through extensive road trucking and touring, it is advisable to support the unit at the rear and/or sides to lessen the stress on the front mounting flange.
Mains Power Connection 2.0 Mains Power Connection 2.1 Mains Power WARNING! THIS APPLIANCE MUST BE EARTHED. The DPR-422 must always be connected to a 3-wire earthed AC outlet. The rack framework must also be connected to the same grounding circuit. The unit must NOT be operated unless the power cables' EARTH (ground) wire is properly terminated - this is important for personal safety as well as for proper control over the system grounding.
Introduction Unpacking 3.0 Introduction The BSS DPR-422 compressor, de-esser has been designed in response to the demand for a versatile, cost effective two channel unit which maintains the proprietary, audibly transparent, subtractive VCA technology as used in the well established BSS DPR-402 unit. The provision of a separate, balanced insert input and output per channel minimises the possibility of interference that other units with unbalanced connections may suffer from.
The DPR-422 Fig 4.1 Front Panel Fig 4.
All numbers in bubbles refer to Section numbers.
Audio Connections 5.0 Audio Connections 5.1 Main Inputs There are 2 input sockets on the rear panel of the 422, Inputs 1 and 2. Each is electronically balanced on standard 3 pin female XLRs at an impedance greater than 10k Ohms. The ‘HOT, + or in phase’ connection is to pin 2 and the ‘COLD, -, or out of phase’ connection is to pin 3. Pin 1 is internally connected to the chassis earth via a low value capacitor. This ensures freedom from ground loops whilst allowing good EMC performance.
When using the DPR-422 to drive unbalanced inputs, best performance is usually obtained by connecting the DPR-422s ‘+’ signal to the equipment signal pin and the ‘-’ signal to the equipment shield. Fig 5.4 The DPR-422 shield should normally be connected to the equipment shield, preferably at the equipment end. Transformer isolated outputs are also available as a dealer fitted option. 5.
Audio Connections 5.4 Side Chain Outputs The side chain uses a quasi-balanced ‘ground compensated’ output. When connected to a balanced input, interference rejection equivalent to a fully floating output can be obtained. Full headroom is available into any load of 2k Ohms or greater. The signal ‘HOT, +, or in phase’ signal is to the jack plug tip. The ‘COLD, -, or out of phase’ signal is to the ring with the shield being connected directly to the chassis. Fig 5.
Control Operations 6.0 Control Operations 6.1 Operating Level Setting this switch on the rear panel to +4dBu configures the DPR-422 for connection in a professional system. The THRESHOLD control and OUTPUT METER will read in dB relative to 0dBu, and the side chain insert points will be set for connection to professional signal level equipment. With the switch set to -10dBV, the DPR-422 shifts its internal operating point to make it more suitable for connection to semi-professional equipment.
Control Operations When the THRESHOLD control is set fully clockwise to the position marked OUT the threshold can not be reached, regardless of the input level, and the signal will always reach the output uncompressed. How the compressor performs on signals above the threshold is controlled by the RATIO, ATTACK, and RELEASE controls (see the following sections for more info.) 6.3 Ratio The effect of the ratio control can be shown on a graph which plots input level against output level (see figure 6.1).
6.4 Attack This control determines how quickly the DPR-422 compressor responds to signals once the threshold is exceeded and provides a range of times from 50us to 100ms. For transient signals (very sudden 'spikes' in the signal that last a short time), a fast attack time is desirable. For other types of program material a slower time will be more useful.
Control Operations If set too fast, the overall volume level will jump up and down, exactly following the peaks above threshold, producing an unpleasant effect. If set too low, quiet parts of the program immediately following loud transients will be subjected to ‘breathing’ or ‘pumping’ effects caused by the VCA releasing its attenuation (or effectively increasing the system gain) during the quiet program period, when it is not required. 6.
When linked, the channel 1 below threshold meter shows the combined channel 1 & 2 signal. The channel 2 below threshold meter shows only signals on channel 2, this provides a visual indication that there is a signal on channel 2. Note that the level on the channel 2 meter can be changed with the channel 2 threshold control, although along with the channel 2 de-ess, ratio, attack, release and auto controls, this has no effect on the operation of the unit.
Control Operations 6.10 De-ess The DE-ESS control determines how much gain reduction the BROADBAND de-esser applies to the signal when a sibilant sound is detected. The maximum amount of gain reduction available in this mode is approximately 20dB. The dynamic settings for the broadband de-esser are set automatically by the DPR422 and are optimised for general vocal work.
are used. The setting of these controls should broadly follow the directions given in the respective parts of this manual. The below threshold and gain reduction meters are used to monitor the operation of the HF de-esser. The DEESS control, active and high LED’s play no part in HF DE-ESS mode and are automatically disabled when the DE-ESS HF mode is activated.
Metering displays 7.0 Meter displays 7.1 Input Meter The INPUT METER switch is used in conjunction with the OUTPUT LEVEL meter to allow the input signal to be displayed. The switch has a momentary action to ensure that the meter is not inadvertently left showing input level. This facility becomes extremely useful when used in conjunction with the CHANNEL IN switch.
7.3 Gain Reduction Meter Once the input signal has exceeded the threshold point on scale, the compressor starts to operate, and gain reduction will occur. The amount of gain reduction being used is displayed on the GAIN REDUCTION meter. Gain reduction is a useful way of expressing compressor action as it gives an instantaneous indication of how much the signal is actually being processed.
General applications 8.0 General Applications 8.1 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.
Fig 8.2 Operating level and headroom 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. However, in most types of program there are instantaneous short duration level peaks or transients, which would be difficult to anticipate and impossible to respond to in the required time.
General applications 8.3 The effect of compression & limiting on sound 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 8.4a & b, assuming that all Fig 8.3a High threshold level Fig 8.
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. Limiters do not make-up the gain reduction. The range provided by the DPR 422 on its ratio and release controls is sufficient to allow its use either as a compressor or limiter. For limiter applications, the release fast switch should generally be out.
Operations and applications 9.0 Operation and applications 9.1 Compression Rotate the THRESHOLD control anticlockwise until the BELOW THRESHOLD meter is fully illuminated and an appropriate amount of gain is indicated on the GAIN REDUCTION meter. This operation will be accompanied with a drop in output level, as indicated by the OUTPUT METER. The output GAIN CONTROL should now be adjusted to reinstate the output level.
HF De-essing with full Dynamic control Rotate the THRESHOLD control anticlockwise until the BELOW THRESHOLD meter is fully illuminated and an appropriate amount of gain reduction is indicated on the GAIN REDUCTION meter. The FREQ control and THRESHOLD control can now be fine tuned to achieve the desired effect whilst listening to the program. Gain compensation will not normally be required when de-essing.
Troubleshooting 10.0 Troubleshooting Problem: No output. Solution: Is the Mains Power connected? Check the connections. See fuse failure (below). Do you have an input signal? Check the Input and Output connections. Are the power amplifiers switched on? Problem: Fuse failure. Solution: The mains supply fuse is unlikely to blow without an electronic fault being present. If the CORRECT replacement fuse blows again at switch on or after a short interval, switch off the unit and arrange for servicing.
Warranty Info 11.0 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.
Specifications 12.0 Specifications General Input Impedance Input Headroom Input CMRR Output level Output Impedance Output Gain Frequency Response Noise Dynamic Range Cross Talk Distortion 10k ohm balanced or unbalanced >+20dBu >-50dB (30Hz-20kHz) >+20dBu into 600 ohms or greater <50 ohms unbalanced or unbalanced +/-20dB continuously variable 10Hz-80kHz (+/-3dB) -96dBu (22Hz to 22kHz) >117dB >-85dB (20Hz to 20kHz) <0.005%THD (80kHz measurement BW) 20Hz-20kHz. Typically 0.
Glossary 13.0 Glossary Active Active electronic circuits are those which are capable of voltage and power gain by using transistors and integrated circuits. Amplitude Refers to the voltage level or intensity of a signal, and is usually measured in voltage or decibels. Attack Time The amount of time taken for the compressor or limiter to kick in and start gain reduction once the input signal has exceeded the threshold level.
Glossary presents in the original. Harmonic distortion refers to added frequencies that are overtones to the fundamental frequency. Intermodulation distortion refers to added frequencies that are sum and difference values derived from the beating together of two frequencies. Drop-in A term used to describe the way in which new equipment, or a hitherto unused function of equipment already connected, can be switched into a live sound system without causing unwanted effects, i.
gain reduce. Transient Unity Gain A sudden burst of energy in an audio signal which only lasts for a small period of time relative to the rest of the signal. The level of these transients can often reach 10 times (+20dB) or so above the normal operating level of the audio equipment, and may cause distortion of headroom is inadequate. Where output level is equal to input signal level.
Index Index A Attack Audio connections Inputs Outputs Side Chain Inputs Side Chain Outputs AUTO 15 10 10 11 12 16 B Breathing 16 17 23 26 24 15 16 17 18 18 18 17 13 14 15 19 16 13 D De-ess De-ess HF De-essing application Broadband HF Dimensions Dynamic range 18 18 25 26 25 25 5 22 6 F Frequency 34 Gain Gain control Glossary 17 22 31 I 5 L Limiters effects of 23 24 M Mechanical installation Meters Below Threshold Gain Reduction Input Output 5 20 21 20 21 O Operating Level 13 P Peak Limiti
T Threshold Troubleshooting 13 28 U Unpacking 7 V Voltage Controlled Attenuator Voltage selection 13 6 W Warranty 29 35
User Notes 36
User Notes 38
User Notes 40
