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BSS Audio DPR 402 User Manual

Compressor peak limiter de-esser
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Summary of Contents for BSS Audio DPR 402

  • Page 1 DPR 402 User Manual...
  • Page 2 V3.0 13 May 1997 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.

  • Page 3: Table Of Contents

    Contents Contents Compressors and Limiters The need for Gain Control Compressors and Limiters The effect of Compression on sound Compression Attack, Release and Ratio De-essing and Peak Limiting The BSS DPR-402 Earthing Requirements Unpacking Mechanical Installation Mains Power Connection Input and Output Connections - Rear Panel Facilities.
  • Page 4 Contents 12.0 De-essing and Peak Limiting 12.1 De-essing 12.2 Broadband De-essing and controls 12.3 HF Only De-essing and Controls 12.4 Peak Limiting 13.0 Rear Barrier Strip 14.0 Operation and Applications 14.1 Compression 14.2 De-essing 14.4 De-ess Wide with Full Dynamic Control 14.3 De-essing Wide with Simultaneous Compression...

  • Page 5: Compressors And Limiters

    Compressors and Limiters Compressors and Limiters 1.1 The need for 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 Gain Control aircraft.

  • Page 6: Compressors And Limiters

    Compressors and Limiters Fig 1.2 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.

  • Page 7: The Effect Of Compression On Sound

    The effect of Compression The effect of Compression on sound 2.1 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.

  • Page 8: Attack, Release And Ratio

    The effect of Compression 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.

  • Page 9: De-Essing And Peak Limiting

    De-essing and Peak Limiter The DPR-402 De-essing and Peak Limiting A common problem encountered when amplifying the human voice is the large amount of High Frequency energy, heard as the sibilant 'sss' sound. These high frequency or sibilant sounds can reach levels considerably greater than the normal voice level, and will result in signal break-up or distortion.

  • Page 10: Earthing Requirements

    Like all BSS Audio equipment, the DPR-402 has been designed to withstand harsh treatment on the road, yet has a specification to satisfy the most stringent studio and broadcast work.

  • Page 11: Unpacking

    Unpacking Those units supplied to the North American market will have an integral moulded 3 pin connector which is provided to satisfy required local standards. 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: 90VAC up to 132VAC on the 115V position and 190VAC up to 264VAC on the 230V position.
  • Page 12 Getting to know the DPR-402 Fig 6.1 Front Panel Fig 6.2 Rear Panel...
  • Page 13 All numbers in bubbles refer to Section numbers.

  • Page 14: Mechanical Installation

    Mechanical Installation Mechanical Installation A vertical rack space of 1U (1¾" / 10½mm) deep is required. Ventilation gaps are unnecessary (See Figure 7.1). If the DPR-402 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.

  • Page 15: Mains Power Connection

    Mains Power Connection Mains Power Connection Voltage: The DPR-402 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 8.1 Mains fuse on rear panel.

  • Page 16: Input And Output Connections - Rear Panel Facilities

    Inputs/Outputs Input and Output Connections - Rear Panel Facilities. 9.1 Inputs The input (See figure 9.1) is a 10K ohm balanced type on a standard 3 pin female XLR which will accept levels up to +20dBv. The '+' or in-phase connection is to pin 3 and the '-' or out-of-phase connection is to pin 2.

  • Page 17: Stereo Link

    9.3 Stereo Link This facility (See figure 9.4) enables the two channels of the DPR-402 to be used in a stereo system, with the result that there is no image shifting under comparison on either channel. This switch actually couples the detector outputs from both channels together, so that either one responds to the largest signal present.

  • Page 18: Compression Controls

    Compression Controls 10.0 Compression Controls In the DPR-402, the gain reduction is achieved using a Voltage Controlled 10.1 Threshold Attenuator with a range or operational 'window' of 30dB. This means that it is capable of reducing the input signal by up to 30dB or 30 times (the GAIN REDUCTION METER displays this window showing how much of it is being used).

  • Page 19: Attack Time

    Fig 10.3 The effect of Ratio on the Output Signal 10.3 Attack Time The response of the DPR-402 compressor to signals above the threshold point is further defined by the ATTACK TIME control (See figure 10.4). The DPR-402 ATTACK TIME control has 11 calibrated positions from 50 microseconds to 100 milliseconds, and determines how quickly the compressor responds to signals once the threshold is exceeded.

  • Page 20: Auto Time

    Compression Controls 10.5 AUTO TIME This feature of the DPR-402 is provided to overcome some of the settling problems associated with the attack and release time control features. It is accessed by switching the released time control to the 'AUTO' position, whereupon the circuit automatically adjusts itself to provide the required attack and release time settings, depending on the program type (See figure 10.6).

  • Page 21: Bypass Switch

    10.7 BYPASS switch The BYPASS switch (See figure 10.8) enables you to bypass quickly all functions of the DPR-402 by connecting the output directly to the input. When the switch is pressed, and the light is on, all DPR-402 functions are present on the output signal.

  • Page 22: Compression Meters

    Compression Meters 11.0 Compression meters 11.1 Below Referring back to section 10.1, where we discussed the VCA window of operation, the five LEDs (See figure 11.1) of the BELOW THRESHOLD meter Threshold and will give you an indication of the input signal in relation to this window. Gain Reduction You will notice that the LED marked 'TH' is half-on all the time.

  • Page 23: Output Level Meter And Meter Input Switch

    Fig 11.3 Compression expressed as Gain Reduction The range of the gain reduction meter is set to display the 27dB operating window. In practice, over 30dB of range is available before noticeable distortion occurs. Another piece of information also displayed by these meters is the amount of gain reduction still available from the VCAs window of operation.

  • Page 24: Mon S.c. Switch

    Compression Meters The METER INPUT 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 (See figure 11.5).

  • Page 25: De-Essing And Peak Limiting

    De-essing and Peak Limiting 12.0 De-essing and Peak Limiting In section 3 the problems with high frequency energy, also known as 12.1 De-essing sibilance, were discussed. The DPR-402 provides for this facility in either of two distinct ways: Broadband de-essing and HF only de-essing. Under program conditions, once the detector detects excessive amounts of frequency, it will start to gain reduce the program level as in normal compression.

  • Page 26: Hf Only De-Essing And Controls

    De-essing and Peak Limiting Fig 12.1b DE-ESS Controls In utilising the controls in figure 12.1b, no other compressor controls will be required. If no compression is being used, the ratio or threshold controls should be set to OUT. The frequency control should be set to coincide with the lowest frequency of the sibilance, and the de-ess control be used to give the required amount of gain reduction.

  • Page 27: Peak Limiting

    To aid the correct setting of the FREQ control in relation to the audible sibilance, the source program can be listened to through the internal de-ess filter by depressing the MON S.C. switch. This replaces the normal signal at the output connector with the output of the de-ess filter. The effect of de-essing at various frequencies on a program is shown in figure 12.3.

  • Page 28: Rear Barrier Strip

    Rear Barrier Strip 13.0 Rear Barrier Strip The DPR-402s rear barrier strip provides an interface with the main compressor section, allowing for various configurations which utilise the internal facilities as well as external equipment. For correct operation of the unit, make sure that both the SUBTRACT and CONTROL side chain points are closed, either by links or by externally connected equipment.

  • Page 29: Operation And Applications

    Operation/Applications 14.0 Operation and Applications 14.1 Compression Barrier strip linking B-C and D-G (as factory set). Initial settings. Controls Position MODE SWITCH Compress THRESHOLD RATIO ATTACK RELEASE Auto GAIN CHN BYPASS In (Illuminated) DE-ESS THRSHLD FREQ PK LIM THRSHLD 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.

  • Page 30: De-Ess Wide With Full Dynamic Control

    Operation/Applications 14.3 De-essing Barrier strip linking B-C and D-G (as factory set). Wide with Initial settings. Simultaneous Set all compressor controls as required (refer to section 14.1). For optimum de- essing effect, no more than 10-15dB of compression should be used. If Compression compression is not required, then set THRESHOLD to OUT.

  • Page 31: De-Ess Hf With Full Dynamic Control

    14.5 De-ess HF with Barrier strip linking B-C and D-G (as factory set). Full Dynamic Initial settings. Control Controls Position MODE SWITCH De-ess HF THRESHOLD RATIO Infinity ATTACK 50 microseconds RELEASE 50 milliseconds GAIN CHN BYPASS In (Illuminated) DE-ESS THRSHLD FREQ 4kHz PK LIM THRSHLD...

  • Page 32: Applications Using The Barrier Strip

    Barrier Strip Applications 15.0 Applications using the Barrier Strip 15.1 Patching of Control Side Chain External Equipment A very common requirement is to make the threshold of the compressor frequency conscious by inserting a graphic or parametric equaliser into the control side chain.

  • Page 33: Repatching Of The Barrier Strip For Other Uses And Special Effects

    15.2 Repatching of The following table lists many of the possible uses of the DPR-402. This is not an exhaustive list, and other combinations may be tried. To obtain the full the Barrier Strip for benefits of its versatility, a simple understanding of how it works is required other uses and (refer to section 13).
  • Page 34 Barrier Strip Application MODE SUBTRACT CONTROL S/C LINK S/C LINK NARROW L.F. CONTROL COMPRESSION Only frequencies below that set on the FREQ control are compressed. Low frequencies are compressed without modulating the high frequencies, which pass unattenuated. The PEAK LIMITER and DE-ESSER should not normally be used in this mode.

  • Page 35: Stereo Linking

    MODE SUBTRACT CONTROL S/C LINK S/C LINK AMPLITUDE CONTROLLED MIXING (2) EXT SIG EXT SIG to G to B As above, but the external signal will be (control) (sum) summed with the main signal, but this time under control of the same, or another, external control input.
  • Page 36 Barrier Strip Applications Fig 15.2 BARRIER STRIP linking for improved stereo coupling Channel 2: Channel 1: Controls Position Controls Position STEREO LINK SW MODE SWITCH Compress MODE SWITCH Compress THRESHOLD THRESHOLD As Required RATIO RATIO As Required ATTACK ATTACK As Required RELEASE RELEASE As Required...

  • Page 37: Troubleshooting

    16.0 Troubleshooting Problem: No Output Solution: Is the Mains Power connected (See section 8) Check the connections. See fuse failure (below). Do you have an input signal? Check the Input and Output connections (See section 9) Are the power amplifiers switched on? Problem: Fuse Failure Solution:...

  • Page 38: Glossary

    A term used to describe the fluctuations of background noise resulting from the compressor action. Bright up A term used by BSS Audio to describe an increase in the intensity of an LED or fluorescent meter, indicating that the level it is measuring has exceeded a maximum set level.
  • Page 39 The same scale as for dBu as before, except that 0dBV = 1.0 Volts. Distortion Any modification of a signal which produces new frequency components not 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.
  • Page 40 Glossary Release Time The time required for a compressor or limiter to restore its gain to normal, after the input signal has fallen below threshold. Sibilance The distortion caused by large high frequency signals superimposed onto a normal signal, such as the 'sss' sounds of human voice. Threshold The pre-settable level above which a compressor or limiter will commence to gain reduce.

  • Page 41: General

    Specifications 18.0 Specifications General Input Impedance: 10k ohm balanced or unbalanced. Input Headroom: >+20dBv. Input CMMR: Better than -50dB 30Hz-20kHz. Typically -65dB at 1kHz. Output level: >+20dBv into 600 ohms or greater. Output Impedance: <1 ohm unbalanced. Output Gain: ±20dB continuously variable. Frequency Response: ±1dB 25Hz to 20kHz.

  • Page 42: Peak Limiter

    Specifications Peak Limiter Threshold Range: +4dBv to +20dBv continuously variable. Ratio: >20:1. Attack Time: 150 microseconds, fast setting. 750 microseconds, slow setting. Release Time: 100 milliseconds, fast setting. 500 milliseconds, slow setting. Notes Note 1: Harmonic distortion will increase with reduced frequency and shorter time constants, which is inherent in this type of equipment.
  • Page 43 Stereo Switch (Rear Panel): Couples channel 1 and channel 2 control signals for stereo operation. Indicated on the front panel by an LED. Rear Connections: INPUT: XLR 3-31 or equivalent (Balanced) OUTPUT: XLR 3-32 or equivalent (Unbalanced) ACCESS POINTS: Barrier strip, providing control and subtract side chain insertion points including HP and LP filter sends, pre-emphasis and de-emphasis network sends;...

  • Page 44: Warranty Information

    19.0 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.
  • Page 45 Index Index Attack Time 8, 19 Auto Time Below Threshold. See Compression meters; Compression meters: Below Threshold Bypass switch Compression Compression meters Below Threshold Gain Reduction Input Level Meter Input De-essing 9, 25, 26, 30, 31 Broadband HF with Full Dynamic Control HF-Only Wide with Full Dynamic Control Wide with Simultaneous Compression...
  • Page 46 Index Mains Connection Meter Input. See Compression meters: Meter Input Mode switch MON S.C. switch Operation Compression De-essing Output Connections Output Level. See Compression meters: Input Level Peak Limiter Switch Peak Limiting 9, 27, 31 Power ON. See Mains Connection Rack space..

  • Page 47: User Notes

    User Notes...
  • Page 48 User Notes...

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