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NOTE:

 The 166xs expansion ratio is internally fixed, at approximately 10:1. This ratio helps 

to eliminate the artifacts normally associated with common switch gates. Attenuation is 
>50dB.

SIDECHAIN (SC) ENABLE Switch and LED

This switch enables the 1/4” TRS connector of the sidechain, allowing external processing of 
the detector signal. It has no effect if there is nothing plugged into the sidechain loop; 
however the switch will still light indicating the sidechain is enabled. 

Expander/Gate RELEASE Control

This control determines the rate at which the gate closes once the signal at the INPUT or 
SIDECHAIN INSERT falls below the threshold. SLOW settings are useful for gating out noise 
present behind vocals and acoustic instruments. FAST settings are useful for tightening up the 
sound of percussion (e.g., kick or snare drum) and drying up leakage from other instruments 
into percussion tracks. 

NOTE:

 The gate release rate is “accelerating” in that the dB/Sec rate continually increases 

as the gate closes.

CONTOUR Button and LED

Depress this button to make the 166xs detection circuitry less sensitive to low frequency 
energy, preventing this energy from “punching holes” in the sound, especially with mixed 
program. With the CONTOUR button Out, the 166xs detector is frequency-independent. The 
CONTOUR LED turns On when the CONTOUR button is depressed.

COMPRESSOR Section

GAIN REDUCTION Meter

This meter displays how much the signal is being attenuated by the compressor and the gate. 

Compressor THRESHOLD LEDs

These three LEDs indicate the relationship of the input signal level to the threshold of 
compression. The green BELOW LED is On when the signal is below threshold and the red 
ABOVE LED is On when the signal is above threshold. When the 166xs is switched to OverEasy 
mode, the yellow LED is On when the signal is in the OverEasy region (See Figure 2). 

NOTE:

 Even though no input signal is being applied, it is normal for the LEDs to flicker 

when the power is applied or removed.

 

Compressor THRESHOLD Control

Adjust this knob to set the threshold of compression from -40dBu (7.8mVrms) to +20dBu 
(7.8Vrms). Setting the Compressor THRESHOLD control to +20dB will prevent all but the 
highest level peaks from being compressed. (Setting the Compressor RATIO to 1:1 will turn the 
Compressor off, regardless of the setting of the Compressor THRESHOLD control.)
In Hard Knee mode (OVEREASY button out), the THRESHOLD sets a reference level above which 
input signals will be processed by the 166xs gain change circuitry in the manner defined by 
the setting of the RATIO control. Input signals which fall below this level will pass through 
the 166xs unprocessed (except for fixed gain changes directed by the OUTPUT GAIN control). 
See Figure 1.

Section 2

Getting Started

6

dbx 166xs

Summary of Contents for 166xs

Page 1: ...User Manual UAL OMPRESSORÉ ÌiÀ ATE Professional Audio Equipment ...

Page 2: ...ent only to the power source indicated on the equipment rear panel To reduce the risk of fire or electric shock refer servic ing to qualified service personnel or equivalent If connected to 240V supply a suitable CSA UL certified power cord shall be used for this supply SAFETY INSTRUCTIONS NOTICE FOR CUSTOMERS IF YOUR UNIT IS EQUIPPED WITH A POWER CORD WARNING THIS APPLIANCE SHALL BE CONNECTED TO ...

Page 3: ...device may not cause harmful interference and UÊ this device must accept any interference received including interference that may cause undesired operation Operation of this unit within significant electromagnetic fields should be avoided UÊ use only shielded interconnecting cables U K MAINS PLUG WARNING A molded mains plug that has been cut off from the cord is unsafe Discard the mains plug at a...

Page 4: ...ction 3 Making Connections 10 3 1 Basic Connections 10 3 2 Specific System Connections 11 3 3 Installation Considerations 12 Section 4 Operating Notes 14 4 1 Expander Gate Applications 14 4 2 Basic Compressor Applications 15 Section 5 TechnicalSupport FactoryService 21 Section A Appendix 22 A 1 Technical Specifications 22 A 2 Wiring Diagrams 23 dbx 166xs Table of Contents ...

Page 5: ... the sound s PeakStop Limiting provides control of maximum peak levels at the output of the 166xs regardless of any other control PeakStop comes after the compression gating and other circuitry including the output gain so it sets an absolute limit for peak excursions before they reach the output s True RMS Level Detection senses the power in the program in a musical manner much the same as human ...

Page 6: ...ctory for service you MUST first contact Technical Support to obtain a Return Authorization Number No returned products will be accepted at the factory without a Return Authorization Number Please refer to the Warranty information on the following page which extends to the first end user After expiration of the warranty a reasonable charge will be made for parts labor and packing if you choose to ...

Page 7: ...returned to dbx WITH RETURN AUTHORIZATION from the factory where all parts and labor will be covered up to a period of two years A Return Authorization number must first be obtained from dbx The company shall not be liable for any consequential damage as a result of the product s use in any circuit or assembly 4 dbx reserves the right to make changes in design or make additions to or improvements ...

Page 8: ...ne input jack should be used at a time except for splitter applications where one input jack is used as an input and the other input jack is used as an output see Using the SIDECHAIN INSERT section on page 10 Since a given pair of channel input jacks e g Channel 1 XLR INPUT and Channel 1 1 4 INPUT are internally connected TIP Pin 2 RING Pin 3 SLEEVE Pin 1 if one of the jacks is unbalanced then the...

Page 9: ...NPUT jack at an impedance of 2k The TIP acts as a Return for equipment to feed the 166xs detector circuitry such as an equalizer for de essing or frequency sensitive gating compression You can also drive the 166xs SIDECHAIN INSERT with the output of most equipment by using a 1 4 mono phone plug Input impedance is greater than 10kΩ NOTE When a cable is plugged into this jack it automatically breaks...

Page 10: ...dent The CONTOUR LED turns On when the CONTOUR button is depressed COMPRESSOR Section GAIN REDUCTION Meter This meter displays how much the signal is being attenuated by the compressor and the gate Compressor THRESHOLD LEDs These three LEDs indicate the relationship of the input signal level to the threshold of compression The green BELOW LED is On when the signal is below threshold and the red AB...

Page 11: ... threshold When an input signal is above the THRESHOLD reference level the setting of this control determines the number of decibels dB by which the input signal must change in level to produce a 1dB increase in the signal level at the output of the 166xs A setting of 2 1 indicates an input output ratio wherein a 2dB increase in signal above threshold will produce a 1dB increase in output signal A...

Page 12: ...with the threshold of compression The OUTPUT GAIN control is especially useful to compensate for the RMS level decrease which results from the 166xs dynamic processing effects After you adjust the 166xs controls for the desired amount of compression and gating set the OUTPUT GAIN to add the same amount of gain that is shown on the GAIN REDUCTION meters For example if the average amount of gain red...

Page 13: ...ible to allow the rounding to occur Therefore for applications where you must not exceed a given ceiling set the PEAKSTOP control 1dB to 2dB below the ceiling The PEAKSTOP LED illuminates whenever peaks attempt to exceed PeakStop level and are reduced in amplitude If the PeakStop LED illuminates when the PEAKSTOP LEVEL control is set to 20dBu the headroom capabilities of the 166xs are being exceed...

Page 14: ...eyboard mixer as the signal is sent to main mixer between a DAT s output and an analog cassette input When using a chain of processors the 166xs may be placed either before or after effects or dynamic processors However if you are using the 166xs for speaker protection the compressor should be as close to the amplifier as possible in the signal chain We recommend you use common sense and experimen...

Page 15: ...d or not or the 166xs INPUT and OUTPUT can be wired to an Insert point In the latter case the signals will most likely be unbalanced It is important to note that the amount of compression is directly related to the level of the input signal However depending upon your system s setup it may not always be clear as to what volume controls in your chain affect input level and which affect output level...

Page 16: ...in 2 or 3 or the ring of a 1 4 stereo phone jack Note that grounding pin 2 of the XLR jack reverses the phase through the 166xs Sound Reinforcement To compress a live mix or to protect loudspeakers connect the 166xs between the source mixing board or distribution amp and the power amp s If multi way loudspeakers with low level electronic crossovers are used the 166xs s should go after the crossove...

Page 17: ...g a 600Ω load The phone jack TIP connection is internally wired to the XLR pin 2 the RING is wired to pin 3 and the SLEEVE shield is wired to pin 1 Note that pins 2 and 3 are the reverse of certain older dbx and other manufacturer s equipment but if the same connection is used at both the input and the output the signal will be correctly polarized in phase 166xs SIGNAL FLOW Figure 3 Signal Flow Ba...

Page 18: ...itial transient set the RELEASE control slow enough to allow the gate to remain open and capture the signal s entire envelope The gate can also be used to dry up a track or mix that has too much reverb or ambience Set the RELEASE control so that the natural decay of the sound is somewhat truncated Changing Sound Quality The 166xs gate can effectively change the sonic character of a sound because i...

Page 19: ...LEASE times To compress a mix begin with a low RATIO setting THRESHOLD set for a few dB of Gain Reduction and SLOW Attack and Release OVEREASY and CONTOUR buttons In Smoothing Out Variations in Microphone Levels Variations in signal level can occur when the distance between a vocalist and a mic changes or when the dynamics of a voice changes relative to a vocalist s range To smooth out these varia...

Page 20: ... mode the 166xs takes slightly longer to react than in Hard Knee mode and will therefore emphasize the slap at the beginning of the note and reduce the boominess of its body The 166xs also works well for tightening snare drums and tom toms and can be used with drum machines to effectively alter the character of any electronic drum sound Cymbals and tom toms can be effectively compressed using the ...

Page 21: ...g levels compression can prevent recording levels e g cymbal tracks in a final mix or drum kit submix from saturating tape tracks see frequency weighted compression on page 18 Preventing Digital Overload Digital recorders and samplers produce audible distortion when they exceed their headroom i e the range above their maximum operating level The 166xs effectively ensures that audio input does not ...

Page 22: ...g Your EQ to Reduce Feedback in Live Settings Indoor and Outdoor Concerts Churches You can use your 166xs and EQ equalizer to reduce feedback in clubs churches outdoor concerts and other live settings Patch or insert the 166xs into the main output of a mixer set the 166xs to Hard Knee mode and slowly increase OUTPUT GAIN until the first feedback ring occurs then set up the 166xs with its RATIO at ...

Page 23: ...pping the equalizer bands causes any sound with dominant energy in the affected register to pull the level up because the 166xs will detect a need for less compression De Essing To apply de essing to vocals i e a reduction of sibilance use a parametric equalizer in the SIDECHAIN circuit and set it to boost the specific frequency range where the vocal hiss or lisp occurs generally in the 4kHz 6kHz ...

Page 24: ...obtained with an equalizer as previously described Those frequencies passed by the filter are subject to compression or at least they are subject to considerably more compression than those frequencies outside the passband Because a passive filter can have insertion loss it may be necessary to lower the 166xs THRESHOLD setting to maintain a given amount of gain reduction within the filter passband...

Page 25: ...ur Limited Two Year Standard Warranty which extends to the first end user After the warranty expires a reasonable charge will be made for parts labor and packing if you choose to use the factory service facility In all cases you are responsible for transportation charges to the factory dbx will pay return shipping if the unit is still under warranty Shipping Instructions Use the original packing m...

Page 26: ...mpression Up to 40dB 1kHz SMPTE IMD Typically 0 08 10dBu 15dB Gain reduction COMPRESSOR Threshold Range 40dBu to 20dBu Threshold Characteristic Selectable OverEasy or Hard Knee Compression Ratio Variable 1 1 to Infinity 1 60dB Maximum Compression Attack Time Variable program dependent 3ms to 340ms for 15dB gain reduction Release Rate Variable program dependent 200dB Sec to 3dB Sec EXPANDER GATE Th...

Page 27: ... TYPE MALE FROM SOURCE DEVICE FROM SOURCE DEVICE TO NEXT DEVICE TO NEXT DEVICE FROM SOURCE DEVICE FROM SOURCE DEVICE TO NEXT DEVICE TO NEXT DEVICE FROM SOURCE DEVICE FROM SOURCE DEVICE TO NEXT DEVICE TO NEXT DEVICE FROM SOURCE DEVICE FROM SOURCE DEVICE TO NEXT DEVICE TO NEXT DEVICE FROM SOURCE DEVICE FROM SOURCE DEVICE TO NEXT DEVICE TO NEXT DEVICE FROM SOURCE DEVICE FROM SOURCE DEVICE TO NEXT DEV...

Page 28: ... 4PVUI 4BOEZ 1BSLXBZ r 4BOEZ 6UBI 1IPOF r BY Int l Fax 801 568 7583 Questions or comments Contact us at www dbxpro com Printed in China 18 0807 A ...

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