dbx 160A Instructions Manual Download Page 11

 

dbx 160A  COMPRESSOR / LIMITER

Negative ratios can also be used to prevent musicians from continually increasing the volume of their instrument (e.g., 
in live applications where there is no sound engineer to control the house levels). With their signal compressed by a neg-
ative COMPRESSION RATIO, each volume increase initiated at the instrument or amp would actually decrease the 
volume level at the final mix.
Fattening Kick Drums and Compressing Other Drums

Weak, flabby kick drums often have too much boom, and not enough slap. To tighten them up, start with the 160A 
adjusted for a medium to high COMPRESSION RATIO (e.g., 6:1), adjust the THRESHOLD control so that the GAIN 
REDUCTION meters show 15dB of gain reduction, then increase the COMPRESSION RATIO if necessary. In 
OverEasy mode, the 160A 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 160A 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. 

For drum kit submixes (e.g., mixing multiple drum tracks to two tracks while using two 160As for compression), con-
sider backing off the COMPRESSION RATIO on each 160A (down to 2:1) to avoid an excess of cymbal “splattering.” 
In larger multitracking systems, compress the kick and snare separately. A further possibility (if you have two more 
compressors) is to heavily compress a stereo submix of toms and leave the remaining percussives unaffected.
Raising a Signal Out of a Mix

Since reducing dynamic range increases the average signal level by a small amount, a single track can be raised out of a 
mix by boosting its level slightly and applying compression. Start with a 2:1 COMPRESSION RATIO and a relatively 
low THRESHOLD setting (-20dB). Adjust both controls as necessary.

Compressors have also been used to bring vocals to the forefront of a mix in volume-restricted studios (e.g. home stu-
dios). Start by adding a foam windscreen to the mic (if it doesn't have one). Set the COMPRESSION RATIO to 10:1 and 
the THRESHOLD to -10dB. With your mouth approximately 2 inches from the mic, sing the vocal part, but with less 
volume than normal. Use phrasing to give the part some intensity. An equalizer (e.g., a dbx 20 or 30 Series Graphic 
Equalizer) or a vocal effects device (e.g., reverb, delay, distortion) can be added to further toughen the performance.

It is also possible to separate certain vocals or instruments from a mono program already mixed: refer to frequency-
weighted compression on page 8.

Note: When compressing a stereo program with a pair of 160As, the factors affecting a compression curve and the actual COMPRESSION RATIO and 
THRESHOLD settings, are like those previously covered with reference to single channels of program material. However, it will generally be found that 
large amounts of compression are more audible in a mixed stereo program than they might be on the separate tracks that were mixed to create the pro-
gram.

Preventing Analog Tape Saturation

With programs of widely varying 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, below).
Preventing Digital Overload

Some digital recorders and samplers produce audible distortion when they exceed their headroom (i.e., the range above 
their normal operating level). The 160A effectively ensures that audio input does not overload a digital recorder's D/A 
(digital-to-analog) converters. The 160A can perform this compression quietly enough for all digital media. Set the 
160A for limiting with Hard Knee mode On, the COMPRESSION RATIO to 

:1, and set the THRESHOLD 2 to 3dB 

below the overload point of the recorder.
Speaker Protection (Auditoriums, Churches, Mobile DJs and Sound Systems)

Compressors are frequently used to prevent excessive program levels from damaging drivers in a sound-reinforcement 
system (whether you're doing auditorium, church, or club sound engineering, or are a mobile DJ for small dances, or 
like to push the limits your home's audio entertainment center). Set the 160A for limiting (Hard Knee mode On, with a 
COMPRESSION RATIO of 10:1 or greater) and adjust the THRESHOLD to provide 15dB or more of compression (just 
a few dB below the input clip). For low-level signals, the 160A won't change gain, but if large signals come along, the 
gain will be reduced to prevent clipping and save sensitive system components from excessive heat buildup or other 
type of damage .

In circumstances where the 160A is expected to cause no change in gain unless an emergency arises (wildly excessive 
levels), some operators set Hard Knee mode On, the COMPRESSION RATIO to 

:1, and the THRESHOLD to the 

highest permissible level.

7

Summary of Contents for 160A

Page 1: ...MODEL 160A COMPRESSOR LIMITER ...

Page 2: ...r 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 A MAINS SOCKET OUTLET WITH A PROTECTIVE EARTHING CONNECTION The cores in the mains lead are col...

Page 3: ...or to a retailer if you purchase a similar new one For Countries not mentioned above please contact your local authorities for a correct method of disposal By doing so you will ensure that your disposed product undergoes the necessary treatment recovery and recycling and thus prevent potential negative effects on the environment and human health IMPORTANT SAFETY INFORMATION DECLARATION OF CONFORMI...

Page 4: ......

Page 5: ...tents Quick Set Up 2 Inspection 2 Introduction 2 Applications 3 Operating Controls 3 Operating Notes 5 Connecting the 160A to your System 10 Installation Considerations 12 Technical Support Factory Service 13 Warranty 13 Specifications 14 1 ...

Page 6: ...stereo coupled with a dbx 160XT 160X 160 161 or 162 unit True Power Summing When two 160A units are slaved together the RMS energy of the signal presented to the slave unit is summed with the RMS energy of the signal presented to the master unit to prevent phase cancellation of the two signals from causing unmusical compressor action LED Displays 19 Segment LED Display for high resolution monitori...

Page 7: ...button to select the OverEasy compression characteristic The amber THRESHOLD LED turns On when the signal is in the OverEasy region When this button is out the 160A operates as a hard knee compressor limiter In Hard Knee mode the threshold of compression is defined as that point above which the output level no longer chang es on a 1 1 basis with changes in the input level See Figure 1 In OverEasy ...

Page 8: ...ut level For proper unbalanced operation the unused pin either pin 2 or 3 MUST be grounded Nominal output signal level is 4dBu into 600Ω and typical maximum output level is 25dBu into 600Ω This jack accepts XLR type connectors wired pin 2 HOT pin 3 COLD and pin 1 chassis ground For applications which require a true transformer output an optional output transformer can be installed Contact our Cust...

Page 9: ...ut signals which fall below this level will pass through the 160A unprocessed except for fixed gain changes directed by the OUTPUT GAIN control See Figure 1 Page 4 In OverEasy Mode OVEREASY button depressed signals begin to gradually activate the 160A s gain change circuitry as they approach the THRESHOLD reference level and they do not get fully processed in the manner defined by the RATIO contro...

Page 10: ...approximately 4 1 then adjust the THRESHOLD control for 10dB to 12dB of gain reduction Compression less ens the loudness variations among the strings and increases the bass inherent sustain Other instruments such as horns vary in loudness depending on the note being played and benefit similarly To control untimely volume shifts in hot guitar or synth parts and to keep them from overloading your ta...

Page 11: ... g a dbx 20 or 30 Series Graphic Equalizer or a vocal effects device e g reverb delay distortion can be added to further toughen the performance It is also possible to separate certain vocals or instruments from a mono program already mixed refer to frequency weighted compression on page 8 Note When compressing a stereo program with a pair of 160As the factors affecting a compression curve and the...

Page 12: ... compensated for The 160A as a Line Amplifier To use the 160A as a line amplifier adjust the COMPRESSION RATIO control fully counterclockwise 1 1 position THRESHOLD fully clockwise 20 and OUTPUT GAIN to whatever setting is required for the application Remember excessive gain may lead to output clipping of high level signals To add compression adjust the COMPRESSION RATIO and the THRESHOLD controls...

Page 13: ... must be added By inserting an equalizer in the detector path to the 160A it can be made more sensitive to frequencies in the range handled by the sensitive drivers The system can then be run at higher lev els and will only be dropped back when damaging signals are present Using a Filter in the Level Detector Circuit The results of inserting a filter in the level detector circuit are basically the...

Page 14: ... of a single unified panorama of sound The stability of the psy choacoustic image of each sound source within the stereo program depends upon its ability to maintain a specific phase and amplitude relationship from left to right channel If two independent compressors are used to process the stereo program a loud sound occurring in one channel will cause the image to shift to the opposite side This...

Page 15: ...zer s volume control and boost the track s output level using the 160A s OUTPUT GAIN control or the mixer s volume fader the latter here is great for track fade outs If the 160A is post fader i e the 160A is connected to mixer inserts so that the compression effect occurs after the level set by the mixer channel s volume fader adjusting the mixer s volume fader changes the input level and the amou...

Page 16: ...tip ring sleeve phone jacks and XLR type jacks The 160A can be used with either balanced or unbalanced sources and outputs can be used with either balanced or unbalanced loads provided you use proper cabling A balanced line is defined as two conductor shielded cable with the two center conductors carrying the same signal but of opposite polarity with respect to ground An unbalanced line is general...

Page 17: ... 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 material if it is available Mark the package with the name of the shipper and with the following words in quotes in red DELICATE INSTRUMENT FRAGILE Insure the package properly Ship prepaid not collect Do not ship parcel post ...

Page 18: ...dBm Dynamic Range 113dB Gain Adjustment Range Variable from 20dB to 20dB Threshold Range 40dBu to 20dBu Threshold Characteristic Selectable OverEasy or Hard Knee Compression Ratio Variable 1 1 to 1 thru to 1 1 60dB Maximum Compression Attack Time Program Dependent Typically 15ms for 10dB 5ms for 20dB 3ms for 30dB Release Time Program Dependent Typically 8ms for 1dB 80ms for 10dB 400ms for 50dB 125...

Page 19: ...dbx 160A COMPRESSOR LIMITER NOTES 15 ...

Page 20: ... Sandy Pkwy Sandy Utah 84070 Phone 801 568 7660 Fax 801 568 7662 Questions or comments E mail us at customer dbxpro com or visit our World Wide Web home page at www dbxpro com 18 2040V C 12 08 10 Printed in China ...

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