User manual DBX 160A

[. . . ] MODEL 160A COMPRESSOR LIMITER ® A Harman International Company WARNING CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN FOR YOUR PROTECTION, PLEASE READ THE FOLLOWING: WATER AND MOISTURE: Appliance should not be used near water (e. g. near a bathtub, washbowl, kitchen sink, laundry tub, in a wet basement, or near a swimming pool, etc). Care should be taken so that objects do not fall and liquids are not spilled into the enclosure through openings. POWER SOURCES: The appliance should be connected to a power supply only of the type described in the operating instructions or as marked on the appliance. [. . . ] For drum kit submixes (e. g. , mixing multiple drum tracks to two tracks while using two 160As for compression), consider backing off the COMPRESSION RATIO on each 160A (down to 2:1) to avoid an excess of cymbal Òsplattering. Ó 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). Compressors have also been used to bring vocals to the forefront of a mix in volume-restricted studios (e. g. Start by adding a foam windscreen to the mic (if it doesn't have one). With your mouth approximately 2 inches from the mic, sing the vocal part, but with less volume than normal. 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 frequencyweighted 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 program. 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 dbx 160A COMPRESSOR / LIMITER ® PROFESSIONAL PRODUCTS As a general rule, compressors should be as close to the amplifiers as possible in the signal chain. If the 160A is placed before the EQ (equalizer), for example, a potentially damaging boost in the EQ won't be seen by the 160A and the speakers may be damaged. (see Multi-way speaker systems, page 9. ) For maximum sound pressure levels, large sound reinforcement systems frequently use a separate compressor on each output of the electronic crossover(s). For a stereo sound-reinforcement system, stereo strapping cables should be run between the 160As in each band (low-low, mid-mid, etc. ). Raising Average Level in PA Systems Limiting (i. e. , compression at high ratios like °:1) also benefits intelligibility by allowing low-level input signals to be reproduced through the system at higher volume. [. . . ] This switch disconnects the input XLR pin 1 (the shield) from the 160A's chassis ground. We advise starting with the switch in the LIFT position (shield disconnected at the 160A input). If hum persists try disconnecting the shield on one or more of your cables, preferably at the input of a device, not at the output: Ground the shield of the input cable at the source device (leaving it unconnected at the 160A's INPUT) and ground the shield of the output cable to the ground terminal of the 160A (leaving it unconnected at the receiving device). The shield is pin 1 on the XLR, SLEEVE on a 1/4Ó TRS. TECHNICAL SUPPORT, FACTORY SERVICE Technical Support/Factory Service The 160A is an all-solid-state product with components chosen for high performance and excellent reliability. [. . . ]