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
Compressors have also been used to bring vocals to the forefront of a mix in
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
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
Speaker Protection (Auditoriums, Churches, Mobile DJs and Sound Systems)
Compressors are frequently used to prevent excessive program levels from damaging drivers in a
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.
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