Mackie 1642-VLZ4 Owners Manual - Page 17

Owner's Manual 34. Low Cut The low cut switch (not present on channels 13-16), often referred to as a high pass filter, cuts bass frequencies below 75 Hz at a rate of 18 dB per octave. This ain't no thrown-in dime-store filter - an 18 dB per octave curve requires an elaborate circuit. Nothing but the best for you. We recommend that you use this on every sound source except kick drum, bass guitar, or bassy synth patches. These aside, there isn't much down there that you want to hear, and filtering it out makes the low stuff you do want much more crisp and tasty. Not only that, but low cut can help reduce the possibility of feedback in live situations, and it helps to conserve amplifier power. With low cut, you can safely boost low EQ. Many times, bass shelving EQ can really benefit voices. Trouble is, adding low EQ also boosts the subsonic debris: Stage rumble, mic handling clunks, wind noise and breath pops. Low cut removes all that debris so you can boost the low EQ without blowing your subwoofers. Here's a frequency curve of low EQ combined with low cut: +15 +10 +5 0 -5 -10 -15 20Hz 100Hz 1kHz 10kHz 20kHz 35. Aux 1, 2, 3, & 4 These four knobs tap a portion of each channel's signal, mix them together and send them to the aux send [6] outputs. They are off when turned fully down, deliver unity gain at the center detent, and can provide up to 15 dB of gain turned fully up. Chances are you'll never need this extra gain, but it's nice to know it's there if you do. The aux send outputs are then patched to parallel effects processor inputs or stage monitor amp inputs. Aux sends 1 and 2 levels are controlled not only by the channel's aux knobs, but also by the aux send [49] master knobs. Aux sends can also be used to generate separate mixes for recording 34 or "mix-minuses" for broadcast. By using aux 1 or 2 in the pre [35] mode, these mix levels can be obtained 35 independently of a channel's fader [25] settings. 36 We recommend going into a stereo reverb in mono and returning in stereo. We have found that on most "stereo" reverbs, the second input just ties up an extra aux send and adds nothing to the sound. There are exceptions, so feel free to try it both ways. Should you choose to use two aux sends, use the "odd" aux (1 or 3) to feed its left input and the "even" 33 aux (2 or 4) to feed the right input. Remember, if you're also dealing with a stereo source signal, you'll want to follow the sides - use the odd aux on the channel carrying the left side and the even aux on the channel carrying the right. 36. Pre This switch determines the tap point of aux 1 and 2. Generally, "post" sends are used to feed effects devices, and "pre" sends are used to feed your stage monitors. See the "Pre vs. Post" diagram below. Aux 3 and 4 are ­always in post mode. INPUT TRIM INSERT LOW CUT MUTE EQ FADER PAN ASSIGN 'PRE' SIGNAL 'POST' SIGNAL AUX 1 PRE SWITCH AUX 2 In post mode (switch up), aux 1 and 2 will follow the EQ [32], low cut [34], fader [25], and mute [30] settings. If you fade the channel, you fade the send. This is a must for effects sends, since you want the levels of your "wet" signals to follow the level of the "dry." In pre mode (switch down), aux 1 and 2 follow the gain and low cut settings only. EQ, pan, fader, and mute settings have no effect on the pre sends. This is the preferred method for setting up stage monitor feeds - they'll be controlled independently of the fader and mute moves. Owner's Manual 17