Mackie SR408 / SR568 Owner's Manual - Page 20

LINE MIC +48 PH TRIM 40 0 60 -20dB +40dB 0 GAIN U AUX 1 +15 U OO OO OO OO OO OO OO OO 2 +15 U 3 +15 U 4 +15 PRE U 5 +15 U 6 +15 U 7 +15 U 8 +15 PRE FDR POST EQ CHANNEL The forty Channel strips placed on either side of the console look alike and function identically. They're loaded with professional features. Let's start at the top of a Channel and work our way down, but save the AUX send section for later. "U" LIKE UNITY GAIN Mackie consoles have a "U" symbol on almost every level control. This "U" stands for "unity gain," meaning no boost or cut in signal level. Once you have performed the Level-Setting Procedure , you can set every control at "U" and your signals will travel through the mixer at optimal levels. What's more, all the labels on our controls are measured in decibels (dB), so you'll know what you're doing level-wise if you choose to change a control's settings. Be aware that unity gain is also reliant on the position of the PAN knob. When panned center, there will be about 4dB of attenuation on each side to preserve "constant loudness" . CHANNEL INPUT CONTROLS A Channel's input controls manipulate the signal just after the MIC and LINE IN . From there, a line-level signal is sent on to the Channel output controls . +48 PH (PHANTOM POWER) Point Before: 48VDC power supply for condenser microphones. Point After: MIC input . This one's easy. If you have a condenser microphone plugged in, or any mic that requires 48VDC phantom power, engage this switch. If you have a dynamic microphone, or any mic that does not require phantom power, leave this switch up, although it won't do any harm if it's down (as long as you're using good quality balanced cables). The LED next to the switch glows when the power is on. TRIM Point Before: MIC and LINE IN jacks, summed at mic preamp input. Point After: Channel path, at 0/ (polarity reversal) switch. Have you read the Level-Setting Procedure yet? If not, go to item right now and read it - it's at the beginning of this manual. That procedure is basically "How to Use the Trim Control." We ask that you commit that procedure to memory. You'll be glad you did - it assures your incoming signal of being treated to the highest headroom and lowest noise possible. Signals entering through the MIC XLR jack have unity gain (no level boost or attenuation) with the knob fully down, and a 60dB boost fully up. Through the LINE IN TRS jack, there is 20dB of attenuation fully down and a 40dB boost fully up, with a "U" (unity gain) mark at 9:00. This 20dB of attenuation can be very handy when you are inserting a signal that is very hot, or adding a lot of EQ gain, or both. Without this "virtual pad," a scenario like this might lead to clipping (which is an automatic 15 yard penalty in the NFL). Ø (POLARITY REVERSAL) Point Before: MIC and LINE IN preamp output. Point After: HPF , Channel INSERT SEND and RETURN , EQ . Engaging this switch inverts the polarity of the incoming MIC or LINE IN signal. Although you'll want to start off with this switch disengaged (up), there's no right way or wrong way to set this switch - it's all based on which way sounds better, especially when auditioning the signal with its partner signals. For instance, by engaging the SOLO switches on all the drum Channels, you can experiment with polarity reversal of the overhead mics, the snare drum's underside mic, and so forth until you hit upon the right combination of settings. You'll want to make the "up" position the default setting for this switch so all the signals will have correct polarity (also known as "in phase") - and only reverse the polarity of Channels that you deem necessary. 20