A little bit of summing, Pt. 1
The Analog Industries Guide To Summing, with your charming and handsome host, Chris Randall. (Pt. 1 of 3)
Why would someone want to sum outside a DAW, when the DAW has a perfectly good summing engine in it? Well, unless you use PT HTDM (and even then, really) the summing engine in your DAW sucks. Plain and simple. _Anyone_ that has a console and mixes stems instead of mixing "in the box" knows this. My experience is with Nuendo and Logic, so I'll refrain from knocking other DAWs, but a simple experiment is in order: make four group channels in your DAW, all four of which go to the main "stereo" output. Mix your song to these four stems. Once you have it sounding good, send each stem to its own pair of outputs, and do a unity gain mix on your console. Instant air, instant dynamics, and instant room in the mix. It's as plain as night and day. (Especially if you break those stems out while you're wearing headphones.)
Don't have an 8-output soundcard? Don't have a console? Don't know what the fuck I'm talking about? No biggie. This is the promised land that lives between pro-sumer making shit at home, and working in a "real recording studio" with, like, gear and stuff. It is quite a bit more expensive to do this than to just mix in the box, but not near as expensive as aquiring a proper console, etc. First, let's see what the hell a summing mixer is. We'll use the Dangerous Music 2-Bus LT for our example purposes.
The 2-Bus LT is the baby brother of the Dangerous 2-Bus, far and away the most popular summing mixer out there. Every single console, and in fact anything that combines two or more audio signals, has a summing mixer. What Dangerous did, much to everyone's surprise, is provide just the bit you actually need when mixing in the ProTools/Nuendo/Logic environment, the analog summing part. So you can think of this box as the part of the console after the faders but before the master section.
I'll spare you the nasty math, mainly because I care about it less than you. What this box does is combine your stems outside your DAW. You then take the stereo mix back in to your DAW or on to a 2-track recorder of some sort, where you then master it like normal. This doesn't make sense, does it? Well, first we need to talk about mixing to stems, rather than mixing everything to stereo. A graphic is in order:
So, you've got your group tracks. Now, the next phase of the operation assumes that you have an 8 (or more) channel soundcard. Rather than bussing all of those groups to your stereo output like normal, you'd buss Group 1 to outputs 1+2, Group 2 to outputs 3+4 and so on. You're left with 4 stereo sub-mixes rather than one. This next graphic illustrates how a summing mixer enters in to the picture:
So, as you can see, your four stems get summed outside the DAW. They are then returned to the DAW, where you will record them down to a stereo pair, which you can render like you would normally. Now, the major hiccup here is monitoring your stereo mix. This is where something like the Presonus Central Station comes in to the picture. In the next installment, we'll have more charts and diagrams and shit that explains in some detail more complicated setups. In the third and final installment, we'll round up all the currently available dedicated summing boxes, and go over their pros and cons.