Summing

Let’s face it, audio is quite subjective.  We trust many of our recordings to people who are considered to have “golden ears” even when we sometimes can’t hear the difference.  We don’t all have perfectly tuned rooms or perfect ears for that matter.  My reason for these statements is to preface a trend in mixing and recording – the use of a summing mixer.  My approach is conservative because of all the factors that can influence the audio path but whether you run a small home studio or a larger commercial facility, you should know a little about summing.

We can probably all agree that those large, expensive consoles sound pretty darn good when you put music through them.  Take one of your home recordings and play it back through one in a nice studio and I bet you’ll hear a difference – usually a good one.  The thought here is that a channel of audio, when put through an analog audio path (like the discrete audio paths found in those large consoles), will sound bigger and better when it’s blended with other audio channels through the master output on a recording console as opposed to a DAW.  In other words, the summing of all the channels of audio on a good console tends to yield mixdowns with nice separation and clarity.  DAWs all do that – they can render stereo mixes of multi-channel audio at high resolution so why bother with the console?  That’s what’s up for debate and where it gets subjective.

If you’re happy with your mixes then you can probably stop here.  Many of us small studio operators however are always looking for that next tool or technique that’ll really make our mixes shine and stand up next to the big-boy mixes coming off API, SSL or Neve consoles and the like.  Summing may be able to help but it’s up to your ears to tell if it works for you or not.  DAWs do the summing mathematically and the theory is that it’s not always efficient and different DAWs will produce slightly different results from the same source material.

To make use of the summing approach you need to have the ability to run outputs from your DAW to an external mixer (preferably a good analog console).  There are now many summing solutions on the market and many of them use an 8x2 matrix approach (8 inputs, 2 outputs).  The idea is that you’ll feed 4 stereo outputs from your DAW as busses into a summing mixer.  You utilize those busses by perhaps assigning all the vocals to one, drums to another, guitars to one and keys to one.  This is commonly known as stem mixing – 4 stereo mixes of your tracks, each containing particular elements or instrumentation.  These 4 stereo pairs are run into the 8 channels on the mixer.  The master output is then either recorded back into the DAW on a new stereo channel or to another mixdown device like the Alesis Masterlink or an analog tape recorder.  The goal is not to EQ or re-do the levels (though that’s an option if desired) but to take those 4 stems and blend them in the console to use the console’s summing instead of the DAW’s.  Another facet of external summing is that you can also monitor the stems/busses through your console or summing box while you record and mix.  This too has been touted by many as a difference maker in making good recordings and mixes. 

Now for the results.  Hmm, I can’t really give you any.  This is something that you’ll need to hear for yourself.  I’ve read about listening parties where 4 engineers have compared 4 different methods of summing in blind tests and came back with 4 different preferences as to which mix they liked best and why.  So does summing work?  I personally think that there’s something to it and have started to implement a summing solution in my own studio.  When I have some results for comparison I’ll let you know if I can hear the differences.  If you have the ability in your own studio to do external summing then give it a try.  You may be thrilled with the results or you may not hear any appreciable difference but at least it’s an avenue explored.  Let your own ears be the final judge.