How To Improve Mixes Using Better Summing

By the time you get to the stage of mixing down your project you will probably have spent countless hours (days, weeks, months, years?) trying to perfect it, but a common and hugely frustrating occurrence is that the Master Sums don’t sound how you wanted them to. Lackluster, flaccid, missing something. Call it what you will, these sonic imperfections can often be attributed to mixing imperfections, which can be the difference between a good track and an amazing track.

- This isn’t a perfect reality -

There is no magic bullet that will fix any mix. However, by identifying what is happening, why it happens and how to improve it, you can gain knowledge and insight into some often overlooked elements of the process and as a result have better sounding mixes.  

Understandably, this is quite a broad topic with a lot of variables in addition to the handful of different techniques that can be used in mixing workflow. There is a lot of ground to cover so I’ve tried to focus on just a few fundamentals and broken this discussion into two parts.

Part One (this article) is addressing summing imperfections and incorporating hardware into the summing process to aid in improving the quality of mixes.

 So without further adieu, what is up with...

Summing Imperfections

You can probably relate summing imperfections to that guy who ruins every party. Just like him, they can burst into the room that is your mix-down and make your digital bounce sound sadder than finding out someone just nicked your last brewski. Fortunately, with a bit of know-how, pesky summing imperfections can be corrected and prevented.

The concept of summing is a simple one: compiling all of your tracks/channels into a single (usually stereo) file that you can render into a final track. This process originally derived from analog mixing consoles, so when digital recording and mixing first came into fruition some differences became apparent.

Due to computational simplicity in the digital audio domain, there can often be overlaps in digital summing when audio frequencies and tones are turned into digital data. Our ears can naturally distinguish these frequencies as individual sound sources, but it is not uncommon for code-based data to interpret multiple sounds as one and the same. This can result in audio and frequency masking, which can create inferior final mixes.

Similar to how converting audio files at low sample rates can result in truncation distortion and create harsh sounding “sizzling” higher frequencies, glitches in summing can reduce width and depth of stereo imaging and corrode the musicality of a track.

Digital recording technology has evolved immensely since its dawning days, but these errors in digital coding as a result of digital summing can still be an issue if not properly addressed, and are particularly exacerbated by increasing the number of channels in the summing process. This is less of a problem for analog summing because the process is simply executed by adding the instantaneous signal voltages together; over the years, voltage rails for analog consoles have been significantly increased in capacity to improve capability and reduce faults.

A solution to digital summing imperfections can be found by taking tracks out of the digital domain and summing in the analog realm, which will also provide width, height and depth to the mix. This is not the only solution – there are other digital options, but unless you’re a highly experienced audio engineer, it can be difficult to get the same results.

A preferred consensus from many engineers and producers is to run tracks or to group busses though analog consoles or analog summing boxes. The analog signal can then be routed back to the source of the DAW for a highly effective way to seal the final mix from imperfections, in addition to obtaining sonic attributions from analog hardware if they are desired. Another benefit of using this approach is recalling parameter settings, which can be made very easily compared to a full console recall.

Let this not be a crutch or excuse for poor mixing; analog summing will not make bad mixes better. More proficiency will make bad mixes better and for this experience is needed, or else no one would bother learning the craft. There are plenty of professional mixing engineers who use digital summing and mix entirely in-the-box, as well as those who swear by the analog domain or prefer a combination of the two.

To tie off a rather complex issue as lamely as an overelaborated episode of The Simpsons, analog summing can do wonders for summing imperfections and it’s even better if an experienced mix engineer can run tracks through quality gear with precision and expertise. Any analog console can be used be used for summing, in addition to summing mixers and boxes.