Non-linear summing

[Otto Halmén]

When I saw that Airwindows released the new Console4 for free (and for both Windows and Mac) I thought I'd bring up the topic of non-linear summing. This is now, as far as I know, the only freeware non-linear summing plugin.

The idea of non-linear summing is simple. Apply a function to each sample on each track, mix them, and apply an inverse of that function to each sample on the mix bus. Think raising every sample to the power of two with an insert on each track and taking the square root of each sample on the master channel. (Note that actually squaring, mixing and then square rooting does not yield a good sound. I tried. Proper non-linear summing plugins use subtler and probably a lot more sophisticated functions.)

Whatever effect is has on the audio is, therefore, directly related to the mixing of multiple signals. This is supposed to simulate a certain aspect of analog mixing consoles.

The most important question is, of course: Does it sound good in an orchestral template?

I did an A/B test. This plugin has its own kind of ugly distortion if you drive it too hard, so I set the volume of each track so that the mix was a bit under breaking point. Besides being able to distort the audio in a way you haven't been able to before, I'm not sure what it does, exactly.

It kind of sounds slightly different in a couple places. The timbre of the trumpets sounds just a tiny bit smoother, and sometimes it feels like there's a small change in the attacks of the percussion.

Here's my first A/B test of Console4

Has anyone of you used non-linear summing plugins before? Possibly in an orchestral setting? What kind of difference did it make?

[Mattias Westlund]

I've never tried any summing stuff like this, as I don't have any particular interest in emulating the characteristics of analog. If I wanted distortion, hiss, bleed and flutter I wouldn't have moved to digital in the first place. Moreover, I've always had a strong suspicion that most developers of such things are snake oil peddlers and nothing more.

Comparing the two versions I hear saturation and loss of high end in the second one. That's the only really perceivable difference to my ears. First version sounds better to me.

So... how does this work? How many inputs does the summing plugin have?

[Otto Halmén]

It works by snapping Console4Channel at the end of each track, and Console4Buss at the beginning of the mix bus. Hence, it can be used on as many tracks as the DAW allows. The issue is that there's not supposed to be any processing between the plugins, including channel strip components such as volume and panning. All of that should come before the plugins. Therefore, projects with subgroups and nested sends may get a bit unwieldy. I, for one, had to create a whole bunch of extra aux channels just to get the routing right.

[Mattias Westlund]

Yikes, that does indeed sound messy for big and complex projects. Especially since, IMHO, you could probably get some pretty similar results from just using a tube/tape saturation plugin (and/or analog-flavored eq and compression) on the master bus

Please note that I'm not saying this plugin doesn't do anything useful, just that I'm not hearing it. So it might be my ears and/or listening environment.

[Otto Halmén]

That's what I do, anyway. In my current setup, Console4 takes up way too much CPU power to be useful for real-time tracking, and IGVI + Luftikus on the mix bus already gives me a reasonable amount of flavour.