Analog Summing Mixer - coinmuki/summingmixer GitHub Wiki

What is the analog summing mixer?

A summing mixer is analog hardware for turning multitracks into stereo.

analog summing mixer

WHAT DOES AN AUDIO MIXER DO?

While a digital system rounds off all values for level, pan, eq-ing and compression, the analog summing technique operates with an infinitely high resolution, causing no rounding errors or digital distortions. The analog domain offers a number of great advantages compared to the simple “DAW bounce-function”.

Why analog summing mixer? Summing Mixer is simply combining DAW, Synth, or Drum machine output signals. The idea of a summing mixer is that you feed it multiple analogue audio signals, eg. outputs of your audio interface, synth or drum machines which are then combined (i.e. summed) in the analogue domain.

What exactly does a summing mixer?

Beside of combining signals, It provides Headroom - buffer safe zone for harmonics, transients or loud sounds without risking clipping, which result a more dynamic open and wide, depth 3D sound, just like the good old analog days. Read more on Vintage Maker Summing Mixer

Basically, instead of having your tracks merged digitally into a stereo mix in your DAW, you run each track individually out to the analog summing mixer and do it all there, then bring it back into your DAW

Analogue summing boxes have their uses beyond simply combining (sum) signals.

neumann summing mixer

Features like Mono option per channel for mono instruments like kick bass, or Channel Insert and master‑bus insert send return points, or Multi Master Insert Send Return for different externals can be extremely useful, as they provide an easy way to incorporate outboard hardware (EQs, compressors and the like) into your rig.

multi master insert send return chain

Documentation: https://vintagemaker.net/documentation/

Warming up your digital mixes

Analogue summing is proving a popular route for 'warming up' digital mixes.

Higher headroom, better depth and separation, better glue, ability to insert analog processing across, individual tracks, two or more busses...coloring or non coloring your tracks/stems/buses by DAW instrument or preamp inputs or high end line amps of different flavors...

Coloring or not coloring that is the question ...

Well, you can use a really warm tube amp for sound colour, or a really transparent amp for non coloring sound, that's your choice, and depend of your audio material.

btw - add an EQ for coloring / adding tone can massively redefine the tone of mix, and sounds really cool..:)

What is the Headroom?

Headroom is the point “the safe place” where your transients are not damaged.

audio summing mixer analog vs digital headroom

Headroom is how much room has your audio signal has before it starts to get compressed and distorted. It provides buffer zone for harmonics, transients or loud sounds without risking clipping, which result a more dynamic open and wide, depth 3D sound.

It provides space for Gentle Harmonic Distortion (harmonic and non‑harmonic distortions – analog nonlinearities)

Why summing mixer have gain loss?

The passive summing network have summing resistor placed between each channel input and output. This resistor (Vishay Dale) provides load isolation and improves channel to channel isolation.

summing mixer resistor network

The gain make-up amplifier like an External amp - your DAW mic preamp or line amp or Internal Lawo Filtek or Neumann which follows the buss is equal to the loss across each summing resistor. Since the voltage gain of the amplifier and the signal loss across the summing resistor compensates (cancel each other), the gain across the summing buss and amplifier is 1 or unity gain.

You can customize your desired summing setup on: https://vintagemaker.net/contact/#customorder

Okey, that's great but how it works - How to hit the analog harmonic distortion ?

Harmonic Distortion - The colour factor

Simply boost up your DAW output Level (master fader) – and you get some “nice” distortion because you’re pushing the summing passive side quite a bit over its nominal level.

You can hit the DA converters with hot signals from the DAW (hotter than you would have to do if ITB), depending on how much you like to drive your summing box. Let's say you are going out at full blast (gain) and drive the summing mixer (passive side) at its maximum.

On the return - master main rec side you can lower the level of the summed signal that much that you need to make it a converter friendly signal.