Summing boxes
Analog summing boxes are simple. They take many inputs and sum them into a mono or stereo output. The thing that’s cool about them is that this is summing on the voltage level. That’s what make it analog of course. The audio inputs are different voltages being combined to a summing bus. This summing bus will then be connected to the outputs. It is not more complicated than anything else in audio. Summing boxes can change the perception of your sound. Within summing boxes you could have different circuits that your audio signals goes through first before it hits the outputs. Hear me my fellow audio people! Let’s talk about this.
What is in a Passive Summing box
-Resistors (to Increase voltage drops, impedance matching)
-Capacitors ( stop Direct current(DC) from messing with your signal, coupling to ground)
-Transformers (Step up signals or step down signals)
-Diodes (rejects signals from harming your circuit)
Why does all of this matter, who really cares about this?
Ultimately there is a different between digital summing and analog summing. The concept is the same however, it’s just the processing is different. As mentioned before analog has voltages being manipulated. In fact the more components your signal runs through the more characteristics its has on the output side. You have voltages being manipulated and ultimately phasing being changed, especially if you have transformers or reactive circuits in you summing.
Now digital summing does not hold the same effects. Within your daw whether it be Pro Tools, Cubase, Studio One or any other you have to realize that it’s a computer program that calculates. When you put music in your daw it is a series of 1s and 0s that are governed by sample rates and clock timers. This Daw that we all use in the digital age is absolutely perfect. It makes it very easy to mix and record sessions right at home. With out the need of having too much outboard gear. However I do not see these daws emulating the true nature of summing and what it does to your mix.
What do you actually hear Sir Justin, what do you mean by changing my perception?
Welp. When you listen to our celebrities and the music they release. You love the sound, you can hear each instrument each vocal well balanced. We call it a 3D audio image here at OutBox Sound. This image is not just attained by using a Daw but these high end engineers mix through out board gear to help get that 3D imagery. The stereo width is also much wider and give you the sense of immersion. When you just mix in the Box (only in your Daw), it’s is a struggle to get perfect isolation. For example mixing lead vocals. You really want to keep that vocal at a good level over the instrumental. I have found that it is 10 time more difficult to do this in the box, cause you need more processing like ducking and compression. Mixing in the box has a very narrow sound, it also feels like the music is being strangled. It does not give the sense of depth or freedom.
Once again through some analog gear in the mix like a summing box and you can perceive that isolation and depth a lot better.
How can I use this summing idea ?
Ok I’m not telling you to go buy equipment that is thousands of dollars. In the link below is a DIY summing box that is only resistor based. Try that out. If you want more fun check out the other tools we at outbox sound use.
Cheap and fun DIY Summing Box $50
https://www.diyrecordingequipment.com/products/sb2-16x2-passive-summing-mixer
D-Box by Dangerous
https://www.sweetwater.com/store/detail/DBox
If you have the interface to handle summing I suggest trying it out for a couple of songs and just see what can happen. Your ear is the thing that you must trust not my words.
Also you can listen to our mixing examples on our audio page.
Thanks for reading
Justin Hunter of Outbox Sound