What is a Passive Summing Mixer and how do I use it?
Most of us with project studios or small recording studios in our homes have probably gone through the same equipment scenarios, better microphones, preamps, software, plugins, countless upgrades in our computers, but we are still missing that polished, subtle end sound.
If you are like me, putting a studio together on a budget does not leave enough room to buy an $800.00 or more summing mixer. This is where the line of small passive summing mixers from Unit Audio comes in. I designed and built these passive mixers from a tested schematic I found, of course, on the Internet. These mixers are to be used with 8 or 16 channel converters. Again if you are like many of us out there you may have a multi- channel converter and only use the inputs for tracking and maybe two outputs for playback. This leaves a lot of unused outputs. These outputs can run through the summing mixers balanced line inputs and then out of the two summing mixers balanced microphone level outputs into a microphone preamp for increased gain. You then run out of your preamp back into two channels of your DAW for your stereo mix.
Pretty simple. The resulting sound is subtle, but definitely better. The stereo separation is better; the bass sounds are tighter and more defined. These mixers require no power to operate, no batteries, no wall connections. There is no AC line noise; they are simply transparent, and now at an affordable price.
Great article on Summing and Mixing from the December 2011 Issue of Mix Magazine
Signal Path Diagram
This diagram shows where the summing mixer fits in the signal path.