Summing Two Mic Signals


One of my most popular articles has been The Mono Summing Cable that No One Makes. I’ve been contacted by more readers regarding that article than probably any other that I’ve written. That article details why it’s a bad idea to use a regular Y-cable or TRS-to-TS cable to sum two (usually stereo left & right) line-level signals to mono by simply shorting the outputs together. It’s ok to use such a cable for SPLITTING a signal, but not for COMBINING or SUMMING two signals. That being said, it can work ok on some devices, but on others it can cause distortion, weird phasing artifacts, and possibly even damage the outputs of your gear. However, combining the outputs of two dynamic microphones is a different story, and in some applications it’s ok to do so with a regular XLR Y-cable, as we will soon see. (more…)