Can a Y cable be used to plug two microphones into a single input?

Answer: Due to improper impedance matching, using a Y cable to plug two sources, such as microphones, into a single input is not a recommended practice. In some situations this may “get the job done,” but too often it will lead to impedance mismatches, ground loops, and buzzes that will ruin otherwise good sounding signals. While ideal situations allow for every microphone source to have its own input on a mixer for maximum control, tools such as the Audio-Technica AT8681 UniMix® allow the user to easily plug in any two microphones and properly sum the signals to a single output. The AT8681 is similar to a small mixer which can be used in-line when the number of microphone inputs on a mixer is limited. The Audio-Technica UniMix can be used with Audio-Technica dynamic and condenser microphones as it will pass phantom voltage on to the microphones. There is also a balance control on the surface of the UniMix which allows the user to set a subtle volume variance between the two inputs. This can be helpful, for instance, to drummers who have limited inputs on the mixer; they can plug two rack-mounted tom-tom drum microphones, such as the ATM350, into a UniMix and use a single “Rack Toms” input on the mixer. The AT8681 UniMix is also a popular tool for churches that are installing hanging choir microphones and, again, are limited by the number of inputs on the mixer. Two choir microphones, such as the U853R, can be plugged into a UniMix and use a single “Choir Mics” input on the mixer. Again, while Y cables are not recommended for summing signals, they can be used for splitting a signal. A common scenario for this is when two recording devices are needed to capture the same signal. A Y cable can feed from a single stereo output on the mixer and split the signal to two different recording inputs. Hopefully this post has convinced you of the value of having the AT8681 UniMix on hand to help in a situation that requires proper summing of signals. But if you have any further questions, feel free to reach out to our Audio Solutions Department for personal assistance. We’re here to help!