I’ve been a live sound engineer for most of my life. I’ve seen a lot of strange things over that time. Once, I sodomized a taxidermied coyote with a mic stand in the line of duty. And yes… there was a microphone on the stand at the time. But, today it’s not my intent to talk about the strangest problems with live sound. Instead, I’d like to discuss the most common problem with live sound; mud.
Mud occurs when there are too many frequency sources in the low mid range. For example, a band could have a couple electric guitars, some male vocals, a snare drum and a keyboard all competing for the same audio spectrum. Often times this leads to escalating stage volume as each person demands more of themselves in the mix due to their difficulty hearing themselves. The end result can be very loud and muddy.
The best solution for the problem usually begins with arrangement. Two guitarists should be mindful of each other, choosing to play in different octaves using different voicings whenever possible. A keyboard player can easily overfill the low mid range if they’re not paying attention to the other midrange instruments. It’s important to “get in where you fit in” and to avoid stepping on another musicians toes.
Muddiness lives in the 200-500hz range. If this range is being boosted somewhere in the signal chain muddiness will increase. As a soundman I can control what comes out of the monitors and the front of house speakers but guitar amps and other backline gear is out of my control. An act or backline tech needs to keep this range in check if they want their stage mix to be optimal.
It is possible to go too far with it of course. “Scooping” the lower mids to an extreme will result in a brittle sounding mix. As with most adjustments to EQ in live sound, less is often more.
When you notice an instrument is starting to sound muddy in your mix cut 2-3db from about the 300hz range. It may be necessary play with the sweepable mids control until you find the exact frequency range causing the problem.
With multiple instruments contributing to the problem it sometimes helps to cut a different frequently from each of them allowing them each to sit in a slightly different spot in the audio spectrum. Remember, when you cut something with EQ it’s often helpful to boost the gain in a corresponding fashion as not to lose volume.
Adjusting the EQ on the monitor or front of house mix can also be helpful. I shy away from making drastic cuts to my front of house mix whenever possible but sometimes it’s the easiest solution. I find this to be especially true in smaller clubs where the stage volume is contributing to the overall sound.
An act and their live sound engineer need to work together if they are going to banish the mud from their mix. The act is responsible for arranging their music to cover a broad audio spectrum and for avoiding lower mid boosts with their backline gear. The audio engineer can then make selective cuts to the 200-500hz to clean up the mud the rest of the way.
A clear mix with each audio source sitting comfortably in it’s own audio spectrum is a pleasure to listen to. It’s easier for the act to perform when they can hear themselves clearly and the audience notices as well. Get the mud out of your mix and you will become an asset to your clients and to the fans.
I hope you find this article helpful, if you have any questions feel free to leave them in the comments below. Good luck!