How To Use A Mid Side EQ

Mid side is referring to the stereo field which is the placement of your sounds from left to right and front to back. This has to do with the whole concept of the stereo image. When a song is played, the listener’s speakers create the audio equivalent of a stage which is called the stereo image or stereo field. When you mix the song, you can set your instruments wherever you want on that imaginary stage. The mid refers to the mono signal which is the center of the mix. So, this is will be the audio at the center of the stage. To convert a stereo signal to mono you need to sum the left and right channels together. Because you are adding these channels together the audio that is present in both channels will be doubled in volume. However, the audio that is present in only one channel will be the same volume when converted to mono. That means that after conversion, all sounds that are more stereo, will be quieter. This is often expressed as “mid equals left + right channels.” Now you know what the mid is, what are the sides? As you may have guessed, the sides are all the stereo information in the audio other than any mono or center information. The sides of your audio are what give your music a wider and more spacious sound. To get the side information, we use the equation” side = left - right channels.”

So, what is mid side EQing? Mid side EQing is an EQ that separates the stereo field into mid and side so you can EQ the frequencies in the specific stereo fields separately, as opposed to a normal EQ which affects the entire sound in the entire stereo field. In my YouTube Video on mid, side EQing, I illustrate what mid side processing does by going into the mid side EQ and showing the audio effect of cutting and boosting in the middle and sides of the stereo field. You can hear the difference when you to boost the high frequencies of the mid or mono signal. Try this with your own equalizer settings. First, boost only the high frequencies in the mono signal, without any change in the high end of the sides of the stereo field. Then, cut out the high frequencies in the mid or mono part of the stereo field without changing the sides. You will able to hear the difference when the middle is bright and clear as compared to when you can hear the sides of the stereo image bright and crisp while the center sounds dull. After you’ve listened to the difference, try first boosting the high end of the sides of the sound, and then cutting the high end of the sides. You will be able to hear that when you do this, the middle part of the stereo image is untouched while only the sides are affected. To hear the affect on the sides of the stereo image even more clearly, try muting the mono part of the stereo field and then boosting and cutting the sides again. Experimenting like this with your own mid side EQing will show you what the boosting and removing of frequencies in the mid side of the stereo field sounds.

So, why would you use a mid side EQ instead of a regular EQ? Since a mid side EQ allows you to boost frequencies in separate parts of the stereo field separately, that is in the mono and the sides of the stereo image, it enables you to fit the elements in your mix more precisely and create more interest in the stereo field. This separate EQing of the parts of the stereo field can only be done with mid side processing. It cannot be done with a normal EQing.

Of course, you will continue to use normal EQing to fit elements together in your mix, sometimes this will cut or boost frequencies that you don’t want changed. For example, if two sounds are conflicting in the mix, and you use a normal EQ to fit them together, you will probably be cutting away frequencies to get them to fit together. Normal EQing may give you the sound you want. However, if the sound that you’re cutting away frequencies from only has conflicting frequencies in the mono part of the stereo field, using a normal EQ will result in cyou cutting away frequencies in the side channels that aren't conflicting in the mix. Doing this results in thinning out the sound. That is a situation where you should use a mid side EQ. Mid side EQing allows you to cut the problem frequencies in the exact part of the stereo image that they’re conflicting in and avoid thinning out the sound. Also, the ability to EQ areas of he stereo field separately, allows you to create an even greater sense of depth and width in your tracks.

To give you a better understanding of mid side EQing, I’m going to go over three common situations in which you should use a mid side EQ in your tracks.

Any time you want something to be a bit wider in the mix and to have more depth, you can use mid side EQing to accomplish this. For example, if you have a track with a main super saw (or any other synth) playing and this element is the main event of your song, then you want it to be wide in the stereo spread of the mix. To get this effect, you can use mid side EQ. First, solo the synth that is the main event. Remember that the sides of your mix give the stereo imaging. That means, the sides give the perception of a wide and spacious sounding mix. Also, you need to know that high frequencies are more directional, which means that our ears have a better understanding of where a high sound is in space than a low sound. So, to get that wide sound in your mix, you should go into your mid side EQ and boost the high frequencies in the sides of the mix. This will make the stereo information of the high end of the synth more present. Try adjusting the equalizer settings so that there is not too much poking out of the mix and it's giving the synth more width. To further accentuate the width of the main synth, you can also go into the mid channel and remove high frequencies which will accentuate the high frequencies on the sides that are directional. Doing this allows the listener to discern the sounds better in space. The result will be to create the depth and width that you want in your main synth.

The second common situation in you can use mid side EQing is to fit individual elements in your track together. For example, if you have a track where there are two basses layered up so which have a lot of conflicting frequencies in the low and mid-range, you can use mid side EQing to fit these elements together better. First you need to listen to the individual layers so you will know what to EQ. Suppose you have a mono bass which is only playing in the mono part of the stereo field and then you have your wide bass which is playing in the mid and sides of your mix. When I am using my EQ, I like to think about each individual sound and what function that sound plays in my mix. In this situation I would want the mid-range and low range of the mono bass to come through in the mix, because that will set a foundation for my track. That means, when I do my mid side EQing, I want the mid range present in the mono part of the stereo field. To achieve this, when I am cutting these elements to fit them together better, I'm going to be cutting away the mono part of the mid and low range where they are conflicting. This will allow the mono bass to shine through in my mix. I can only do this using a mid side EQ. A normal EQ won’t keep the mid and low range of the sides of this wide bass and I want to give a full sound. So, instead of using a normal EQ and EQng out the mid and the sides of the mid and low range, I use a mid side EQ and EQ out only the mid of the wide base. This will fit these elements together better and have them come through cleanly in the mix.

The first step if you were using the mid side EQ in this situation, would be to do EQ sweeping on the mono bass to find the most prominent frequencies where you hear a lot of power in the sound. Once you find these frequencies, you need to decide how much gain reduction to use. Adjust the equalizer controls in the midpart of the stereo field until you feel that the mono base is coming through a lot cleaner. Set the EQ there, then listen to the basses with and without the EQ so you can hear whether the mono bass is coming through as clean as you would like and there are no conflicting frequencies between the mono and wide bass. Doing this fits the elements together while leaving the mid and low end of the sides of the wide bass intact.

The third common situation in which you should use mid side EQing is to fit together groups of elements. This is similar to the second situation, except it requires working on a group of elements in the track rather than Individual elements. An example for this situation is if you have a track where the vocals are a little drowned out in the high and mid-range and some of the synths conflict with the vocals. If when you listen to the track you can hear that most of the vocal’s power is coming from the mono part of the stereo field (even if there is a reverb and delay on the vocal giving it volume in the sides of the mix) which is a common situation where producers use a mid side EQ. The goal is to go your group of synths and EQ out only the mid range which will allow the synths to continue filling out the sides of the mix. By leaving the synths in the side of the mix you will avoid thinning out the sound.

The first step in this situation is o find out what frequencies should be removed from the synths by doing EQ sweeping in the vocal and finding its prominent frequencies. Then using the mid side EQ you set the equalizer controls to boost the midpart of the vocal. Then, do more EQ sweeping as you listen to the synths so you know where to start cutting away frequencies. It’s important to listen as you do this because you don't want to cut away too much, just enough so the vocals aren’t poking through the mix. After adjusting your equalizer controls, listen to the track with the EQ off and then with the EQ on to hear the difference. Your goal is to make the vocals clearer in the mix, a little more up front and center, and also to tone back the conflicting frequencies.

Well that wraps up the discussion of the three most common situations for using mid side EQing in your mix. Try it on your tracks and I’m sure you’ll hear the difference!