Using EQ
Part 1 of my series of explanations of popular effects
An EQ or equalizer is an extremely powerful tool in the mixing process; probably every project I have ever done has included EQ somewhere in one or more of the effects chains. EQ is a tool for changing the frequency curve of a sound.
Of course, in order to get the EQ right for a mix, the best thing you can do is get your mic placement right to begin with, and your mic choice for that matter. If your mic is in a bad spot, EQ can only help you so much. Maybe you’re like me and you have room problems, or a small selection of mics, EQ can help to some degree in those areas. Even if your room, mic choice, and mic placement are perfect, there will often be times where EQ is still necessary just to fit that instrument into the mix. So on to the types of EQ and their controls
The there are 3 main types of EQ
Parametric – Only allows you to adjust a few bands, but has Q controls.
Graphic – Allows the adjustment of many bands, but does not have Q controls.
Paragraphic – blend between parametric and graphic, basically it is a graphic EQ with many bands in which you can control the Q of each band. Before software plug-ins became popular, paragraphic hardware EQ’s were rare due to size and cost. Now most software EQs are paragraphic because they are easier to use.
IK Multimedia Amplitube's Graphic and Parametric EQs. All other examples are shown using Izotope Ozone's paragraphic EQ
FILTERS
High-pass/Low-cut
This type of filter cuts frequencies below the frequency that you specify, or, it lets only frequencies above the frequency that you specify pass through. Basically, if you set a high-pass/low-cut filter at 200hz, then frequencies below 200hz will be turned down, frequencies above 200hz will remain unaltered.
This filter is often useful on things like vocals or acoustic guitar where lower frequencies may add too much boominess or are unnecessary to the mix and just add mud.
High-pass/Low-cut filter
Low-pass/high-cut
This filter is the opposite of the high-pass/low-cut filter. While that filter cuts low frequencies, a low-pass/high-cut filter removes unwanted high frequencies. I have found that I use this type of filter less frequently than its counterpart, but I have found it useful on harmonica, which can get shrieky on high notes.
High-cut/Low-pass
Bandpass
This filter is kind of a combination of a high-pass/low-cut and a low-pass/high-cut filter. It creates a sort of bell-shaped curve in the EQ, only allowing though a range of frequencies determined by the user.
This, along with a few other effects, can be handy if you are trying to create a megaphone effect on vocals (or any instrument really).
Bandpass
Notch
This filter is basically the opposite of a bandpass filter, it is used to cut a notch out of the frequency spectrum. These can be handy if a certain frequency just keeps honking out at you
Notch
CONTROLS
Q or Quality
The Q controls how wide or narrow the band of frequencies is that you are adjusting. I’ve also seen this referred to as bandwidth. The image of the notch filter above shows a narrow Q, below illustrates a wider Q.
Wide Q
Frequency-
This controls what frequency will be affected by the gain.
Gain-
This controls how much you boost or attenuate your chosen frequency.
Output gain-
As with many effects, the output gain controls the overall level of the signal coming out of the equalizer. Try to balance this with the level of the signal before it was equalized so you are able to compare the track with and without the effect.
EQ techniques
I’m no expert on EQ but here are a few techniques that I use frequently on frequencies. (haha)
-General rule of thumb: Cut narrow, boost wide.
-When EQing, do it in the context of the whole mix. Don’t solo the track and EQ it like that, what might sound bad soloed, may sound great in the mix and vice-versa.
-Try to boost frequencies that accentuate each instrument and cut those that are unnecessary or are clashing too much with other instruments.
-Parametric sweep
Perhaps the most important technique; Boost the gain way up on an EQ band with a very narrow Q. Be sure to put a limiter on your master bus when doing this, so as not to clip your speakers when boosting each band. Slowly move it across the frequency spectrum. As you do this, you will hear certain ‘bad’ frequencies pop out. You’ll probably know them when you hear them. When you find one, just turn the gain down appropriately on that band and repeat the process again with another band until you have removed all the problem frequencies.
This is a great way to carve out some nastiness in a track while maintaining richness and clarity. It can be a great alternative to using something like a low-cut/high-pass/high-cut/low-pas filter, which in some cases may remove valuable information that lies in what is being cut.
For example, say you have a song that is nothing but acoustic guitar and vocals. The guitar is a little too boomy, but you want it to sound rich and big because there is so little else in the mix. You could roll-off the low end, but that may leave the guitar sounding thin or weak. By just cutting narrow bands of boomy frequencies out of the low end you are able to maintain that big rich bold sound you wanted.
I mentioned the megaphone effect so I suppose I’ll include that here too.
Use a bandpass filter with a bandwidth somewhere around 600hz-5khz
Use a multiband compressor to boost and brickwall the midrange frequencies
If your compressor doesn’t saturate to distortion, add a fuzz or distortion plugin, maybe a saturation plug-in, play around with whatever you got
Add reverb and/or delay for space if you wish.
Wow, lots about EQ. I hadn’t anticipated writing so much, but there is a lot to talk about. And I could probably continue on, but here is some basic stuff that I think I understand well enough to explain. Hope it is useful to someone. Let me know if it was.
Until next week,
ONE
-the Attic Boy