Equalisers are found EVERYWHERE. They’re in your Spotify app, your car, embedded into your earphones - you can even choose to have an EQ curve on your browser if you so choose! With them being so commonplace, you could be fooled into thinking that the types of EQ available are well known, but this is simply untrue; why would they have any need to know, right?
Well, in the case of the everyday mixing or recording engineer and especially when mastering your own music, it's imperative that you know these 3 main EQ curves to better enhance your mixes and try to stop users interfering with your mix by adding their own when listening back.
Parametric EQ’s are by far the most common place. They’re the digital EQ’s found in all DAW’s by default and usually have a minimum of 6-8 bands switchable between shelf, bell, high-pass, low-pass,and sometimes Baxandall (which I’ll go into later). Here's the built in Logic X EQ that's a perfect example of an in-DAW option.
By definition, Parametric EQ’s can control the individual parameters of the unit: Amplitude, Frequency, and Q (bandwidth). They’re commonplace on for example, SSL Consoles which have various shapes to the curves depending on the type of console – differing mainly in shelve shape, but it’s difficult to hear the difference. These EQ’s are great for almost everything, super surgical, or super wide for broad moves across several frequencies. This EQ is ideal for mixing moves and can be used across the mix on almost everything without running into problems.
Known for the ‘Pultec Trick’ and loved by pro’s all over such as David Penso, Chris Lord Alge, and Andrew Scheps for a good reason. These old tech EQ’s have minimal controls, with a simple boost and attenuation for a high and low band, but these are different in shape and therefore give this EQ it’s beautiful sonic characteristic.
The high band is switchable usually between 3 or 4kHz, up to 16kHz, which for many including myself, is the most used sweet spot for the glossy top end lift it envelops, especially on bus tracks. This can then be attenuated at 3 fixed points; 20kHz for gentle smoothing of the top end, after boosting, 10kHz, or 5kHz for those more harsh or brittle sounding tracks - or simply to instil a lo-fi vibe in a creative way!
The low band is how this EQ is known for it’s Pultec trick, the low band is switchable between 20, 30, 60 and 100Hz with the attenuation fixed in position. Because the bands are so broad, the boost control is relatively muddy when in the upper ranges, so I’d recommend not boosting past 5 on the controls, and staying between 20Hz and 30Hz. Once you have a nice warm low end, dial in the
attenuation of the small dip in those muddy frequencies without sacrificing your new solid low-end. This trick is commonplace in bass masters, usually in the signal chain of a kick drum or bass guitar. It’s also a key component of Andrew Scheps’ parallel vocal chain technique for a vocal that will cut through any dense mix!
Baxandall curves are by far the most specialised in their use. First invented by Peter Baxandall in the 1950’s, they’re now traditionally used in HiFi systems all over. They’re a very wide, gentle sloping shelf, until the end of the spectrum with a sharper Q to push the amplitude of the curve up on the lowest or highest part of the spectrum. These are well loved by the mastering community due to the natural sound associated with them.
Most commonly used in mastering, these are like using a large brush on a canvas, so should be used sparingly. They can be found in your standard DAW EQ curve as mentioned earlier, but the best are those that are a set of fixed points and emulations of revered gear already used for years - such as the BAX EQ or Clarphonic from House of Kush Audio. Both of these have been tried and tested for years by pro’s all over and are very common in pro mastering houses. Both feature 4 to 5 fixed points at opposite ends of the spectrum, however, the BAX EQ has a cut at both ends to tighten the curves further.