High Pass Filtering (abbreviated HP): is used to remove unwanted low frequencies. It’s something you’ll use on virtually every track in your productions; especially because of the rule of 300 we just discussed.
Low Pass Filtering (abbreviated LP): is the opposite of high pass filtering. Generally low passing is used to remove unwanted high frequencies aggressively.
Cutting/Boosting (aka Peak Filtering): is when you take a bell shaped filter and use it to either subtract or add frequencies to a selected range.
Shelving Filters: are the ultimate broad strokes tool. I look at shelving in terms of whether I want to make something Brighter/Darker or Thicker/Thinner.
With a high-shelving filter set at 1khz or higher, I can easily make something Brighter or Darker sounding.
With a low-shelving filter set at 1khz or less, I can effortlessly make an instrument Thicker or Thinner sounding.
Unfortunately, the ease, effectiveness and power of these filters, cause them to be one of the most overlooked tools at a mixers disposal.
Q: is best understood as a way to adjust the sharpness of EQ curve. Different curves will produce different sounds. An interesting behavior is that sharper curves tend to be less transparent when boosting than their cutting variants.