EQ familiarisation

> Step by step 1. How to EQ with OverTone DSP AF2-10 CM

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EQ is an important tool for shaping sounds and, on the face of it, an EQ looks like a pretty simple device to use. But there are some key features that are worth explaining. Our EQ of choice for this is OverTone DSP AF2-10 CM, and if you want to follow step by step, grab the audio examples from FileSilo. 2

Much like any EQ, AF2-10 CM allows you to boost or cut frequencies. Because it’s display-based (frequency is the x-axis and gain the y-axis) you can simply grab a node, make changes and both see and hear the results. Here we’ve moved the green node up, which is boosting at 1.1kHz. 3

AF2-10 CM has four bands, and if you select Clear in the bottom right, you simply add the bands by clicking on the centre line of the display. What’s more, if at any time you want to remove all the settings but still keep the bands, simply select the Flat option. 4

Each of the bands can work in a number of ways and to change or select this, right-click on a node. You’ll find a list of options; simply grab the one you want. There are nine main options, but essentially three different types of filter — peak, shelving and high/low pass. 5

Load up some audio, add an instance of the plugin and try out the different shapes. Here we’re using our Beats Loop audio, and we’ve added a low shelf, boosting about 10dB at 141.3Hz. To A/B what you’ve done, activate the whole plugin bypass (EQ) button at the bottom. 6

Each filter type also has a width that’s set using the Q parameter. On AF2-10 CM, the Q parameter is adjusted using your mouse scroll wheel over the node. So, sticking with our previous shelving EQ, adjusting the Q changes the profile of this filter, as you can see. 7

Try adding a few more changes. Spot how our red band is narrower than the pink band as we’ve adjusted the Q setting. Also, to help A/B when making changes, you can actually bypass a single band by double-clicking on its node. We’ve done this with our pink band and the shading underneath has gone, indicating it’s off. 8

You may have spotted that there are five types of peak filter. Each has a slightly different profile and behaviour drawn from how different analogue filter designs work. Select the Asym option, then try a big boost and cut, say 10dB. You’ll see that the boost is a broad shape and the cut a more narrow shape. 9

Finally, it’s worth looking at the high and low-pass filters. These are great for removing unwanted frequencies and are most typically used to cut out low frequency rumble from recordings. Use them as a pair and you can create a reasonable, though not particularly steep, band-pass filter.