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FilterBank – Peak / Slope / Dip

The McDSP FilterBank v6 plug-in is a collection of 3 different EQ and filter configurations. Of these configurations, the E606 has an unique shelving EQ control set called Peak, Slope and Dip. These controls allow the user to customize the shelving EQ in a way only previously available to the EQ designers.

This issue focuses on the shelving EQ Peak, Slope, and Dip (PSD) control set and how they can be used in audio production.

Peak Slope and Dip Basics

Peak is the over shoot in the boost/cut portion of the shelving EQ frequency response. Peak is useful in adding ‘punch’ to the shelving EQ. A little bit of overshoot in the shelved band really helps the effect of the shelving EQ come through a mix. A judicious amount of Peak might offset the need for more shelving gain, and can allow the user to combine a shelf and nearly parametric response into a single band of EQ.

low_shelf
Dip is the under shoot in the non-boost/cut (i.e. the flat unaffected portion) of the shelving EQ frequency response. Dip works well to mask away the non-shelved portion of the frequency spectrum just above a low shelf boost (or just below a high shelf boost). As you increase the presence of some frequencies, it’s a good idea to reduce the amount of signal content just above/below the shelving response. This allows you to boost less because you are also cutting away some portion of the frequency spectrum – almost like an intelligent EQ!

Slope is the transition between the shelved and non-shelved portion of the frequency response. A more gradual Slope setting (50% or less) gives a smoother response – nice for boosting the high end of a piano track. Steeper Slope settings (75% and greater) provide a tighter response – good for bringing out kick drums or hi-hats. Note that the effect of the Peak and Dip controls is reduced as the Slope becomes more gradual. Peak and Dip have no effect on the shelving EQ shape when the Slope control is at its minimum setting (0%).

Peak Slope and Dip Applications

FilterBank is still, nearly 8 years after its release, the only EQ in hardware of software to offer the user complete control over the basic design elements of any shelving EQ with its unique Peak, Slope, and Dip controls. What does this mean for audio production? Here are some examples.

Kick and Snare separation

Typical music styles call for a good ‘thud’ from the kick drum. A good solution for such sounds is a low shelf EQ. But as the kick is being boosted, the snare sound should not get the same treatment. For that matter, the ‘thud’ of the kick should not compete with the ‘thwack’ of the snare. Using the low shelf, the kick is boosted for a nice ‘thud’.

Original Kick and Snare Example

Hi-Hat, Cymbals

The Peak, Slope, and Dip controls are not only good for getting surgical as in the above example. These controls can allow the same shelving EQ gain and frequency settings to have a variety of tones. In the examples below the same drum kit is processed with some high shelf EQ, but with different variations of Peak, Slope, and Dip.

Original Hi-Hat, Cymbals Example

Classical Guitar Air

Some folks refer to the high shelf boost as adding ‘air’ to a track. As shown with the Hi-hat and Cymbals example above, a variety of tones are obtained using the Peak, Slope, and Dip controls in FilterBank.

Original Guitar Example

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