Place a high-frequency shelf above the region already EQ'd to avoid pulling energy back down

When stacking EQ bands in mastering (e.g. a broad mid-range cut already applied below 5 kHz), a subsequent high-frequency shelf must be set with its turnover frequency above the existing cut’s reach. Setting the shelf turnover at 4–5 kHz when a notch or dip is already active there will cause the shelf to partially undo the previous cut. Starting the shelf higher (e.g. 7 kHz+) targets the true high-frequency air without interaction with the mid-range processing, achieving the intended ‘clarity without sibilance’ result. Adding a narrow bell filter to suppress sibilance within the shelf’s affected range is a common refinement technique.

Examples

You have applied a broad dip at 2.5 kHz to reduce nasality. Now you want to add air above 7 kHz. Set the shelf turnover at 7 kHz (not 4 kHz — that would pull up the 4–7 kHz region already shaped). Stack a narrow bell at ~8 kHz if sibilance increases.

Assessment

You have a broad HPF shelving cut from 300 Hz downward. You now add a high-frequency shelf starting at 3 kHz for air. What unexpected interaction might occur in the 300 Hz–3 kHz region? How would you correct it?