1-The high pass
A high-pass filter can help to make your vocal tracks sound cleaner and less muddy in a mix. It will also remove any low-end rumble or noise that may have been picked up during recording. The goal is to remove unwanted low-end without compromising the tone of the vocal. Put on an EQ with a high-pass filter and play the vocal in the mix. Start the high-pass quite low, around 80Hz, and gradually move it up the frequency spectrum until you start to hear it making the vocal sound thinner. This will usually be somewhere between 120Hz – 200Hz. Once you hear it thinning out the vocal you know you’ve gone too far, so back it off a bit and that should be the sweet spot. If you’re not sure where to set it, just start with 100Hz.
2- The High Shelf
As a general rule of thumb, most vocals can benefit from a bit of a top end boost – it helps to ‘open them up’ and cut through the mix. To do this, we’re going to be using a high shelving filter. Usually, a subtle boost starting from around 6kHz – 12kHz will do the trick. The higher you start, the more subtle the effect will be. The lower you start the shelf, the brighter and more obvious the effect will be. If you just want to open up the vocal slightly and add a bit of ‘air’, try a 1dB – 3dB boost from about 12kHz. If the vocal is very dull and sounds like it’s got a blanket over it, you could try starting the high shelving filter from around as low as 4kHz – 5kHz.
The sweep is about finding frequency areas that don’t sound very good, and cutting these back to improve the vocal tone (if the vocal tone already sounds great, you don’t need to do this). It’s called ‘the sweep’ because we’re going to ‘sweep around’ (move around) the frequency spectrum to help us find any bad sounding frequency zones. Choose a peaking / bell-curve filter on your EQ and boost it up by about 10dBs. Now, starting at around 100Hz, slowly move it up the frequency spectrum as you listen out for any areas that sound particularly bad – sometimes it’ll have a ‘ringing resonance’ to it. Once you find the basic area, try cutting this back slightly to hear if it improves the sound. On some vocals you’ll hear a boomy, muddiness around the lower mids, 150Hz – 300Hz. Other vocals are very nasal around 800Hz – 1kHz. And occasionally, you’ll find a vocal may be too harsh around 2kHz – 3kHz.