The easiest way to add clarity during a mastering session is to amplify the frequencies most often associated with clarity - 4kHz to 20kHz.
If you use a shelf filter you can gradually and subtly amplify these frequencies. Additionally, change the slope value to make this amplification sound natural or a little more aggressive.
If you use a mid-side equalizer, then amplify the side image’s high frequencies is a great option. It both adds clarity and expands the stereo image.
If you find that there is a particular group of high frequencies that should be boosted, combine this shelf with a bell filter, and amplify the bell by up to 2dB.
Aural Exciters are really interesting processors that came about in the mid-1970s. They’re fantastic at increasing the clarity of an instrument, an instrument bus, or a full mix if used correctly.
They work by finding the harmonics in a signal and amplifying them. Whereas distortion creates harmonics, exciters only amplify existing ones.
Low-order harmonics will make your master sound full, but high-order harmonics, or harmonics higher in frequency, will add a lot of clarity to your master.
Since this processor is designed more with mixing in mind, you’ll need to use it subtly, otherwise, the effect can easily become too aggressive and unpleasant.
All distortion is in one way or another harmonic distortion - but by controlling these harmonics, i.e. how loud they are and their order, we can greatly impact the timbre and tone of our masters.
Tube distortion will create lower order harmonics, usually, a second-order harmonic which will make your master sound full - but if you’re looking for clarity, you can emulate tape or transistor saturation to create high-order harmonics.
If you’re new to mastering, try Softube’s Saturation Knob and select the Keep High option. This will create more high-order harmonics than low, in turn creating an impressive and present high-frequency range. Also, it’s a free plugin, so it’s a good one to try out.
Be careful with this effect though, or it will become too aggressive.
Sometimes, a plugin combines a few effects that make it perfect for handling a particular problem. This is the case with Slate Digital’s new free plugin Fresh Air.
It combines 2 high-frequency shelves with 2 frequency-specific exciters to add a lot of detail and clarity to high frequencies.
This plugin works really well on individual instruments, but at lower levels can be used in a mastering chain.
Keep the value of the 2 dials below 10, and you’ll find that the highs and high-mids really begin to stick out in your master.
Use the output dial to compensate for any gain changes this might cause.
If you’re looking to add clarity to your master, but you want it to be a little more exciting than simply increasing the amplitude of the high-frequency range, try a multi-band expander.
With it, you can increase the amplitude of high frequencies in a dynamic way. In other words, the expansion will only occur when the signal is loud enough to cause the expansion, creating a dynamic relationship between amplitude and clarity.
This works really well if you have a particular instrument with high amplitude in the high range - like a high hat.
This way you can capture it, amplify it, and rework the dynamics and ADSR of the high frequencies on your master.
Transient shaping is a lot like expansion, but with an emphasis on capturing and amplify the transients to create greater detail. Because the majority of transient that exist in a mix are higher in frequency, the transient expansion adds a lot of clarity to your mix.
A plugin that I like to use for this is punctuated by Newfangled Audio. It breaks the signal into 26 bands and allows for each to independently amplify and expand the transients of each.
If you’re using this plugin when mastering, you’ll want to keep the amount to 10 percent or less - otherwise, you’ll most likely end up with clipping distortion.
Additionally, it’s best to shorten the transient length to a little less than the default.
Although amplifying high-frequencies is often used to add clarity, you can achieve a similar effect by attenuating low frequencies. Low frequencies are often very powerful, and easily mask or cover up high frequencies that would otherwise provide clarity in your master.
Usually, 200Hz to 500Hz is the area that will cause a master to lack clarity and sound unbalanced. Start by attenuating these with a bell filter with a wide bandwidth by 0.5 to 1dB. The adjust as needed and move the center frequency around until you find a good spot for it.
The frequency you choose will often correlate with where the high frequencies are being occupied.