How to Use Dynamic EQ in Mastering

Tips & Tutorials  |  November 6, 2014

This blog post has been edited from its original format; some references have been changed to reflect Ozone 7.

A dynamic EQ is a powerful tool that combines the precision of an equalizer with the musical ballistics of a compressor.

Available in both the standard and Advanced versions of Ozone, the powerful Dynamic EQ module truly lives and breathes with your audio. In this blog post, we'll define Dynamic EQ and illustrate ways to incorporate it into your mastering workflow:

The Difference Between EQs and Compressors

An equalizer is a linear processor, meaning it processes continuously independent of your audio. A compressor, however, is non-linear, reacting to both your input signal (relative to a threshold) and the compressor's attack and release ballistics.

To put it another way: An EQ consistently cuts and boosts particular frequencies throughout a song, while a compressor dynamically affects the levels of all frequencies throughout a song.

Multiband compressors have the added ability to dynamically affect the levels of specific frequency ranges using crossovers. Dynamic EQs utilize this concept, but replace crossover filters with traditional EQ filter shapes. The result? Unprecedented control over the dynamics of particular frequencies of your mix.

The Dynamic EQ interface allows you to adjust the frequency, gain, and bandwidth of a filter, with additional controls common in compressors like threshold, attack, and release. This combination lets you fine-tune the ballistics of the processing to best suit your audio. The underlying logic informs the boost or cut of the EQ filter, so that it responds to your audio dynamically in a more musical way than a static EQ.

Common Use Cases for Dynamic EQ

Here are a few common use cases that come up during mastering, with instructions on how to address them using traditional tools as well as a dynamic EQ:

Too-High Hi-Hat

Often, the hi-hat can sound slightly aggressive and overshadow some of the subtleties of the mix. Using traditional tools, you could use an EQ to insert a notch filter to cut somewhere around 5 k and adjust the Q (width of the band) appropriately. This lets you attenuate the hi-hat slightly; however, the more you reduce it, the more you're cutting those frequencies across the track—and thus taking some presence from the song.

A multiband compressor could also be used to dynamically process a frequency range similar to that of the hi-hat. So while you're now only attenuating frequencies while the hi-hat is active, you're still processing a much wider range of frequencies because of the crossover filter.

Dynamic EQ provides an ideal solution. First insert a notch filter at the same frequency as in the EQ example. Then use some of the compressor settings from the multiband compressor example. Now, you can precisely affect only the frequencies where the hi-hat resides, cutting with this filter dynamically as the hi-hat is active. This solution is transparent because of its deep control in both frequency and time.

Subtle Shine

Sometimes a mix lacks a certain brightness or shine that needs to be unveiled during mastering. A wealth of EQs promise to deliver this top end or "air" transparently with subtle filter shapes and analog phase characteristics. However, a common artifact of boosting these frequencies with an EQ filter is that the continuous boosting in this range leaves a mix sounding a bit harsh or fatiguing to the ear. You may end up having to compromise between giving the boost the mix it needs in this range and avoiding these artifacts.

With a dynamic EQ however, you can boost more aggressively without overloading the listener. Use a shelf filter with a gentle shape to ease into the top end. Then dial in some dynamic settings so the filter is able to adapt to the song, backing off slightly as elements like cymbals and snares emerge. You can boost the top end of your song beyond where a static EQ filter would allow, while not introducing a harshness to your master.

Unique Features of Dynamic EQ

Inverse Mode

In the previous examples, the Dynamic EQ acted like a multiband compressor: As audio exceeds the threshold, boosts and cuts are reduced, thus compressing the dynamic range of the affected frequencies. However, you can also flip this logic so that the filters respond more like an expander. In inverse mode, boosts and cuts occur as signals exceed the threshold increasing them the further they do.

If you wanted to bring out the snare in a mix, you could adjust a filter to boost at the appropriate frequency and set the dynamic settings to respond to the level of the snare hits. Now, the boosting filter will only activate when the snare is present, thus expanding the dynamic range of these frequencies. (Conversely, a cutting filter in the same scenario would only attenuate these frequencies when the snare wasn't present, acting much like a gate.)

Static Gain Offsets

An additional feature you'll find on many dynamic EQs is the ability to boost and cut gain both statically and dynamically with the given filters. As dynamic EQs often share many paradigms of EQs and are used in similar ways, it is sometimes useful to make a more traditional boost or cut with a filter as well as dynamically controlled boosts and cuts to ensure certain results.

For example, if you're looking to boost the top end of your mix as in the Subtle Shine example above, you may want to ensure that the shelf filter is continuously or statically boosting 1dB and dynamically boosting between 1 and 3 dB. These static gain offsets give you much greater control over how dynamic filters behave.

What to expect in Ozone

Dynamic EQ is a module available in both the standard and Advanced versions of Ozone 7. In addition to a curated workflow and modern user interface, Ozone features new updates and enhancements that will enable you to make the most of Dynamic EQ in your mastering workflow.

Smooth and clean UX

Ozone benefits from many of the familiar workflow advantages found in Ozone's Equalizer and Dynamics modules. The Equalizer portion features freely zoomable and scrollable gain and frequency spectrums, a spectrum analyzer, and Ozone's popular alt-solo frequency auditioning feature. The Dynamic portion features a Threshold Meter for adjusting threshold relative to input, monitoring for gain boost/cut, and a graphic Transfer Curve Meter.

Linear/Minimum Phase Processing

Most Dynamic EQs only offer minimum-phase, analog-style filters. Ozone's Dynamic EQ is the first plug-in to offer both minimum as well as truly linear-phase digital filters. Both styles of filters have their own strengths and are appropriate for certain situations.

Minimum-phase, analog-style filters exhibit a characteristic shift in phase response that has an often pleasant transient smearing effect, often described as sounding less harsh. Linear-phase filters do not add phase-shifting artifacts to your audio, and thus are popular for more surgical changes to limited frequencies. The Hi-Hat example above would be a great situation to utilize linear-phase digital filters.

Baxandall Filters

Both Ozone's EQ and Dynamic EQ feature Baxandall bass and treble filters, renowned for their ability to transparently boost low and high end. These filters are actually shelf filters, but appear to rise indefinitely because of their wide Q, which puts the shelf's shoulder outside of the range of hearing.

This gentle slope is especially popular for mastering because it can have a profound influence on the sound of your mix without drastically coloring the sound. Ozone is the first hardware or software product to add dynamic behavior to Baxandall filters, giving an entirely new dimension of control to this classic EQ model.

Prop Q

Both Ozone's EQ and Dynamic EQ also feature proportionate Q filters similar to those popularized in API hardware EQs designed in the '60s. These filters narrow the Q proportionately as gain is boosted and cut along a complementary shape as you sculpt your sound.

Unlike original designs, Ozone's proportionate Q filters allow for manual adjustment of Q values that will then scale proportionately as you adjust gain. These filters are particularly useful in Ozone's Dynamic EQ because as gain is dynamically adapting to your audio, the filter's Q is simultaneously adapting to gain values, creating a pleasant-sounding shape.

Auto Attack and Release Scaling

Ozone's Dynamic EQ interface is intuitive and easy to set up, due to its streamlined design and forward-thinking features. For example, the four-band nodes set by default in the Dynamic EQ have carefully set attack and release times by frequency, so that you can immediately begin making dynamic boosts and cuts. The Auto-scale feature allows you to adjust these nodes across the frequency spectrum, while maintaining relative attack and release times that are appropriate at various frequencies. In Auto-scale mode, you're still able to enter your own values and have them scaled across the frequency spectrum as you readjust nodes.

Although we've provided some specific use cases, dynamic EQs are beneficial any time you're looking to process your audio transparently—in other words, you're looking to solve a problem or achieve an effect in a way that the processing has no artifacts and is unperceivable to the listener. We hope you've found these guidelines useful, and we encourage you to fully explore the capabilities of a dynamic EQ yourself.

Elevate a good-sounding mix to a professional-sounding master with Ozone. Try Ozone Advanced for yourself—download the free, 10-day trial today.

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