In this Logic Pro X tutorial, Eli Krantzberg shows you how to use the Gain-Q Couple Strength settings that are available in the Channel EQ to apply different non-linear curves for cutting and boosting.
Channel EQ Magic
I just finished working on a big project that used a lot of Slate plug-ins. I was particularly impressed with the Custom Series Equalizer. It sounds like it uses different non-linear curves for cutting and for boosting. Plus, the width, or curve, changes depending on how much gain you are either applying or cutting. It is a very impressive EQ in that you can push the gain to their extreme ranges without getting extreme results. It is a very smooth and warm sounding EQ.
Clear, Smooth Focus
On one particular track (a subgroup of electric guitars actually) I got incredible results by boosting several of the EQ bands to the max in one instance of it and then cutting the exact same frequencies the same amount in another instance placed immediately after. Normally this wouldn’t yield particularly interesting results. But in this case, it was magic. It sounded like a soft, warm halo was created around the center frequencies of each band, bringing them into clear, smooth focus. The way it tapered the frequencies around the specified values was perfect.
Gain-Q Couple Strength
I got to thinking about how we can recreate something like this with Logic Pro X’s Channel EQ. I’ve always been a big fan of the Gain-Q Couple Strength settings available in the Channel EQ’s extended parameters. Basically, it tapers the slope, or width, of the Q by different amounts based on how much gain is being applied.
There are six settings available: light, medium, strong, asymmetrical light, asymmetrical medium, and asymmetrical strong. Each setting causes the shape of the curve to react uniquely to different gain amounts.
It’s important to understand that the curves are created with the setting that is active at the time you create the boosts and dips. You, therefore, need to change the Gain-Q Couple Strength setting before making EQ adjustments. If you change it afterward, you won’t see or hear any results.
I haven’t gone through every permutation of pairing them in separate instances, but I did get some interesting, smooth, and musical sounding results with what I tried.
Audio Example 1
In these audio examples, I am using a sixteen bar groove with piano, bass, drums, and pad. I have separated the first half and second half onto separate tracks. The first eight bars are unaffected. The second eight bars have some EQ cuts and boosts applied. One instance of Channel EQ boosts or cuts with a specific Gain-Q Couple Strength setting, and then another does the opposite boost or cut with the same Q value and either the same or different Gain-Q Couple strength setting.
The first example uses the asymmetrical light Gain-Q coupling strength setting on both instances of the Channel EQ. The asymmetrical settings apply different non-linear curves to boosts and cuts. Here I am cutting 4Khz by 24 dB with a Q setting of 2.00 in the first EQ. The second EQ is then boosting the same frequency by the same amount using the same Q setting. The result is a nice smooth, focused boost around the center frequency that results from the different curves being applied.
Audio Example 2
This second example is cutting 400 Hz by 24 dB with a 0.60 Q setting and 800 Hz by 24 dB with a 0.71 Q setting using the asymmetrical light weighting. It is then followed by boosts at the same frequencies by the same amounts with the same Q settings, using the asymmetrical strong setting.
Audio Example 3
This example is using the asymmetrical strong setting on both instances of the Channel EQ. The first is boosting 800 Hz by 24 dB at a 1.10 Q setting. The second is cutting the same frequency the same amount using the same Q value. There is a pronounced change in the mid range that would be hard to achieve using a conventional single EQ.
Audio Example 4
In this last example, I am using the Light setting on the first EQ and the asymmetrical strong on the second. In the first instance, 500 Hz is cut by 8 dB, and 1200 Hz is boosted by 9 dB. The opposite is applied in the second instance.
It is worthwhile experimenting with this type of approach on all kinds of tracks including instruments, vocals, subgroups, etc. The non-linear curves of the asymmetrical settings yield particularly interesting results.
Have fun and happy EQ’ing with Channel EQ in Logic Pro X!