QuadCurve EQ Demystified

If you’re a SONAR X1 user then you’ve probably already seen that the free SONAR X1d update has been released for all versions of SONAR X1. And if you’re a SONAR X1 Producer Expanded user, then you’ve probably already noticed that you’ve got a shiny, new EQ in the ProChannel called the QuadCurve EQ.

However, you might be wondering what exactly the deal is with the new EQ and and what the differences are in the four modes.

                Hybrid                           Pure                            E-Type                        G-Type

In a nutshell,  the QuadCurve EQ is exclusive to SONAR X1 Producer Expanded and is an updated and enhanced version of SONAR X1 Producer’s Gloss EQ. Both EQs share three common EQ modes while the QuadCurve EQ has a brand-new, fourth mode called Hybrid. The QuadCurve EQ also has an updated graphical user interface while two of its EQ modes have been renamed.

The Gloss EQ’s Modern mode is now called G-Type in the QuadCurve EQ while Vintage has been updated to E-Type. Pure mode, however, maintains its moniker across both EQs.

Nothing has changed in the DSP or sound quality of Modern/ G-Type and Vintage/ E-Type, so the mixes you’ve done with the Gloss EQ will sound exactly the same when opening a project in X1d with the QuadCurve EQ. We changed the names because we felt the new names are more specific and better represent the mode’s sonic characteristics, history, and lineage (more on that below).

Each of the four modes, G-Type, E-Type, Pure, and Hybrid, have different Gain/ Q dependencies. In other words, each mode’s curve behaves differently relative to the Q as the frequency is boost or cut.

Below is a look at each of the QuadCurve EQ’s four modes and how their unique Gain/ Q dependencies behave and sound. In each graph the Frequency is set to 1khz while the Q is set to 1.0. Level is shown above each graph.


1khz, Q 1.0              +6db                                            +12db                                          +18db

The QuadCurve’s G-Type mode is modeled after the behavior of the legendary British console EQ that was first introduced in the late 1980s. It has a moderate Gain/ Q dependency which means the Q automatically reduces with Gain, making the base of the EQ curve wider the more you boost or cut. This gives the EQ a warm, musical sound that is great for color and fill as you don’t need to change the Q setting as you boost or cut.

People often use this mode on vocals, instruments, and other sources that require tonal balance or color, but not necessarily surgical EQ like removing a ring from a tom or other notch filtering type tasks.


1khz, Q 1.0              +6db                                            +12db                                          +18db

E-Type models the classic British console EQ from the 1960s and 70s which has a more clinical sound than its younger G-Type brethren. This mode has minimal Gain/ Q dependency and is often described as sounding, ‘clean’ or sometimes even, ‘harsh’, as its Q stays relatively tight with moderate boosting and cutting.

This is great for certain types of music that require a clean or clinical sound, like metal and pop, or for doing relatively surgical EQ tasks like removing a ring from a kick or snare.


1khz, Q 1.0              +6db                                            +12db                                          +18db

The QuadCurve EQ’s Pure mode features high Gain/ Q dependency and is best described as, ‘smooth,’ and ‘gentle’. Because the base of its EQ curve stays the same no matter how much its boost or cut, its perfect for use on buses or as a mastering EQ. This is because when EQing a bus, or an entire mix, you want to add or subtract an overall tonal balance rather than perform a surgical type of boost or cut (which is best done on the track level).


1khz, Q 1.0      -12db                              -18db                               +6db                             +12db

Hybrid is an asymmetrical mode that’s a combination of minimal to moderate Gain/ Q dependency on boost and virtually no Gain/ Q dependency on cut. This allows for clean EQ on boost and extreme, surgical EQ on cut. In the picture above notice that the base of the EQ curves on boost are much wider than they are on cut.

This is arguably the perfect EQ for mixing drums and percussion because when boosting a drum you typically want to add EQ fill and tone, while cutting a drum you typically want to notch out a specific frequency like a nasty ring or conflicting tone.

Learn more about the QuadCurve EQ and SONAR X1d and other ProChannel modules.

Published by

Seth Perlstein [Cakewalk]

Galactic conqueror and wielder of SONAR knowledge.

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