How to Mix and Master with EQ – 10 Equalizer Modes – Part Six - CDSoundMaster.com

Audio Recording with Equalizers – 10 Equalizer Modes – Part Six – Fixed “Q” width versus Variable “Q” width EQ

What EQ Mode is right for the job? Should you use an Equalizer that has fixed Frequency positions or one that is freely selectable? Should you use an EQ that can switch between various types of filters, or has a limited, but well chosen, set of precise settings? Do you want to work within a system of choices that always works well but also helps you to place your signature on your sound, or do you want complete flexibility to make independent choices at every turn, with the potential that many different types of music have an excellent result with an indistinguishable trademark in your artistic choices?

There is no single correct answer to these questions. It is just as justifiable to mix and master with an artistic touch that is complimentary and well-suited to each mix that also gives a nod to your personal style as it is to work with absolute precision and surgical care, letting nothing but the artist's best efforts shine through, never showing favor to one adjustment over another from song to song, album to album. These choices are central to the equipment that will serve us best. Equalizers that have a Fixed “Q” width are not necessarily as limiting to a person's options as one might think. A Fixed “Q” Equalizer may also have Fixed Frequencies, or the Frequencies may be fully adjustable from one range to another. There are no set rules from one EQ type to the next as to whether they must have an adjustable “Q” width. Not only does it make a difference if the “Q” can be adjusted or not, but for a Fixed EQ, we will make decisions based on just how wide the “Q” is set. Typically, “Q” has little significance when an EQ has multiple settings in its high and low Shelf settings. A Shelf setting typically will reach all the way to the end of the Spectrum.

Normally, when an EQ has a Fixed “Q” width, the “Q” is wide enough to affect the full width between one point and the next, with a smooth curve depth, meaning that the top of the mountain is rounded off to keep Gain adjustments smooth. At its deepest or steepest Gain, it will narrow steadily but still remain a smoother transition than if it were adjustable to a narrower “Q”. In very rare exceptions, an EQ may be marked at a wider “Q” than others.

An example is the NSEQ-2, which has a very wide interpretation of “Q” width. Even though it is marked at standard options, it is extremely smooth, and wide. Even at its narrowest setting, which is incredibly useful for mixing and mastering, it is not as sharp and narrow as an EQ like the Sontec, or even more the Amek 9098. We tend to think of a Variable “Q” as being the most flexible, and in most ways this is true. If the Frequency and the “Q” width are both Variable, then we can assume that any Frequency within the marked range can be broadly the center point that is adjusted, or can be sharply targeted for pinpoint removal. With Variable “Q” width, you have a bit more to learn about your EQ and its range of personality.

You may not find yourself using the exact same settings as often and for as many similar routines, so I always recommend taking time to learn the sound of your equipment, whether real or virtual. Load up sounds, songs, or tracks as “test” tracks that you are familiar with. Before you use an EQ that has tons of freely selectable positions, test it out with a lot of care. How does the sound change from wider “Q” to narrow “Q”? Does it sounds very similar or does it go from very smooth to extremely precise. Some EQ's increase a great deal in Gain the more narrow the “Q” selected. You may be used to using something at a medium “Q” at 5dB for boosting vocals or scooping guitars, and then you run into a place where there is unwanted resonance on a similar

Frequency; not an artistic decision but a corrective issue that needs attention. That 5dB is likely to narrow at the start of the slope in a similar fashion to the medium “Q” you are used to, but as it often sharpens to a point at higher Gain settings, it reaches much more signal increase or decrease, and you may be removing more than anticipated. It is not as easy to design the perfect Variable “Q” width EQ as one might think. The sonic results of one exact shape to the next is amazingly different. Narrow “Q” is good to have in some form, since it is hard to reduce serious trouble areas without a good sharp point that goes into deep Gain. This is not an easy task in analog or digital form. I can speak to this, as I was personally not satisfied with any result, analog or other, for extreme surgical EQ, so I set out to design my own. I created my Mastering Suite Equalizer that uses my own process that I created specifically for addressing surgical EQ for mastering music at 44.1kHz. The Amek 9098 is an extremely close second to having some of the most incredible EQ shapes, including very sharp narrow “Q” that works well, especially for tricky mixing but also in some Mastering scenarios. A fairly close third would have to be the Sontec and then the GML, which are both good enough to be desert island EQ's.

In any case, when you reach for a narrow “Q” width, listen for what else is getting removed from the signal and not just the part that needs to go. Also, listen for any resonance or strange artifacts coming from sympathetic Frequencies. My final recommendation to you when using an EQ that has Variable “Q” width is to make use of the settings that sit between typical “Q” widths. Namely, you have EQ's that contain typical fixed “Q” and you have EQ's that contain wider than normal “Q” width, and you have Variable “Q” that can supply the narrow band needed to tricky audio surgery. But, those settings somewhere in between the widest setting and regular setting are not found as often in standard tracking, mixing, and bus EQ's, as is the case with that range between mid “Q” and narrowest. Listen to these settings and become familiar with them, and train your ears to send a signal to your mind, so as to remember what affect these settings have on the audio signal. These settings will have their moments to come in handy.

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How to Mix and Master with EQ – 10 Equalizer Modes – Part Five - CDSoundMaster.com

Audio Recording with Equalizers – 10 Equalizer Modes – Part Five – Clean or Colorful EQ

This may seem like a strange choice for a topic on EQ modes. Deciding on a Mode to work with regarding EQ is a decision of how the sound is being adjusted, what affect it will have in the entire range of Frequencies, whether the slope is steep or narrow, gradual or sharp, among many other factors. The design of the EQ itself is a major factor in how the EQ reacts, and though there are many EQ's that share similar design and feature sets, the actual sonic results can be very different based solely on whether it leans more towards a clean or colorful electronic design. When these devices are emulated, their software equivalents will follow similar results.

A good example of how the electronic signal path affects how the same Mode settings are affected is the Millennia Media NSEQ-2 Twin Topology EQ. It allows the user to switch between the highest quality high voltage vacuum tube signal path or the highest quality op-amp solid state signal path that the electronics world has to offer. Using the exact same settings, the way that the Millennia Media NSEQ-2 renders the shape of the exact same setting in Solid State Mode is different than that of its identical setting in Vacuum Tube Mode. One will have a sharper result where the other will be slightly rounder. Both would be considered very precise, but that isn't the only result. Both options are extremely clean, but the subtle harmonic content that is additive, and therefore measurable, has a definite final affect on the audio signal. In my opinion, the brilliant design seems to defy gravity and logic, in that there doesn't seem to be a single setting that doesn't improve the sound. But, it always seems to add something that is pleasant sounding and beneficial to the signal, yet it is so definitively “high end” sounding that you can use it for any mastering project in any music category and never feel that there was a better option. I feel this way about a few other EQ's based on their own merits, but the NSEQ-2 definitely serves as the perfect example since it is the ideal in both solid state and vacuum tube Modes!

Cleaner EQ's may follow a minimalist signal path with few capacitors, no transformers, and minimal wiring. The GML and Sontec are the most famous and ideal versions of this type of EQ. They have plenty of settings to choose from, and they can etch out the narrow troublesome tones or smooth out an entire range of Frequencies, but they do so with very little interference to any tonal aspect of the original signal. They are very clean, but they do not lack musicality. They measure very low in distortion and the timing elements are very accurate, yet still there is something sweetening and polishing about their behavior. Even though they are designed for clarity and preciseness, even the manufacturers can describe the character as one device in their line and another as being more precise as another, or bolder in character and robust. Even in the “clean” camp there is a great deal of variety. Program Equalizers are famous for using oversized transformers, hand-crafted inductors, multiple vacuum tubes, and larger-than-life power supplies.

All of the items in their path are known to have a pleasant additive affect in the signal path, and yet they can be used on the most delicate of Program Material with absolute clarity and precision. It seems that even when there is a small measure of harmonic content and intentional heftiness in the signal chain, we can grab the subtle dynamic character of the source and somehow every detail can shine forth. Somehow, despite very low distortion, an incredibly low noise floor, precise timing elements and lack of phase shift, and an impressive flat Frequency response, we can hear the polish and silk and find it always a pleasant addition. Sometimes the benefits of clarity and color are intertwined and serve no reason or measurement for the reason they perform the way that they do.

We can remove nearly all of this character and find the most perfectly clear and clean Mode EQ in digital form, with no aliasing, no distortion, no harmonic character, and a perfect precision. For the most part, this digital EQ might be capable of matching the exact same setting as a Sontec or GML or Pultec, and it will simply not sound good. Should we use it for mastering instead of the analog choice, even if there is some chance that there is some variation of imperfection that we are unable to measure? It is my opinion that we should always rely on our ears for the final verdict, and if this leads our choices to a preference over a measurement, then we can look at character as a choice in “Clean” and “Colorful” Modes regardless of the design.

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How to Mix and Master with EQ – 10 Equalizer Modes – Part Four - CDSoundMaster.com

Audio Recording with Equalizers – 10 Equalizer Modes – Part Four – Linear Phase and Minimal Phase EQ

The usefulness and creative options of an EQ include the ability to separate how one track stands against another and blending multiple sounds together. It defines whether there is a sonic issue that needs correcting, or whether you wish to breath new life into dull source material.

We attach descriptions like “sweetening” and “silky” or “tight” and “punchy” when describing how an EQ affects the signal. When dealing with phase and EQ, considerations move beyond flexibility and layout, and into a scientific realm that some may not wish to concern themselves with. In audio, just like any other discipline, we find that the tools we choose to work with can free us, limit us, or even define our creative decisions. Therefore, we may think of a Mode as simply being determined by the shape of an EQ or the way that it is designed to handle a range of Frequencies or filtering, but Linear Phase and Minimal Phase act as Mode options for the same purposes. Minimal Phase EQ is designed to provide a high quality filtering process that is capable of sounding pure and natural while doing very little to change the timing or cohesiveness of the timing elements of the Program Material.

Phase issues can be the cause of many side effects, but it has become an increasingly small concern with professional gear. In software, phase cohesion takes the role not just of filtering and electronics, but in how sound is handled algorithmically. Therefore, the distinction between Minimal and Linear Phase can involve how an EQ handles actual processing, Gain structure, aliasing and sample rate, edge Frequency filtering, and numerous other issues. Where Minimal Phase can provide natural and precise response, it can also lead to an increase in subtle coloration to the signal the more extreme, and numerous, the filtering options employed.

With Linear Phase EQ, an extremely high fidelity process is used to keep the phase cohesion nearly perfect. The trade off can become more in favor of using less Gain and avoiding audible side effects, and in some cases, trading a bit of artistic musicality for the price of absolute unwavering and pristine timing elements. The choice to favor linearity over proven filtering options with Minimal Phase can lead to ringing and unusual overtones if extreme changes to Gain are attempted, so the choice to use Linear Phase should truly remain hand in hand with making very small, surgical and strategic changes to sound sources. With Minimal Phase, or Minimum Phase as it is sometimes referred to, we have a trade off that finds a balance between the amount of phase a filter allows for, and how well it can provide the shape, slope, and Gain desired. In order to create truly Linear Phase, it has to be possible o adjust all timing elements to the longest potential timing change, which requires a great amount of processing. But, it also places crucial elemental changes to filtering and even can affect the amount of accuracy in actual Frequency and Gain that occur. The most important affect that Phase has on the audio signal is in the sharpness and speed of higher Frequencies, or transients. It is possible for small elements of coloration to occur with any Phase from any EQ that is not purely Linear.

It is my personal opinion that an EQ that claims to be low in timing or Phase shift is generally preferable to Linear Phase, but many Mastering Engineers will disagree. I personally believe that if you listen for the changes that are made, it is much less prevalent to any overt changes in timing to use a Minimal Phase EQ in small amounts than it is to potentially change some of the slope shape and filtering and ripple effects of Linear Phase, at the benefit of near-perfect timing. Whether you are mixing or mastering, the choice of EQ can include specific features like filter type, Gain range, or Frequency settings, and now we can see how the choice of phase cohesiveness can also determine the right choice.

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How to Mix and Master with EQ – 10 Equalizer Modes – Part Three - CDSoundMaster.com

Audio Recording with Equalizers – 10 Equalizer Modes – Part Three – Fixed versus Variable Frequency Modes

When analyzing the difference between Fixed and Variable EQ Frequencies, we once again visit the importance in the design and construction of the analog EQ and its purpose. Fixed Frequencies are common in classic Program Equalizers and in Console EQ's. Although they can be the option of any EQ design, these are the most commonly found in these categories, because they were designed with a specific purpose to focus on specific Frequencies that are the most commonly needed for specific individual vocals and instruments.

The filtering process is specifically chosen in the design of the EQ and can help the user work in a consistent and intentional manner that can define their creative signature, but some find deliberate, predetermined limiting and prefer freely adjustable Frequency selection, as is most commonly found in Mastering EQ's. Variable Frequency Modes can not only provide the ability to get more specific and surgical in our tracking, mixing and mastering processes, but it can also be used dynamically as a song effect. Control and automation of changes in Frequency moves can become a musical element in composition, sound design, and mixdowns that cross the boundary of the art of mixing into the art of actual song creation. This brings EQ into a new category, not just for an engineer's task of tracking, mixing, or mastering, but also at the writing stage.

Using EQ as a filter to change the smooth transition of musical content to swell or pass from one Frequency to the next in smooth transition can act like a sonic ocean wave sweeping by, telling our ears that sound is gliding upwards or downwards, creating an actual musical response instead of making corrective changes.

This determining factor draws a strong line between Fixed and Variable Frequencies, showing how there is more to EQ than just quality and preferred uses. Now, we see that creative choices can cross the barrier between utility into the actual writing of music. Next, lets take a look at Linear Phase and Minimal Phase EQ's.

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How to Mix and Master with EQ – 10 Equalizer Modes – Part Two - CDSoundMaster.com

Audio Recording with Equalizers – 10 Equalizer Modes – Part Two – Boost and Cut EQ

When outlining EQ Modes, we can see that the design of the hardware EQ involves different electronics in the signal path to provide the range of Modes and functionality. I state this because the way in which we interact with EQ in tracking, mixing, mastering, includes Modes that are fixed and selectable, and Modes that are directly affected by the device's construction. In the format of EQ's, we find that different era's and design philosophies provide a different reasoning for the Modes that are provided.

Since I wish for this discussion on Modes to deepen your appreciation, understanding, and decision-making of the 5 EQ types mentioned in the first Post series, I wish to start this series by looking at Boost and Cut Modes in various EQ's. It may seem that Boost and Cut should always mean the same thing and should always be provided as a single option. Since the terms “Boost” and “Cut” may appear obvious and self-explanatory, you may be wondering why I would start with something so seemingly surface. I would reply that the presentation of Boost and Cut is more telling of the use of an EQ than we might assume.

Some designs, including early Program Equalizers, may provide separate controls for Boost and Cut. Many users may not be aware of this, or give it much thought. Since it has become a central part of the mixing process to use digital tools that emulate their analog counterparts, it becomes equally relevant how Boost and Cut are presented, both inside and outside the digital realm. When Boost and Cut are separated out independently, they may also provide different Frequency options for Boost than are provided for Cut, and they may also provide a slightly different Band shape. If both controls are simultaneously usable, this provides a flexibility that we would not tend to consider on our own. You may be able to reshape the Frequencies around a certain range by overlapping the shape of Boost on top of the shape of Cut, thus bending and molding the waveform to lean towards a musical response that brings multiple instrument qualities together, or reduces a wider palette while accentuating and focusing specific narrower instrumentation.

The flexibility in this design is intentional, and though it may seem that separating out Boost and Cut is an antiquated way of handling EQ tasks, it may actually open up more possibilities than our standard Boost and Cut expectations. Normally, we will find Boost and Cut as a single Gain controller in analog and digital form. The Frequency choice, shape, slope, will have its control, along with a separate control for Boost and Gain. Inside the digital domain, we may have tools that go beyond the traditional barriers of analog EQ's, giving us ways to bend, shape, and mold Frequencies and Gain that are far more flexible than what we have seen in the past. Along with these freedoms comes new responsibilities to make the best choices that favor the audio impact over the visualizations provided. Next, I will discuss Fixed versus Variable Frequency EQ Modes.

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How to Mix and Master with EQ – 10 Equalizer Modes – Part One - CDSoundMaster.com

Audio Recording with Equalizers – 10 Equalizer Modes – Part One – Introduction

I have outlined 5 specific types of Equalizers in my previous Posts. There are different ways to categorize EQ's and these are not the only types that one could separate to classify or define, but I believe that I've provided a viewpoint of categorization that helps us to look at EQ's in the manner that we need to utilize them and this viewpoint serves us best. Now, I would like to share with you what I would outline as 10 EQ modes that you will come across. Again, this can help in selecting the tools for the job that you will need the most and to know what to use at a given time. The term “mode” is used in a broad context for this series of articles to make the idea the most beneficial to you.
These 10 EQ Modes are the following:
1. Boost and Cut
2. Fixed versus Variable Frequency
3. Linear Phase versus Minimal Phase EQ
4. Clean or Colorful
5. Fixed “Q” width versus Variable “Q” width
6. High Pass, Low Pass
7. High Cut, Low Cut
8. Band or Bell Shape
9. Shelf
10. Graphic or Parametric

In Part Two of this series, I will discuss Boost and Cut EQ Modes.

How to Mix and Master with EQ – 5 Types of Equalizers – Part Five - CDSoundMaster.com

Audio Recording with Equalizers – 5 Types of Equalizers – Part Five – The Outboard Equalizer

The final type of EQ I want to define is the Outboard Equalizer. In the same way that I have singled out a Console EQ or a Mastering EQ, the Outboard Equalizer can have many overlapping qualities shared with other EQ's. Most modern Equalizers would be considered Outboard EQ's. It has a technical meaning but also an assumed meaning in purpose. The Outboard EQ is simply a hardware device that is not hardwired into the rest of an integrated system. It is designed to offer its sound capability whenever the user wishes to implement it, and it is intended to be left out of the signal chain until it is needed, so the Outboard EQ is designed to sit in an outboard rack awaiting its use.

The Outboard EQ is designed to provide use beyond what is typical of the average in-line EQ or Console EQ, and each Outboard EQ brings its own qualities and characteristics. Some Outboard EQ's are designed to fill a specific gap that is not covered elsewhere. This can be an economic gap, where the user needs something that sounds nicer than their low-to-mid line Console, but is still more cost effective than a $6000 Mastering EQ, and others might consider that Mastering EQ the perfect choice as an Outboard EQ. Other Outboard EQ's might be a graphic Equalizer, designed to control specific set Frequencies without further adjustment options. Other designs could even be Console EQ's from consoles that are different than the one installed in the studio. For instance, a person may have stereo pairs of Outboard EQ's specially racked that give them 1960's German Equalizers that come from a German console, while their studio uses a British in-line Console. They can patch the Outboard EQ to get a different musical flavor from a Console that would be too costly to install the entire hardware.

Other Outboard EQ's include items like Mastering EQ's and Program Equalizers already designed. It is equally notable that some of these EQ's actually started as a prototype for use as a recording or mixing console and gradually became more beneficial as separate EQ devices. So, their very existence helped to define this new EQ category. An Outboard EQ can help a studio diversify its offerings to clients, and it can raise a studio's profile when displaying its “equipment list.” Some Outboard EQ's become popular for their qualities for vocals, and others may act as special filter devices for guitars and bass. The possibilities are endless for the Outboard EQ, and the bottom line tends to be quality, flexibility, and offering something that is either different from the installed Console, or that offers something unusual that the user would not need multiple channels of. The Outboard EQ offers the small studio and independent producer access to excellent devices that they could not afford in larger quantity, and offers flexibility to the larger format studio.

Formats like the API 500 Series provides a perfect scenario for this type of add-on adaptability, where a single power supply range can be used to swap out modules of various devices. This was originally developed to provide the user of an API Console the ability to add a variety of API devices to patch into their API Console. This could act as a sidecar, or it could be a portable version of their favorite API channels. The usefulness of this power supply was slowly recognized by other 3rd party manufacturers, and by formatting their own independent designs to the power supply requirements and card size, they could supply their EQ's to studios using this outboard power source. Since they can be swapped out, this becomes cost effective and provides a great amount of flexibility to the user, and further widens the expanse of external analog hardware choices.