Tag: EQ

Basics of Mixing – 5.2 Types of EQ (2)

Hello, this is Jooyoung Kim, an engineer and music producer.

Basics of Mixing – 5.2 Types of EQ (1)

Today, I will continue discussing the types of EQ from the previous post, focusing on Parametric EQ, Dynamic EQ, and Baxandall EQ.

5) Parametric EQ

Parametric EQ was designed by the renowned engineer George Massenburg. It is commonly found as a built-in EQ in DAWs.

This type of EQ allows you to select the frequency you want to adjust and set the Q Factor, which determines the bandwidth of the adjustment.

These are examples of Parametric EQs!

Parametric EQ is used not only for musical purposes but also for addressing issues with sound sources. It can handle problems such as proximity effect from microphones, Singer’s Formant (a specific resonance found in vocalists), room resonance, and high-pitched squeaking noises from strings.

6) Dynamic EQ

Dynamic EQ combines the functions of a compressor with an EQ. It works similarly to a multiband compressor but with slight differences in how bands are set and how it operates.

  1. A multiband compressor uses cut filters to define bands, while a Dynamic EQ defines bands according to the EQ settings.

As mentioned in the previous post, cut filters cause a phase shift of π/2 for every 6dB/oct. This means that multiband compressors can alter the sound due to phase changes even without any settings.

  1. Depending on the Dynamic EQ, most do not allow you to set the ratio, attack, and decay like a compressor does. Typically, you can only set the threshold and the amount of volume reduction or increase.

Because of this, the compression curve of a Dynamic EQ can appear different. The pink curve is from Fabfilter’s Pro-Q3, and the red curve is from Initial Audio’s Dynamic EQ. Although both are Dynamic EQs, their behavior is quite different.

Interpreting Fabfilter’s unique curve, it seems to compress the sound up to a certain point, after which it stops compressing and simply reduces the volume of the sound.

In simpler terms, for Pro-Q3, if the sound exceeds a certain level, it follows the dynamic curve (green) rather than the set yellow curve, acting more like a simple EQ.

However, their usage is generally similar. Dynamic EQs are often used when you want to reduce specific frequency bands. You can choose based on your preference.

7) Baxandall EQ

Baxandall EQ was introduced by Mr. Baxandall in 1952 through Wireless World magazine without royalties, making it widely used.

Due to its minimal phase issues, it is frequently used in mastering. It’s effective for adjusting broad frequency ranges, such as lifting high or low frequencies.

Examples include Tilt EQ and Dangerous’s Bax EQ.

This concludes the overview of various types of EQ. Besides these functional classifications, there are also categories like Zero Latency/Linear Phase/Normal EQs, and whether they are used for musical (Tone Shaping) or technical (Surgical) purposes.

I will continue with these topics in the next post.

See you next time!

Basics of Mixing – 5.2 Types of EQ (1)

Hello, this is Jooyoung Kim, an engineer and music producer.

There are numerous types of EQs available.

Today, I will describe some of these EQs.

  1. Cut Filter, Band Pass Filter
  2. Shelving EQ
  3. Notch Filter
  4. Graphic EQ

That’s it for today.

  1. Parametric EQ
  2. Dynamic EQ
  3. Baxandall EQ

1) Cut Filter, Band Pass Filter

Cut filters are quite common and widely used. Low Cut and High Cut filters are frequently applied.

Low Cut filters are used to reduce low-frequency noises like vibrations from the floor or other low-frequency disturbances.

High Cut filters reduce high frequencies to create a lo-fi sound or to achieve a specific sound characteristic.

Low Cut filters are also known as High Pass filters because they let higher frequencies pass through. Similarly, High Cut filters are known as Low Pass filters.

The amount of reduction is often labeled as -6dB per octave (-6dB/oct) or Pole (with 1 Pole equating to -6dB/oct). Typical values include -6dB/oct, -12dB/oct, -18dB/oct, -24dB/oct, and so on.

While not exactly the same, a Band Pass filter can be thought of as a combination of these two filters.

These filters significantly alter the phase.

The phase shift graph above shows the phase change when a -12dB/oct Low Cut filter is applied. You can see a phase shift of π (3.14) in the low-frequency range.

Comparing this with other phase graphs, you will realize that this is quite a significant phase shift. A large phase shift means that the sound will be quite different from the original. Therefore, using Cut filters indiscriminately can result in a sound that is far from the intended one.

Basics of Mixing – 2.2 Phase and Interference

I have previously discussed issues caused by phase cancellation.

Each Pole causes a phase shift of π/2. Using a steep Low Cut filter like -24dB/oct can result in a phase shift of up to 2π, so it’s generally not recommended to use it excessively.

However, use it when necessary.

2) Shelving EQ

Shelving EQ, also known as Shelving Filter, adjusts the volume of frequencies in a shelf-like shape, as the name suggests.

It is used to lift or lower an entire frequency band.

As shown in the image above, Shelving EQs cause less phase shift, making them a good alternative to Cut filters.

3) Notch Filter

Notch filters can be used to eliminate resonances that are difficult to control with other EQs or to create specific musical effects.

It is quite rare to use Notch filters in mixing. They are typically used for problematic sources that are hard to manage otherwise. I personally use them perhaps once a year in mixing.

In music production, Notch filters can be used on synthesizers to create interesting effects by modulating frequencies over time with an LFO.

4) Graphic EQ

With a Constant Q setting, the Q value remains the same as the volume changes. With a Variable (Non-Constant) Q setting, the Q value changes with the volume adjustments.

These internal settings are usually described in the manual, so it’s best to read it for proper usage.

The phase shift is minimal. The common Bell-type Parametric EQ, which I will explain next time, also changes phase in a similar way.

In studio mixing, Graphic EQs are rarely used due to convenience. However, knowing these theories might be useful, especially if you also do live mixing.

Describing Parametric EQ, Dynamic EQ, and Baxandall EQ would make this post too long, so I will continue in the next article.

The main point I wanted to convey today is the importance of considering phase changes when using EQs.

If the sound is different from what you intended after adjusting the frequencies, it is often due to phase changes.

If it sounds good to your ears, that’s what matters. However, understanding what to watch out for and why can lead to more efficient and faster decision-making.

See you in the next post!

Basics of Mixing – 5.1 What is EQ (Equalizer)?

Hello, this is Jooyoung Kim, engineer and music producer.

Today, I want to talk about the basics of EQ. There’s so much to cover, I’m not sure where to begin… But let’s dive in!

EQ is a tool that allows you to adjust the volume based on frequency. Why would we need something like this?

The main reasons are:

1) To alter the tone of an instrument
2) To change the position of an instrument in the stereo image
3) To prevent sounds from different instruments from overlapping
4) To fix issues with recorded sources

    We’ll go into more detail on the types of EQ in a later post, but for now, let’s discuss these reasons in more depth.

    • To Alter the Tone of an Instrument

    A drum kick typically handles low frequencies. But is it only low frequencies? Of course not.

    High frequencies contribute to the attack, giving it a punchy feel, while the midrange can be quite prominent and can mask other instruments.

    Thus, by using EQ, you can adjust these frequencies to create a balance that fits the song. This applies not just to kicks but to other instruments as well.

    • To Change the Position of an Instrument in the Stereo Image

    Using EQ to adjust an instrument can change its position in the stereo image. In typical speakers with a tweeter on top and a woofer on the bottom, cutting high frequencies can make a sound seem to move lower, while cutting low frequencies can make it seem to move higher.

    You can also adjust just the left or right side with EQ to move the sound diagonally.

    • To Prevent Sounds from Different Instruments from Overlapping

    Instruments like acoustic piano, acoustic guitar, and synth pads produce sounds across a wide range of frequencies, which can cause other instruments, like vocals, to be masked.

    This phenomenon, where instruments obscure each other, is known as masking. Kick and bass are classic examples of instruments that can mask each other. EQ is a traditional and fundamental way to address this issue.

    • To Fix Issues with Recorded Sources
    Millhouse, Thomas & Clermont, Frantz. (2006). Perceptual characterization of the singer’s formant region: A preliminary study. 253-258.
    Singer’s Formant

    When recording instruments, resonance in the room can cause certain frequencies to be overly emphasized.

    There is also something called the Singer’s Formant, a specific resonance found in trained opera singers. Instruments, too, can have unique resonances or harsh sounds. For example, when recording a violin, the bow can produce a squeaky sound at certain high frequencies.

    EQ is used to resolve these resonances.

    Today, we covered why EQ is used. In the next post, we’ll discuss the different types of EQ and their uses. See you next time!