types – Jooyoung's Music Blog

Basics of Synthesizers (1) – Types of Synthesizers

Hello! I’m Jooyoung Kim, a mixing engineer and music producer.

Today, I’ll continue from last time and briefly classify synthesizers. Let’s dive in!

Synthesizers can be categorized based on their synthesis methods. Here’s a breakdown:

No.	Synthesis Method	Description
1	Subtractive Synthesis	Applies filters to a signal to shape the sound.
2	Additive Synthesis	Combines waveforms to create sound.
3	Modulation Synthesis	Modulates one signal using the values of another.
4	Sampling	Modulates pre-recorded sounds (not strictly a synthesizer but often integrated).
5	Physical Modeling	Mathematically models the principles of how real sounds are produced.
6	Phase Distortion	Distorts the speed of phase changes to synthesize sound.
7	Vector Synthesis	Uses a basic wavetable approach, often with a joystick to shape sounds.
8	Spectral Modeling	A type of modeling that uses white noise and variable filters to create sound.
9	Linear Arithmetic	Combines subtractive synthesis with PCM (Pulse Code Modulation) sampling.
10	Formant	A modeling technique based on the frequency spectrum peaks that occur in human speech, called formants.
11	Granular	A sampling method that synthesizes sound by manipulating small units called grains.
12	Wavetable	Synthesizes sound using waveform tables.
13	AI (Neural / Deep Learning)	Trains models to synthesize sounds based on specific parameters.

Quite a list, right?

After the first commercially successful analog synthesizer from Moog appeared, many companies saw the potential for a profitable synthesizer industry. At the same time, academia recognized its research value, leading to numerous collaborations. This fueled rapid advancements in synthesizer development.

As a result, most synthesizer instruments we know today were fully developed before the 2000s.

Today, technologies like Physical Modeling and AI synthesis have advanced synthesizer creation, but we don’t always think of these as “synthesizers.” For example, a modeled piano is perceived as a piano, and a modeled woodwind as a woodwind.

*Pianoteq is a synthesizer, but it doesn’t feel like one, does it?*

Where’s the Future of Virtual Instruments and Performers Headed? Meet Melisma AI Strings & Woodwinds

I previously introduced a tool that uses AI and sheet music to synthesize strings that sound incredibly realistic. I believe this is the direction future synthesizers will take.

*The recently released Serum 2 synthesizer. I think this is about as far as what we consider “synthesizer” instruments will evolve.*

Once you master a few synthesizers, you’ll find that the parameters are largely similar across others. In upcoming posts, I’ll explore representative synthesizers for each synthesis method and how to use them. Reading through these will help you navigate complex synthesizer workflows.

Until next time!

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.

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.

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.

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.

Cut Filter, Band Pass Filter
Shelving EQ
Notch Filter
Graphic EQ

That’s it for today.

Parametric EQ
Dynamic EQ
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!

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