Tag: basic

Basics of Mixing – 6.7 Limiters and Clipping

Hello, I’m Jooyoung Kim, an engineer and music producer.

We’ve discussed various processors that control dynamics. Today, let’s talk about limiters and clipping.

Let’s dive right in!

Limiters

A limiter is a type of compressor. Generally, when the ratio exceeds 10:1, we call it a limiter. When it reaches ∞:1, it’s often referred to as a brickwall limiter.

Limiters are processors that aggressively compress sound to prevent it from exceeding a certain volume level. A simple example of this would be guitar effects like distortion or overdrive, which are types of limiters. In mastering, limiters are used at the final stage to ensure the volume doesn’t exceed a certain level.

Any limiter, when viewed on a waveform, shows the top and bottom parts being cut off. This truncation introduces strong harmonic distortion, known as clipping, which we can perceive as a distorted sound.

Distortion-type limiters result in noticeable clipping, producing a heavily distorted sound. To minimize such distortion, some compressors/limiters include a feature called soft clipping.

Clipping / Soft Clipping

Elysia Alpha Compressor with Soft Clipping Function

Soft clipping gently smooths out the sharp edges of clipping. When a sine wave undergoes limiting with soft clipping, the result is a waveform that doesn’t have the abrupt cuts seen in regular clipping.

While soft clipping still introduces distortion, the sound is smoother compared to hard clipping. Using limiters or soft clipping helps to increase the overall loudness of a track. The reason for boosting volume is that people tend to perceive louder music as higher quality. However, equal LUFS (Loudness Units relative to Full Scale) values do not always mean the perceived volume is the same. For example, in vocal music, if the vocals are prominent, the music may seem louder even with similar LUFS values.

Even if you’re not mastering your own tracks, considering these aspects during mixing can help you create better productions.

Next time, I’ll explore reverb effects like delay. See you then!

Basics of Mixing – 6.6 De-Essers and Multiband Compressors

Hello, I’m Jooyoung Kim, an engineer and music producer.

Today, we’ll delve into two subtypes of compressors: De-Essers and Multiband Compressors.

Let’s get started!

De-Essers

A De-Esser is a type of compressor that reduces “ess” sounds, also known as sibilance. Waves even has a De-Esser named “Sibilance” specifically for this purpose.

Sibilance typically falls between 3kHz and 10kHz. A De-Esser works by activating the compressor when the sound in this specific range exceeds a certain threshold. Unlike using an EQ, which reduces the selected frequency range across the entire source, a De-Esser targets only the problem area. You can think of it as a single-band compressor.

De-Essers are not only useful for reducing vocal sibilance but also for taming harsh high frequencies in acoustic guitar strums and other similar sounds.

For instance, the Oxford SuprEsser by Sonnox offers a wide range of frequencies to adjust, making it versatile for various applications beyond its primary function of reducing high frequencies.

Multiband Compressors

A Multiband Compressor allows you to set different compression parameters for different frequency ranges. This is particularly useful when dealing with audio sources containing multiple instruments, which can be challenging to manage with a simple compressor.

For example, you might use a Multiband Compressor on a drum bus or to handle looped sources from platforms like Splice. It’s also commonly used in mastering.

Sidechain functionality in these compressors can add an interesting and effective dynamic to your tracks. For example, you can sidechain the low frequencies of other instruments to duck when the kick drum hits, or use it to carve out space for the vocal’s frequency range.

I’ll cover sidechain techniques more thoroughly in a future post, but mastering sidechain within dynamic plugins can significantly enhance the fun and effectiveness of your mixing. I’m not an expert yet, but I’m learning alongside you.

That’s all for today. See you in the next post!

Basics of Mixing – 6.3 Types of Compressors

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

Today, we will discuss the different types of compressors based on their operating principles.

Before we begin, it’s important to note that most compressors we talk about today are named after the specific components used as attenuators in each type. These components give each type its unique characteristics, so understanding these classifications is essential.

Shall we get started?

1) Variable-Mu (Vari-Mu)

Vari-Mu compressors use vacuum tubes as attenuators. (Note that just because a compressor has vacuum tubes doesn’t automatically make it a Vari-Mu compressor.)

“Variable” means adjustable, and “Mu” (μ) stands for gain. So, Variable-Mu essentially means variable gain.

This might sound confusing, but essentially, as the input signal increases, the current to the vacuum tube’s grid decreases, thus varying the output level and creating adjustable gain.

Vari-Mu compressors have a non-fixed ratio and typically feature a soft knee. They also impart significant coloration to the sound due to the nature of vacuum tubes.

Famous examples include the Fairchild 670, Manley Variable Mu, and Chandler Limited RS124. These were predominantly used in the early days of compressors.

2) Optical (Opto)

Opto compressors use an optical isolator (photo transistor) as the attenuator. The intensity of the light changes according to the input signal, which in turn adjusts the compression. The release time varies significantly depending on the amount of compression.

A well-known Opto compressor is the LA-2A, which was also called a 2-step compressor due to the significant difference in reduction levels around -3dB. This characteristic makes it popular for vocal sources.

Both vacuum tubes and transistors can be used for gain control in Opto compressors. For instance, the LA-2A uses vacuum tubes, while the LA-3A replaced these with transistors.

The Tube-Tech CL1B is another common Opto compressor found in studios.

3) Solid State

Solid State compressors use transistors or diodes as the attenuators. When transistors first became available, they replaced vacuum tubes due to their lower power consumption and smaller size.

The UA 1176 is a prime example and remains one of the most famous Solid State compressors. It is known for its very fast attack and release times. The Blue Stripe version of the 1176 is especially noted for its strong coloration, making it a favorite for drum sources.

4) Diode Bridge

Diode Bridge compressors use a diode bridge circuit for signal attenuation. These became popular in the 1960s for their faster response compared to typical Opto compressors and lower distortion compared to many FET designs.

Notable examples include the Neve 33609, 2254, Chandler Limited Germanium, and EMI TG12345.

5) VCA (Voltage Controlled Amplifier)

VCA compressors use a Voltage Controlled Amplifier as the attenuator. A VCA adjusts the amplification based on the input signal’s voltage, allowing precise control over the input signal level. VCA designs typically have low distortion and less coloration compared to Vari-Mu, Opto, and Solid State compressors.

The dbx 160 is a representative VCA compressor, along with the Amek 9098 Compressor Limiter, SSL G Compressor, API 2500, Vertigo VSC-3, and Shadow Hills Mastering Compressor (excluding the Opto section).

6) PWM (Pulse Width Modulation)

PWM compressors use pulse width modulation to control signal strength. They can turn on and off in less than 1 nanosecond, making them extremely responsive with even less distortion than VCA compressors.

Famous PWM compressors include the Crane Song STC-8 and the Pye 4060 and 5060.

7) Digital

Digital compressors are not replicas of analog compressors but are designed to detect the signal level in real-time and apply compression based on the set threshold and ratio.

Digital compressors may introduce harmonic distortion due to nonlinear responses and aliasing, although many modern plugins mitigate aliasing with oversampling.

Despite potential distortion, digital compressors typically have less coloration and are cleaner than analog counterparts. Most basic DAW compressor plugins fall into this category.

Conclusion

Nowadays, most compressors used are plugins. Even if they replicate the same vintage hardware, their characteristics can differ, making memorizing all these details unnecessary.

When purchasing or using a compressor for the first time, it’s helpful to understand its operating principle to get a rough idea of its characteristics.

Also, remember that digital replicas may still suffer from aliasing issues. The only way to completely avoid this is by using the actual hardware.

That’s it for today. See you in the next post!

Basics of Mixing – 6.2 Compressor Operation Principles

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

Today, we’ll discuss the basic principles of how a compressor works.

A compressor is a device that reduces sounds exceeding a set volume threshold by a certain ratio.

You can set how quickly the compressor reacts when the sound exceeds the threshold (Attack) and how quickly it stops compressing when the sound drops below the threshold (Release).

The four basic parameters of a compressor are Threshold, Ratio, Attack, and Release. By making louder sounds quieter and leaving quieter sounds as they are, a compressor helps to level out the volume.

Compressed sounds tend to become quieter. Therefore, to match the volume back to the original level, you use the Output Gain parameter.

Many compressor plugins have an Auto Gain feature that automatically adjusts the volume, but in my experience, none of them have worked well enough. So, if your compressor has an Auto Gain feature, it’s best to turn it off.

Another setting to consider is the Knee. Hard Knee means the compressor kicks in immediately once the threshold is exceeded, while Soft Knee allows for a more gradual compression as the sound approaches the threshold.

This covers the most basic operation and usage of a compressor.

However, just explaining the parameters and telling you to try them out isn’t enough guidance, right?^^;;

For example, the classic compressor LA-2A has a fixed ratio of 4:1.

Similarly, most versions of the 1176 compressor (excluding the AE version) start with a minimum ratio of 4:1. Starting around these settings can be a good approach.

The appropriate threshold setting varies greatly depending on the desired effect. If you’re new to this and have no idea where to start, try aiming for a Gain Reduction of around -3dB.

Other considerations include:

  1. Setting a fast Attack can change the transient feel of the sound, affecting the instrument’s groove.
  2. Setting a fast Release can cause the sound to pump as it recovers quickly.

Each instrument and sound source is different, so there’s no one-size-fits-all guide. Additionally, many compressors include saturation, which adds coloration to the sound, so various factors need to be considered.

Still, it’s important to start experimenting! By testing out different compressors, you’ll begin to understand which settings work best in different situations.

In the next post, we’ll look at the different types of compressors. Understanding their characteristics will give you a better grasp of how to use them effectively.

See you in the next post!