If you're into music production and mixing, you probably know how essential compressors are. They help control the dynamic range of audio signals, giving them a more balanced and polished sound. However, using a compressor correctly is not always easy, and you may not know which settings to use to get the sound you want.
This article will explain how to use a compressor to achieve different sounds and discuss the different compressor settings like ratio, threshold, and others that you can use. We'll also discuss the different types of sounds you can create with a compressor.
Two Types of Sounds You Can Achieve with a Compressor
Before discussing compressor settings, let's talk about the two main types of sounds you can create with a compressor.
Transparent sound: This type of sound is ideal for pop, rock, and electronic music where you want to create a polished and controlled sound without adding any significant coloration to the original sound.
Colored sound: This type of sound is often used in hip-hop, R&B, and funk genres. You want to create a more aggressive and dynamic sound, so you'll need to add some coloration to the original sound.
Compressor Settings You Need to Know
To use compressors effectively, you need to know the following compressor settings:
Threshold: The threshold is the level at which the compressor begins to reduce the gain of the audio signal. You should set the threshold so that the compressor engages only when the audio signal becomes too loud. If you set the threshold too high, the compressor won't engage, and you won't hear any effect. If you set it too low, the compressor will engage too often, and the sound will become squashed.
Ratio: The ratio determines how much the compressor reduces the gain of the audio signal once the threshold is reached. A low ratio (e.g., 2:1) means the compressor will reduce the gain only slightly, while a high ratio (e.g., 10:1) means the compressor will reduce the gain significantly. For a transparent sound, use a ratio of around 2:1 to 4:1. For a more colored sound, use a higher ratio, like 6:1 to 10:1.
Attack and Release: The attack time determines how quickly the compressor reacts to changes in the audio signal, while the release time determines how quickly the compressor stops reducing the gain once the audio signal drops below the threshold. For a transparent sound, use a fast attack time (e.g., 1ms to 10ms) and a medium release time (e.g., 50ms to 100ms). For a more colored sound, experiment with slower attack times (e.g., 10ms to 50ms) and longer release times (e.g., 200ms to 500ms).
Knee: The knee setting determines how the compressor engages once the threshold is reached. A hard knee means the compressor engages abruptly once the threshold is reached, while a soft knee means the compressor engages more gradually as the audio signal approaches the threshold. For a transparent sound, use a soft knee to ensure a smoother reduction in gain. For a more colored sound, experiment with a hard knee to create more aggressive compression.
Makeup Gain: The makeup gain compensates for the reduction in gain caused by the compressor. It boosts the overall level of the audio signal to make up for the gain reduction. Set the makeup gain so that the overall level of the audio signal remains consistent.
Types of Compressors
There are different types of compressors available, including optical, FET, VCA, and Vari-Mu. Each type of compressor has its own unique sound, so it's important to understand their characteristics to choose the best one for your needs.
Optical Compressor: An optical compressor works by using a light source and a photocell. When the input signal exceeds a certain threshold, the light source activates the photocell, which reduces the gain of the signal. Optical compressors are known for their smooth, transparent sound and are often used on vocals and acoustic instruments.
FET Compressor: A FET (Field-Effect Transistor) compressor uses a FET transistor to control the gain reduction. FET compressors are known for their fast attack time, which makes them suitable for processing drums and other percussive instruments. They also add a subtle harmonic distortion that can add warmth and character to the sound.
VCA Compressor: A VCA (Voltage-Controlled Amplifier) compressor uses a voltage-controlled amplifier to control the gain reduction. VCA compressors are known for their precise and transparent sound, which makes them suitable for a wide range of applications. They are often used in mixing and mastering.
Vari-Mu Compressor: A Vari-Mu compressor uses vacuum tubes to control the gain reduction. Vari-Mu compressors are known for their warm, musical sound and gentle compression. They are often used on vocals, bass, and other instruments that need to be tamed without losing their character.
Choosing the Right Compressor:
When choosing a compressor, consider the specific application and desired sound. Different compressors excel in different areas, so it is important to choose the right one for the job. Consider the type of compressor, as well as its specific features and capabilities.
A compressor is an essential tool for any music producer or engineer. By controlling the dynamic range of a signal, compressors can help balance the mix, add sustain to a guitar, tighten up a drum kit, and much more. Understanding how to use compressors in music production and mixing can greatly enhance the quality and balance of audio signals. Remember to choose the right compressor for the job, and always experiment and listen critically to achieve the best results.
Practical Examples and Case Studies:
To achieve a transparent sound, use a low ratio (around 2:1 to 4:1) and a fast attack time (1ms to 10ms) with a medium release time (50ms to 100ms). For a colored sound, experiment with higher ratios (6:1 to 10:1) and slower attack times (10ms to 50ms) with longer release times (200ms to 500ms). A soft knee is recommended for a transparent sound, while a hard knee can create a more aggressive compression for a colored sound.
When processing drums, a FET compressor with a high ratio and fast attack time can create a punchy, aggressive sound. For vocals, an optical compressor with a low ratio and slower attack and release times can create a smooth, natural sound. In mastering, a VCA compressor with a low ratio and transparent sound is often used to maintain the integrity of the mix.
Guitars: Compression can be used to tame the dynamic range of a guitar signal, allowing for a more consistent and controlled sound. This can be particularly useful for rhythm guitar parts. Start by setting a low threshold and a low ratio, and adjust the attack and release times to suit the performance. A gentle compression can also add sustain and thickness to lead guitar parts.
Vocals: Compression is a staple in vocal processing, as it can even out the volume of a performance and help it sit better in a mix. Start by setting a moderate ratio and a low threshold, and adjust the attack and release times to allow the natural dynamics of the performance to come through. A high-pass filter can also be used to remove any low-frequency rumble.
Bass: Compression can be used to add punch and sustain to a bass guitar, as well as to help it sit better in a mix. Start by setting a moderate ratio and a low threshold, and adjust the attack and release times to allow the natural dynamics of the performance to come through. A low-pass filter can also be used to remove any high-frequency noise or harshness.
Drums: Compression is often used on drums to add impact and control the dynamic range. For kick drum, start by setting a moderate ratio and a low threshold, and adjust the attack and release times to suit the performance. For snare drum, a higher ratio and faster attack time can be used to add snap and definition. Compression can also be used on other drum elements like toms and overheads to help them sit better in a mix.
Mixing: Compression is an essential tool in mixing, allowing for better control of the overall dynamic range of a mix and helping to glue everything together. Start by using compression on individual tracks as needed, then consider using a bus compressor on the entire mix to add cohesiveness and punch. Be careful not to over-compress, as this can lead to a lifeless and flat-sounding mix.
These are just a few examples of how compression can be used in music production. Experimentation and careful listening are key to finding the right settings for each situation.
Have fun! :)
References: Sound on Sound, Mix Magazine, Tape Op Magazine