Types of Compression: On Music Production

In music production, various types of compression are used to control the dynamic range of audio signals, shape the sound, and enhance the overall mix. Here are some common types of compression used in music production:

Peak Compression:

Purpose: Controls transient peaks in the audio signal.

Application: Prevents clipping and distortion caused by sudden spikes in volume.

Peak compression is a fundamental technique in music production used to control transient peaks in audio signals. These peaks, if left unchecked, can lead to clipping and distortion. Peak compression helps to maintain a more consistent and controlled level of the audio signal, ensuring that it stays within acceptable limits.

1. Understanding Transient Peaks:

• Transients are short bursts of sound that occur at the beginning of a sound event, typically associated with the attack phase of a musical instrument or a percussive sound. Transient peaks represent the highest point of these bursts and can be significantly louder than the average level of the audio signal.

2. Purpose of Peak Compression:

• The primary purpose of peak compression is to tame these transient peaks, preventing them from causing clipping and distortion in the audio signal. By reducing the level of the transients, peak compression ensures that the signal remains within the dynamic range of the recording medium or playback system.

3. Applications of Peak Compression:

• Preventing Clipping: In digital audio, exceeding the maximum level can result in clipping, which introduces unwanted distortion. Peak compression helps to prevent clipping by reducing the amplitude of transient peaks.
• Instrumental and Vocal Balance: Peak compression is often applied to individual tracks, such as drums or vocals, to ensure a consistent and controlled level. This is crucial for maintaining a balanced mix where no single element dominates.
• Mastering: In the mastering stage, peak compression is applied to the overall mix to ensure that the entire track stays within the desired loudness range without sacrificing the integrity of the original recording.

4. Using Peak Compression Effectively:

• Selecting the Right Compressor: Choose a compressor with fast attack and release times to effectively capture and control transient peaks. A transparent compressor is often preferred for peak compression to avoid coloration of the sound.
• Setting the Threshold: Set the threshold so that the compressor engages only when transient peaks exceed a certain level. This ensures that the compressor acts specifically on the peaks without affecting the entire signal.
• Adjusting Attack and Release: Experiment with the attack and release settings to find a balance that effectively controls transients without introducing pumping or unnatural artifacts. A faster attack time is generally preferred for peak compression.
• Ratio and Makeup Gain: Set a moderate compression ratio (e.g., 4:1) for peak compression. Adjust the makeup gain to bring the compressed signal back to the desired level, maintaining a natural and balanced sound.

5. Common Mistakes to Avoid:

• Overcompression: Applying excessive peak compression can result in a lifeless and overly controlled sound. Use compression judiciously, ensuring that the natural dynamics of the music are preserved.
• Ignoring Context: Consider the musical context when applying peak compression. Different genres and styles may require varying levels of dynamic control.

RMS Compression (Leveling):

Purpose: Evens out the overall volume of a signal by compressing average levels.

Application: Balances the overall loudness of a track or instrument.

RMS compression, often referred to as leveling, is a critical technique in music production used to control the average volume levels of audio signals. Unlike peak compression, which focuses on transient peaks, RMS compression targets the overall amplitude of a signal, providing a smoother and more consistent sound.

1. Understanding RMS (Root Mean Square):

• RMS is a mathematical measure of the average power of an audio signal. Unlike peak level, which reflects the highest instantaneous amplitude, RMS provides a more balanced representation of the signal’s overall intensity over time. RMS compression responds to the average loudness rather than the transient peaks.

2. Purpose of RMS Compression:

The primary purpose of RMS compression is to even out the overall volume of a signal, creating a more consistent and controlled dynamic range. This helps to balance the mix and ensures that no individual element dominates or gets lost in the overall sound

3. Applications of RMS Compression:

• Balancing Individual Tracks: RMS compression is often applied to individual tracks, such as vocals, guitars, or synths, to maintain a more uniform and balanced level throughout the performance.
• Creating a Leveled Mix: When applied to multiple tracks in a mix, RMS compression helps achieve a balanced and cohesive sound by reducing the dynamic range and preventing certain elements from being too prominent or too quiet.
• Mastering: In the mastering stage, RMS compression is used to provide the final touch to the overall mix, ensuring that the entire track maintains a consistent loudness level.

4. Using RMS Compression Effectively:

• Choosing the Right Compressor: Select a compressor with a moderate attack time and a relatively fast release time. The goal is to respond to the average level of the signal without overly affecting the transients.
• Setting the Threshold: Adjust the threshold so that the compressor engages when the signal exceeds a certain average level. This ensures that the compressor reacts to the overall loudness rather than transient peaks.
• Adjusting Ratio and Makeup Gain: Use a moderate compression ratio (e.g., 2:1 to 4:1) for RMS compression. Adjust the makeup gain to bring the compressed signal back to the desired level, creating a more balanced and leveled sound.
• Experimenting with Attack and Release: Fine-tune the attack and release settings to find a balance that responds smoothly to the changing dynamics of the audio signal. Avoid excessively fast attack times to prevent unwanted artifacts.

5. Common Mistakes to Avoid:

• Over-compression: Applying too much RMS compression can lead to a lifeless and dull sound. Use moderation to maintain a natural dynamic feel while achieving the desired level consistency.
• Ignoring Musical Context: Consider the genre and style of the music when applying RMS compression. Different musical contexts may require varying levels of dynamic control.

Multiband Compression:

Purpose: Applies compression to specific frequency bands independently.

Application: Allows for targeted control of different frequency ranges, particularly useful for complex mixes.

Multiband compression is a powerful tool in music production that allows for targeted control of different frequency bands within an audio signal. Unlike traditional compression, which processes the entire frequency spectrum as a whole, multiband compression divides the audio signal into multiple frequency ranges, enabling precise adjustments to specific areas of the sound.

1. Understanding Multiband Compression:

• Multiband compression operates by splitting the audio spectrum into distinct frequency bands, typically three or more. Each band is then processed independently through its own compressor. This allows for the selective compression of specific frequency ranges without affecting others.

2. Purpose of Multiband Compression:

The primary purpose of multiband compression is to address frequency-specific dynamics and tonal balance issues within a mix. It provides a more surgical approach to compression, allowing you to target problematic areas without affecting the entire frequency spectrum. Multiband compression is particularly useful for complex mixes where different elements may compete for attention in specific frequency ranges.

3. Applications of Multiband Compression:

• Taming Harshness or Muddiness: Multiband compression can be applied to control harsh frequencies in vocals or instruments or reduce muddiness in the low end by compressing specific frequency bands.
• Enhancing Presence: By selectively compressing midrange frequencies, you can enhance the presence and clarity of vocals or lead instruments without affecting the overall mix balance.
• Managing Bass Dynamics: Multiband compression is effective in controlling the dynamics of the low-frequency range, ensuring a tight and well-defined bass response without sacrificing the impact.
• Mastering: In mastering, multiband compression is often used to address imbalances in the frequency spectrum and achieve a more polished and cohesive sound.

4. Using Multiband Compression Effectively:

• Selecting the Right Parameters: Choose a multiband compressor with adjustable crossover points for each frequency band. This allows you to define the boundaries between bands and tailor the compression to specific ranges.
• Setting Thresholds and Ratios: Adjust the threshold and ratio settings independently for each band based on the dynamics of the frequency range you are targeting. Consider using moderate ratios and thresholds to avoid over-compression.
• Adjusting Attack and Release Times: Experiment with attack and release times for each band to tailor the compression envelope to the characteristics of the frequencies being processed. Faster attack times may be suitable for controlling transients, while slower release times can smooth out sustained elements.
• Monitoring and A/B Testing: Constantly monitor the effect of multiband compression on the overall mix. Use A/B testing to compare the processed and unprocessed versions to ensure that the compression enhances rather than detracts from the musicality of the mix.

5. Common Mistakes to Avoid:

• Overusing Multiband Compression: Applying multiband compression too aggressively or across too many frequency bands can result in an unnatural and sterile sound. Use it judiciously to address specific issues.
• Neglecting Phase Considerations: Be mindful of phase interactions between the compressed bands. Some multiband compressors offer phase-linear options to minimize phase issues.

Parallel Compression (New York Compression):

Purpose: Blends compressed and uncompressed signals for a dynamic mix.

Application: Adds sustain and body to a signal without sacrificing transient impact.

Parallel compression, often referred to as New York compression, is a popular technique in music production that involves blending a heavily compressed signal with the original uncompressed signal. This approach allows for the retention of the natural dynamics of the source while adding sustain, thickness, and intensity to the overall sound.

1. Understanding Parallel Compression:

Parallel compression involves creating a parallel (duplicate) track alongside the original audio track and applying heavy compression to the duplicate while leaving the original uncompressed. The compressed and uncompressed signals are then mixed together to achieve a balance between the natural dynamics and the enhanced, compressed sound.

2. Purpose of Parallel Compression:

The primary purpose of parallel compression is to add sustain, body, and impact to a sound without sacrificing the natural dynamics of the original performance. It is especially useful for enhancing the presence of drums, vocals, and other dynamic elements in a mix.

3. Applications of Parallel Compression:

• Drums: Parallel compression is widely used on drum tracks to bring out the details of the softer hits (such as ghost notes) while adding weight and punch to the overall sound.
• Vocals: It can be applied to vocals to add thickness and sustain without losing the natural dynamics of the singer’s performance.
• Guitars: Parallel compression is effective in adding sustain and thickness to guitar tracks, particularly in genres like rock and metal.
• Mix Bus: Some engineers apply parallel compression to the entire mix bus during the mastering stage to add overall glue and cohesion to the mix.

4. Using Parallel Compression Effectively:

• Duplicate the Track: Create a duplicate of the track you want to process in parallel. This can be achieved by copying the track or using a send/return configuration.
• Apply Heavy Compression: On the duplicated track, apply heavy compression settings with a low threshold, high ratio, and fast attack/release times. This is where the characteristic “New York Compression” sound is created.
• Blend the Signals: Adjust the volume fader or wet/dry mix control to blend the compressed and uncompressed signals to achieve the desired balance. Start with the parallel track at a low volume and gradually increase to find the sweet spot.
• Fine-Tune Compression Parameters: Experiment with different compression settings on the parallel track to achieve the desired level of sustain and impact. The goal is to enhance the desired characteristics without overdoing it.

5. Common Mistakes to Avoid:

• Overcompression: Applying excessive compression on the parallel track can result in an unnatural and overly compressed sound. Be mindful of the balance between the compressed and uncompressed signals.
• Ignoring Phase Issues: Check for phase coherence between the compressed and uncompressed signals. Phase issues can arise, affecting the clarity and focus of the sound.

Sidechain Compression:

Purpose: Uses the input from one signal to control the compression of another.

Application: Commonly used in dance music to duck the volume of a bassline when the kick drum hits.

Sidechain compression is a powerful technique in music production that involves using the signal from one source to control the compression applied to another. This process allows for dynamic shaping of the mix, particularly in situations where conflicting elements need to coexist harmoniously.

1. Understanding Sidechain Compression:

• Sidechain compression operates by using the amplitude (volume) information from one track, known as the sidechain input, to control the compression applied to another track, known as the main or target track. This technique is commonly used to create space in the mix, emphasize certain elements, or manage conflicting frequencies.

2. Purpose of Sidechain Compression:

The primary purpose of sidechain compression is to dynamically control the volume of one track based on the amplitude of another. This can help resolve conflicts between different elements in a mix, allowing specific elements to stand out while others are momentarily attenuated.

3. Applications of Sidechain Compression:

• Ducking for Vocal Clarity: Sidechain compression is often used to duck the volume of music elements (e.g., pads, chords) when vocals are present. This creates space for the vocals to be more prominent without changing their level manually.
• Bass and Kick Interaction: In dance music, sidechain compression is frequently applied to the bass using the kick drum as the sidechain input. This technique creates a “pumping” effect, emphasizing the kick while allowing the bass to smoothly blend in.
• Instrument Separation: Sidechain compression can be used to separate similar instruments or sounds in the mix. For instance, using a guitar as the sidechain input to control the compression on a keyboard part, ensuring the guitar cuts through during its phrases.
• De-essing with Sidechain: Sidechain compression is applied to control sibilance in vocals by using a de-esser as the sidechain input. This reduces harsh “s” and “sh” sounds without affecting the overall vocal level.

4. Setting Up Sidechain Compression:

• Choose the Source and Target Tracks: Identify the track you want to affect (target) and the track whose amplitude will control the compression (source or sidechain input).
• Insert a Compressor on the Target Track: Insert a compressor on the target track. Most digital audio workstations (DAWs) allow you to engage sidechain functionality within the compressor plugin.
• Activate Sidechain Input: Enable the sidechain input on the compressor and select the source track as the input. Adjust any settings specific to sidechain, such as filter options.
• Adjust Compression Settings: Set the compression parameters (threshold, ratio, attack, release) based on the desired effect. The compressor will now respond to the amplitude changes of the sidechain input.
• Fine-Tune and Experiment: Experiment with different compression settings to achieve the desired result. Pay attention to how the elements interact in the mix, and fine-tune the sidechain compression to enhance clarity and balance.

5. Common Mistakes to Avoid:

• Overdoing It: Applying excessive compression or extreme settings can result in an unnatural or overly pronounced effect. Use subtlety for more transparent and musical results.
• Ignoring Timing Considerations: Pay attention to the timing of the attack and release settings. Improper timing can result in pumping artifacts or an unnatural feel.

De-essing:

Purpose: Targets and reduces sibilant sounds (e.g., “s” and “sh” sounds).

Application: Commonly used on vocal tracks to control harsh or piercing frequencies.

De-essing is a specific form of dynamic processing used in music production to reduce or control excessive sibilance in vocal recordings. Sibilance refers to harsh “s” and “sh” sounds that can be distracting or overly prominent in vocal tracks.

1. Understanding De-essing:

• De-essing is a process that specifically targets and attenuates the frequencies associated with sibilant sounds in a vocal performance. It is a form of frequency-selective compression designed to address the transient peaks caused by sibilant consonants.

2. Purpose of De-essing:

• The primary purpose of de-essing is to control and reduce the intensity of sibilant frequencies in a vocal recording. By selectively compressing or attenuating these frequencies, de-essing helps achieve a more balanced and pleasant vocal sound without sacrificing the overall clarity of the voice.

3. Applications of De-essing:

• Vocal Tracks: De-essing is commonly applied to vocal tracks to tame excessive sibilance, making the vocals more pleasant and intelligible.
• Dialog in Film and Podcasts: De-essing is used in audio post-production for film and podcasts to enhance the clarity of spoken dialogue by reducing sibilance.
• Overheads and Hi-Hats: In drum recordings, de-essing can be applied to control sibilance from hi-hats and cymbals, providing a smoother and more balanced drum sound.

4. Using De-essing Effectively:

• Identify Sibilant Frequencies: Listen to the vocal track and identify the specific frequencies associated with sibilant sounds. Common sibilance frequencies range from 4 kHz to 10 kHz.
• Select a De-esser Plugin: Choose a dedicated de-esser plugin or use a dynamic equalizer with a sidechain feature to apply de-essing. Many digital audio workstations (DAWs) come with built-in de-esser plugins.
• Set the Threshold: Adjust the threshold parameter to determine when the de-esser engages. It should be set so that it activates specifically during sibilant sounds.
• Adjust the Frequency Range: Specify the frequency range that the de-esser will target. This range should cover the frequencies responsible for sibilance without affecting the natural tonality of the vocals.
• Fine-Tune Attack and Release: Experiment with the attack and release times to achieve a balance between effectively reducing sibilance and avoiding unnatural artifacts. A faster attack time is generally preferred to catch transient sibilant peaks.
• Monitor and Adjust: Constantly monitor the vocal track while adjusting the de-esser settings. Listen for any artifacts or unnatural changes in the vocal tone, and make fine-tune adjustments as needed.

5. Common Mistakes to Avoid:

• Over-de-essing: Applying too much de-essing can result in a dull or lispy vocal sound. Use moderation to maintain a natural and transparent result.
• Ignoring Context: Consider the style and genre of the music. Some genres tolerate more sibilance than others, and complete elimination may not be desirable.

Limiting:

Purpose: Sets an absolute ceiling on the signal’s level.

Application: Prevents signals from exceeding a certain level, often used for mastering to maximize loudness.

Limiting is a dynamic processing technique in music production used to control the peak levels of audio signals. It involves setting an absolute ceiling on the amplitude of a signal, preventing it from exceeding a certain level

1. Understanding Limiting:

• Limiting is a type of compression that specifically focuses on preventing the audio signal from exceeding a predefined threshold. Unlike traditional compression, which can allow for some level of signal above the threshold, a limiter’s primary goal is to act as a safety net, ensuring that the signal does not surpass a specified amplitude.

2. Purpose of Limiting:

• The primary purpose of limiting is to control and restrict the peak levels of audio signals. This is crucial for preventing distortion, clipping, and ensuring that the audio stays within the acceptable limits of playback systems and media formats.

3. Applications of Limiting:

• Mastering: Limiting is commonly applied during the mastering stage to maximize the overall loudness of a track without introducing clipping or distortion. It helps achieve a competitive and consistent volume level across different tracks.
• Preventing Clipping: In digital audio, exceeding the maximum amplitude can lead to clipping, which results in distortion. Limiting is used to set a hard ceiling, preventing the signal from going above this threshold.
• Dynamic Range Control: Limiters are used to control dynamic range, ensuring that the softer parts of a mix are brought up in volume without allowing the louder elements to clip.

4. Using Limiting Effectively:

• Set the Threshold: Choose the threshold level at which the limiter engages. This level should be determined by the desired output level and the technical specifications of the playback system or media format.
• Adjust Attack and Release: Adjust the attack and release times to control how quickly the limiter responds to peaks and recovers after attenuation. For limiting during mastering, a fast attack time and a moderate release time are often suitable.
• Use Look-Ahead Functionality: Some limiters offer a look-ahead feature that allows the limiter to anticipate peaks before they occur. This can be useful for preventing transients from causing clipping.
• Apply Makeup Gain: After limiting, apply makeup gain to bring the overall level of the signal back to an appropriate loudness. Be cautious not to overdo it, as excessive gain may lead to artifacts or a loss of dynamic range.
• Use Multiband Limiting: Some limiters offer multiband functionality, allowing you to set different limiting parameters for different frequency bands. This can be useful for addressing specific frequency-related issues.

5. Common Mistakes to Avoid:

• Over-Limiting: Applying too much limiting can result in a loss of dynamics, a flattened sound, and audible distortion. Use limiting judiciously to achieve the desired loudness without sacrificing the integrity of the mix.
• Ignoring Artifacts: Listen for any unwanted artifacts introduced by the limiter, such as pumping or distortion. Adjust settings accordingly to minimize these artifacts.

Dynamic EQ:

Purpose: Applies EQ adjustments based on the dynamic characteristics of the input signal.

Application: Allows for frequency-specific compression or expansion.

Dynamic EQ is a versatile and advanced equalization tool in music production that combines the features of traditional equalization with dynamic processing. Unlike static EQ, which applies fixed frequency adjustments, dynamic EQ responds dynamically to the changing levels of specific frequencies.

1. Understanding Dynamic EQ:

• Dynamic EQ combines the precision of parametric equalization with dynamic processing features such as threshold, ratio, attack, and release. This allows the EQ to respond dynamically to changes in the input signal, applying boosts or cuts only when certain frequencies exceed a specified threshold.

2. Purpose of Dynamic EQ:

• The primary purpose of dynamic EQ is to selectively address frequency-related issues in a dynamic and targeted manner. It can be used to control specific frequencies only when they become problematic, offering more flexibility and transparency than traditional static EQ.

3. Applications of Dynamic EQ:

• Taming Resonances: Dynamic EQ is effective in taming resonant frequencies that may vary in intensity throughout a performance. It applies cuts only when those frequencies become excessive.
• De-essing: Dynamic EQ is used for de-essing by reducing the intensity of sibilant frequencies in vocals dynamically, responding to the varying level of sibilance in the performance.
• Instrumental Balancing: It can be applied to balance the tonal characteristics of instruments, dynamically addressing certain frequency imbalances only when they occur.
• Controlling Low-End Issues: Dynamic EQ is useful for controlling low-end issues, such as excessive bass frequencies during certain parts of a performance or mix.

4. Using Dynamic EQ Effectively:

• Identify Target Frequencies: Listen to the audio and identify the specific frequencies you want to address dynamically. This could be problematic resonances, sibilant frequencies, or other tonal imbalances.
• Set Threshold and Ratio: Set the threshold to determine when the dynamic EQ will engage, and adjust the ratio to control the intensity of the applied EQ. A higher ratio results in more aggressive dynamic equalization.
• Adjust Attack and Release: Experiment with the attack and release times to control how quickly the dynamic EQ responds to changes in the input signal. Faster attack times can capture transients, while slower release times provide a smoother response.
• Fine-Tune Q (Bandwidth): Adjust the Q or bandwidth parameter to control the width of the frequency band affected by the dynamic EQ. A narrower Q focuses on a specific frequency, while a broader Q affects a wider range.
• Monitor and A/B Test: Constantly monitor the effect of the dynamic EQ on the signal and use A/B testing to compare the processed and unprocessed versions. This helps ensure that the dynamic EQ enhances the sound without introducing unwanted artifacts.

5. Common Mistakes to Avoid:

• Over-Processing: Applying excessive dynamic EQ can lead to unnatural artifacts or a sterile sound. Use moderation to address specific issues without over-processing.
• Ignoring Context: Consider the musical context when applying dynamic EQ. Different genres and styles may require varying levels of dynamic control.

Vintage Compression (Analog Emulation):

Purpose: Emulates the characteristics of classic analog compressors.

Application: Adds warmth, color, and character to the audio signal.

Vintage compression, often achieved through analog emulation plugins, is a sought-after technique in music production that aims to replicate the warm, colorful, and character-rich sound associated with classic analog compressors.

1. Understanding Vintage Compression:

• Vintage compression refers to the sonic characteristics imparted by classic analog compressors that were prevalent in recording studios during the mid-20th century. These compressors, often hardware units, are known for introducing subtle harmonic distortion, coloration, and a distinct “musical” quality to the audio signal.

2. Purpose of Vintage Compression:

• The primary purpose of vintage compression is to add warmth, character, and a sense of “glue” to the audio signal. Vintage compressors are valued for their ability to impart a unique sonic fingerprint, enhancing the musicality of a mix or individual tracks.

3. Applications of Vintage Compression:

• Drum Buss: Vintage compression is often applied to the drum buss to add cohesion, warmth, and a sense of analog saturation to the overall drum mix.
• Vocals: Vintage compressors can impart a smooth and musical quality to vocals, enhancing the richness of the sound and controlling dynamics in a pleasing way.
• Bass: Applying vintage compression to bass tracks can add sustain, warmth, and a subtle grit, contributing to a more pronounced and present bass sound.
• Mix Bus: Vintage compression is commonly used on the mix bus during mastering to impart an overall analog coloration to the entire mix.

4. Using Vintage Compression Effectively:

• Selecting the Right Plugin: Choose a vintage compression plugin that emulates the characteristics of classic analog compressors. Many plugins specifically model well-known hardware units such as the LA-2A, 1176, or Fairchild.
• Understanding Knob Parameters: Vintage compressors often have simple controls such as Input, Output, Ratio, and Release. Familiarize yourself with the nuances of each parameter to achieve the desired compression characteristics.
• Embrace Saturation and Harmonic Distortion: Vintage compression is not only about dynamic control but also about introducing harmonic distortion and saturation. Experiment with different settings to find the sweet spot that adds warmth without overdoing it.
• Set and Forget: Vintage compression plugins are often designed to be set and left alone, requiring minimal adjustment once you find the right settings. Trust your ears and avoid unnecessary tweaking.
• Parallel Processing: Consider using vintage compression in parallel (mixing the compressed and uncompressed signals) to retain the natural dynamics of the original signal while benefiting from the warmth and coloration of the compressor.