What Are Plosives and Sibilance?

Plosives occur when a sudden burst of air from consonant sounds like p, b, t, and d strikes the microphone diaphragm. The resulting low-frequency thump or pop can overload the preamp and muddy the mix. Sibilance, by contrast, refers to exaggerated high-frequency fricatives—primarily s, sh, ch, and z—that become harsh or piercing. Both issues stem from the physics of air movement and microphone design, but with deliberate technique they can be effectively managed.

Understanding the acoustic causes is the first step. Plosives generate a transient pressure wave that can displace the diaphragm beyond its linear range, causing distortion. Sibilance arises from turbulent airflow across the teeth and tongue, which produces a concentrated burst of high-frequency noise. The microphone’s proximity and axis determine how much of this energy is captured. Even the best vocalists produce these sounds naturally; the goal is to minimize their impact on the recording without sacrificing the natural character of the voice.

Techniques for Reducing Plosives

Plosives are easier to prevent than to fix. The key is disrupting the direct air stream before it hits the microphone diaphragm. Below are the most reliable methods, ranging from hardware to positioning and performance.

Use a Pop Filter

A pop filter—typically a fine mesh screen or perforated metal disk placed 2–4 inches from the microphone—disperses the energy of plosive bursts. The filter allows sound waves to pass while blocking the physical air blast. For optimal results, ensure the filter is large enough to cover the microphone’s capsule and is positioned so the vocalist does not inadvertently touch it during performance. There are two main types: nylon mesh filters are affordable and effective, while metal mesh filters offer better durability and less high-frequency attenuation. Some engineers prefer a double-layer design for extra protection. Always angle the filter slightly to avoid creating a resonant cavity between the filter and the microphone.

Optimize Microphone Placement

Angle and distance matter greatly. Instead of singing directly into the center of the capsule, position the microphone slightly off-axis—oriented about 15–30 degrees to the side of the mouth. This offset prevents air from hitting the diaphragm head-on. Additionally, maintaining a distance of 6–12 inches reduces the force of any residual air burst. For extreme cases, consider placing the microphone slightly above or below the mouth line, though be mindful of changes in tone and proximity effect. The proximity effect boosts low frequencies when the source is close; moving the mic off-axis can tame this as well. Experiment with a combination of distance and angle to find the sweet spot where plosives disappear without losing vocal presence.

Employ a Windscreen

Foam windscreens (often called “dead cats” for outdoor use) can be slipped over the microphone capsule. While less precise than a pop filter, they offer decent plosive reduction and are particularly useful for handheld or mobile recording setups. They also protect the capsule from saliva and dust. Note that windscreens may slightly attenuate high-frequency detail, so test them with your specific microphone. Some high-end foam windscreens are designed with open-cell foam that minimizes high-frequency loss. For studio use, a combined approach—pop filter plus windscreen—can be overkill but may be necessary for very breathy singers or outdoor recording.

Coach Vocal Technique

The most elegant solution involves the performer. Encourage vocalists to practice articulating plosive consonants with less explosive breath energy. For example, a “p” can be softened by relaxing the lips or by angling the head slightly away from the mic during those syllables. Many experienced singers instinctively lean back from the microphone on hard consonants. In a recording session, small adjustments can yield dramatic reductions in plosive artifacts. A simple trick is to have the vocalist use a handheld pop filter as a reference: they can touch it with their lips to feel the distance and then maintain that distance while singing. For voiceover work, training the talent to “spit” plosives with reduced air pressure can eliminate the need for heavy post-processing.

Select a Microphone with Built-in Rejection

Some microphones are inherently less sensitive to plosives. Large-diaphragm condensers with built-in pop protection or those designed with an internal mesh grid (like the Shure SM7B) offer natural resistance. Ribbon microphones, due to their bidirectional pickup pattern, can also help if positioned correctly, though they require careful handling to avoid damage from air blasts. Dynamic microphones like the Electro-Voice RE20 feature a built-in pop filter and are standard in broadcast for this reason. When choosing a microphone, listen to how it handles plosives in your specific room and with your vocalist. A microphone that rejects plosives well may also reduce the need for additional hardware.

Techniques for Reducing Sibilance

Sibilance is a high-frequency issue, typically peaking between 5 kHz and 8 kHz. While some sibilance is natural and even desirable for intelligibility, excessive amounts can be fatiguing. The goal is taming the harshness without dulling the overall vocal tone.

Microphone Selection and Positioning

Not all microphones capture sibilance equally. Condenser mics with a pronounced high-frequency presence peak (e.g., many budget large-diaphragm mics) can exaggerate sibilance. In contrast, dynamic mics or ribbon mics often produce a smoother top end. Positioning the microphone slightly above or below the mouth axis—rather than directly in front—reduces the direct capture of sibilant air turbulence. Experimentation is key: a 10-degree change can shift the balance. Some engineers use a high-pass filter on the microphone preamp before the signal hits the converter to cut some low-end rumble, but this does not address sibilance. Instead, try a presence cut of 1–2 dB at 5 kHz using the preamp’s EQ if available.

De-essing During Tracking or Mixing

De-essing is the targeted reduction of sibilant frequencies. This can be done with a dedicated hardware de-esser, a plugin, or even a multiband compressor set to the 5–8 kHz range. For tracking, it’s often better to record without de-essing to retain flexibility, but a gentle touch during monitoring can guide performance. In mixing, use a de-esser with sidechain filtering so it only activates on sibilant content, leaving the rest of the vocal unprocessed. Adjust the attack and release times to preserve natural transients. Most de-esser plugins offer a threshold control and a frequency band selector; start with a narrow band centered around 6 kHz and set the threshold so it triggers only on the loudest “s” sounds. A fast attack (0.5–2 ms) and a moderate release (10–50 ms) usually work well. For more detailed guidance, refer to Sound On Sound’s de-essing guide which explains sidechain techniques in depth.

Equalization (EQ)

A surgical EQ cut in the problematic frequency band can attenuate sibilance. Use a narrow Q (high resonance) and sweep between 5–8 kHz to find the offending peak. A cut of 2–4 dB is often sufficient. Be cautious not to overdo it, as excessive reduction can make vocals sound lispy or muffled. Pairing EQ with de-essing yields more transparent results. Some engineers prefer a dynamic EQ that only cuts when sibilance exceeds a threshold, which is essentially a de-esser but with a more transparent sound. For example, FabFilter Pro-Q 3’s dynamic EQ mode can be tuned to the sibilant frequency and set to reduce gain only when the signal is loud enough, preserving natural high-frequency detail.

Compression and Multiband Compression

Standard compression can inadvertently emphasize sibilance because it boosts quieter high-frequency content. To avoid this, use a multiband compressor on the high-frequency band only. Set a low threshold so only the loudest sibilant spikes trigger compression, with a fast attack (1–5 ms) and moderate release (50–100 ms). This smooths the harshness without affecting other high-frequency detail like breathiness or air. In a multiband compressor, solo the band centered around 6 kHz, adjust the crossover points to isolate the sibilance region, and set the ratio to 2:1 or 3:1. Use the make-up gain to compensate for any level loss. This technique is especially effective when sibilance varies throughout the performance, as it reacts dynamically.

Vocal Technique Adjustments

Singers and voice actors can modify their enunciation to reduce sibilance. For example, directing the tongue slightly lower during “s” sounds—or reducing the length of the sibilant—can lower the intensity. Some vocalists also change their distance or angle on the fly. Ear training for both performer and engineer helps identify problematic moments and correct them at the source. In a session, have the vocalist practice the phrase with the “s” sounds softer, almost like a lisp without the distortion. Record a few takes with exaggerated sibilance and a few with reduced sibilance, then compare to find the natural balance. Over time, the vocalist can internalize these adjustments.

Post-Production Workflow Summary

In the mixing stage, follow a systematic approach:

  1. Listen critically for plosives and sibilance across the entire vocal track. Mark regions where they are prominent.
  2. Apply corrective EQ or dynamic processing first. For plosives, a high-pass filter around 50–80 Hz can remove the low-end thump while preserving vocal body. For sibilance, use a de-esser with sidechain EQ tuned to 5–8 kHz.
  3. Audition in context with the mix. Sometimes sibilance masks itself in a dense arrangement; other times it becomes more apparent. Adjust processing accordingly.
  4. Consider manual editing for extreme cases: clip gain reduction on individual syllables or fade handles on plosive transients.
  5. Final check through headphones and speakers to ensure naturalness.

Advanced Techniques for Both Issues

Combination Approaches

Often plosives and sibilance occur together, requiring multifaceted solutions. Use a pop filter for plosives and a de-esser plugin for sibilance, but also check your room acoustics. Reflective surfaces can exacerbate sibilance by creating comb filtering. Treat the recording space with absorbers near the microphone to dampen problematic reflections. Additionally, a high-pass filter on the microphone preamp (around 80 Hz) helps remove low-frequency plosive energy before it hits the converter. For live streaming or podcasting, some audio interfaces include built-in de-essing and high-pass filters—take advantage of these if available.

Multiple Microphones and Blending

In critical applications, engineers sometimes use two microphones: one close (for detail, with pop protection) and one at a distance (to capture a more rounded tone). By blending the two, they can reduce the impact of both plosives and sibilance from the close mic, while the distant mic provides natural air. This requires careful phase alignment but can yield extremely clean vocals. A common setup is a large-diaphragm condenser close and a small-diaphragm condenser or ribbon at a few feet. Use a phase alignment tool (like Auto-Align) to ensure the signals sum constructively. The blend ratio might be 70% close and 30% distant, adjusted to taste.

Spectral Editing in Post-Production

Advanced software like iZotope RX or Adobe Audition’s spectral editing allows visual identification and removal of plosive clicks and sibilant spikes. You can literally draw around the offending artifact and attenuate it with minimal effect on surrounding audio. This technique is particularly useful for repairing problematic takes that could not be re-recorded. In iZotope RX, the “De-plosive” module automatically detects and removes plosive bursts, while the “De-esser” module handles sibilance. For manual control, use the Spectral Repair tool with the “Attenuate” or “Replace” mode. Avid’s resource on de-esser and plosive removal provides step-by-step instructions for Pro Tools users.

Room Acoustics and Microphone Placement

The recording environment plays a significant role in how plosives and sibilance are captured. Hard surfaces (walls, windows) create reflections that can reinforce sibilant frequencies. Place absorption panels at ear height and behind the vocalist to dampen early reflections. A reflection filter (such as the sE Electronics RF-X) placed behind the microphone can help isolate the capsule from room echoes. For plosives, a room with carpet and soft furnishings naturally diffuses air movement better than a tiled room. If you cannot treat the room, position the vocalist facing into a corner with absorption behind them to reduce standing waves.

Recording Level and Gain Staging

Proper gain staging reduces the impact of plosives and sibilance on subsequent processing. Set the preamp gain so the loudest peaks hit around -6 dBFS (for 24-bit recording). Plosive spikes may exceed this, causing clipping. A pad switch on the microphone or preamp can help. Some engineers use a compressor before the converter with a fast attack to catch plosive transients, but this can affect the vocal tone if set too aggressively. Alternatively, record with a limiter set to -1 dBFS to catch only the very top peaks; this is often used in broadcasting. Recording Revolution’s tips on sibilance reduction include gain staging advice.

Putting It All Together

Successful plosive and sibilance management requires a layered approach. Start with the best possible performance and technical setup: choose a microphone with appropriate rejection, apply a pop filter or windscreen, and position the mic off-axis at the correct distance. Coach the vocalist to adjust their technique. During recording, monitor for issues and make real-time adjustments. In post-production, use a combination of high-pass filtering, de-essing, EQ, and if needed, spectral editing. Always reference the final result on multiple playback systems—headphones, studio monitors, and car speakers—to ensure the processing translates well.

For further reading, Sound On Sound’s comprehensive de-essing guide and Avid’s Pro Tools-specific tutorial are excellent resources. Additionally, Recording Revolution’s practical tips offer quick wins for home studio engineers.

Conclusion

Mastering plosive and sibilance control is not about eliminating all natural variations—it’s about reducing artifacts that distract from the performance. By combining proper microphone technique, thoughtful hardware choices, vocal coaching, and precise post-processing, you can achieve vocal recordings that are clear, present, and comfortable to listen to. Experiment with the methods above, trust your ears, and remember that prevention is always more effective than repair. With practice, managing these common vocal pitfalls becomes an intuitive part of your production workflow.