Understanding Plosive Sounds in Depth

Plosives occur when a sudden burst of air from the mouth strikes the microphone diaphragm. The "p" and "b" sounds are the most common culprits because they involve complete closure of the lips followed by an explosive release of air. Even a gentle puff can cause a low-frequency thump that distorts the waveform and ruins an otherwise clean take. Understanding the physics behind these pops helps you choose the right preventive and corrective measures.

Microphones with large diaphragms (common in studio condenser mics) are especially sensitive to plosive blasts. The air pressure deforms the diaphragm more than intended, creating a loud, distorted spike. Dynamic microphones are somewhat less sensitive, but they still suffer from excessive air movement. The problem is compounded by close-miking techniques often used in podcasting to isolate the voice from room noise.

Preventive Techniques Before Recording

1. Invest in a Quality Pop Filter

A pop filter is a thin acoustic screen (usually nylon or metal mesh) placed between the speaker and the microphone. It physically breaks up the air jet without affecting the sound quality. Pop filters are inexpensive and easy to attach via a gooseneck clamp. For best results, position the filter about 2–3 inches from the microphone capsule. Avoid cheap fabric filters that can flatten high frequencies; look for double-layer designs or fine metal mesh that maintains clarity.

2. Master Microphone Positioning

The angle and distance of the microphone dramatically affect plosive susceptibility. The most effective position is slightly off-axis—pointing the microphone toward the corner of your mouth rather than dead center. A 45-degree angle reduces the direct air blast while capturing a natural voice tone. Keep the microphone 6–12 inches away; closer distances increase plosive risk. Also, raise the microphone so you speak across it rather than straight into the capsule. Many podcasters have success with the “ear-level” or “nose-height” technique: position the mic just beside your mouth pointing toward the chin.

3. Use a High-Quality Windscreen or Foam Cover

Foam windscreens fit over the microphone head and serve a similar purpose to pop filters but are more convenient for portable setups. However, foam can dull the high-end clarity, so choose a thin, open-cell foam designed for studio use rather than outdoor wind control. Some microphones come with built-in grilles that already reduce plosives slightly; adding a foam cover provides an extra layer. For condenser microphones in a home studio, a pop filter is generally better than a foam cover because it diffuses air without frequency coloration.

4. Adjust Your Vocal Technique

Believe it or not, changing how you pronounce plosive sounds can eliminate pops at the source. Practice “softening” your plosives by releasing a little air through the nose or reducing the force of the release. For example, say “pop” with a gentle puff instead of a hard blast. Another trick: direct your plosives downward toward your chest rather than straight out of your mouth. This takes practice but is the most natural and cost‑free fix. Record a few test words and listen back while adjusting your technique.

5. Choose the Right Microphone

Not all microphones handle plosives equally. Dynamic microphones (like the Shure SM7B or Rode PodMic) are inherently less sensitive to transients because of their moving‑coil design. Cardioid or supercardioid polar patterns reject sound from the sides and rear, but they still capture front‑on plosives. If you struggle with plosives despite good positioning, consider switching to a dynamic mic with a built‑in grille and internal pop screen. Many broadcast microphones are engineered specifically for close‑up speech.

Hardware Solutions for Studio and Field

Acoustic Panels and Room Treatment

While room treatment doesn’t directly remove plosives, it reduces reflections that can exaggerate the low‑frequency thump. Bass traps in corners absorb those low‑end pops, making them less jarring in the final recording. A well‑treated room lets you keep the microphone further away (12+ inches) without picking up echoes, which also reduces plosives.

Shock Mounts and Isolation

A shock mount physically decouples the microphone from vibrations, but vibrations aren’t plosives. However, if the microphone stand is shaky, the impact of your voice can cause low‑frequency rumble that mimics a plosive. A good shock mount ensures the mic stays steady and only picks up air‑borne sound. Combined with proper positioning, this reduces false pops.

Post‑Processing Techniques to Remove Plosives

Even with the best preventive measures, some plosive pops may slip through. Post‑processing can salvage a recorded track without re‑recording the entire episode. Here are the most effective methods, from quick fixes to surgical editing.

1. Spectral Editing

Advanced audio editors like Audacity (free) or Adobe Audition (paid) offer spectral frequency displays. Plosives appear as dark, low‑frequency bursts (typically below 100 Hz). Use the spectral selection tool to highlight the pop and reduce its level or delete it. This is more precise than a band‑pass filter because it retains the voice’s natural low end. In Audacity, go to View > Spectrogram and then use the Effect > Equalization to cut only the pop region.

2. Equalization (EQ) Cut

A high‑pass filter (HPF) set at 80–100 Hz can remove the low‑frequency thump of most plosives without affecting the voice. Apply the HPF globally on the entire track, but be cautious: male voices may lose warmth if cut too high. A gentler approach is to use a narrow EQ notch (Q factor around 3–5) at the specific frequency of the plosive (often around 50–70 Hz). Automate this EQ to activate only during plosive moments using volume automation or a dynamic EQ plugin.

3. De‑essing and De‑plosive Plugins

Some plugins are specifically designed to remove plosives. De‑essers (often used for sibilance) can be repurposed to target low‑frequency bursts if you adjust the frequency range and threshold. Dedicated de‑plosive tools like iZotope RX De‑plosive or the free Plosive Detector plugin automatically identify and attenuate pops. These are ideal for batch processing many episodes because they reduce manual work.

4. Manual Volume Reduction

If the plosive is isolated (a single “p” sound), you can manually reduce the volume of that small section. In your DAW, zoom into the waveform until you see the spike. Use the envelope tool (or clip gain) to lower the amplitude of the transient. Be careful not to make it sound abrupt; use a short fade‑in of 5–10 ms to smooth the transition. This technique gives you 100% control and preserves the rest of the audio.

5. Multiband Compression

Set up a multiband compressor to target low frequencies (e.g., 20–150 Hz) with fast attack and release times. When a plosive triggers the low band, the compressor reduces its level quickly, then recovers before the next word. This is a dynamic solution that works across the whole track without needing manual intervention. However, it can affect the low‑end consistency of your voice, so test the settings carefully.

Workflow Integration and Tips

Combine multiple strategies for best results. For example, use a pop filter and off‑axis positioning during recording, then apply a high‑pass filter and manually attenuate any leftover pops in post. Many podcasters create a template with these effects pre‑loaded so they don’t have to repeat the setup each episode.

  • Monitor with headphones while recording to catch plosives early. If you hear a pop, stop and adjust your mic position or repetition.
  • Record a few seconds of silence before speaking to get a clean noise floor; this makes spectral editing easier.
  • Use a gain staging practice: keep levels moderate (peaking around −6 dB) to avoid clipping the plosive transient.

Conclusion

Eliminating plosive sounds from your podcast recordings is achievable through a combination of preventive hardware, smart microphone technique, and precise post‑processing. Start with a pop filter and correct positioning; those two steps alone will remove 90% of plosive issues. For the stubborn pops, deploy spectral editing, EQ cuts, or dedicated de‑plosive plugins. By integrating these techniques into your regular workflow, you’ll deliver a polished, professional listening experience that keeps your audience focused on your content—not on distracting pops.