Creating a professional-sounding podcast is more than just having a great voice and compelling content. Background noise, hums, clicks, and hisses can instantly undermine your credibility and distract listeners. Fortunately, noise reduction plugins are powerful tools that can clean up your audio without requiring a costly studio. This guide dives deep into how to use these plugins effectively, from understanding the science behind noise reduction to applying advanced techniques for pristine podcast audio.

Understanding the Different Types of Noise in Podcast Recordings

Before you can effectively remove noise, you need to identify what kind of noise you're dealing with. Different audio problems require different approaches, and not all noise reduction plugins handle every type equally well.

Consistent Background Noise

This is the most common culprit. It includes the hum from air conditioning units, fans, computer fans, traffic outside, or the low rumble of heating systems. Consistent noise is often steady-state, meaning it has a constant frequency and amplitude. This type of noise responds well to plugins that use a noise print – a sample of just the noise that the plugin learns to subtract.

Intermittent or Transient Noise

Clicks, pops, microphone bumps, keyboard typing, paper rustling, and other sudden sounds fall into this category. These are harder to remove because they don't have a predictable pattern. Specialized plugins like iZotope RX’s De-click or De-clip are designed for these specific artifacts.

Reverb and Echo

Room reverb makes your voice sound distant or like you’re speaking in a bathroom. While not “noise” in the traditional sense, it can be equally distracting. Some advanced plugins include de-reverb modules, but the best solution is still acoustic treatment during recording.

Electrical Hum and Hiss

60 Hz hum (or 50 Hz in some regions) from poorly shielded cables or ground loops is a common problem. Hiss often comes from high gain on microphones or preamps. Many noise reduction plugins include notch filters or specific hum removal algorithms.

How Noise Reduction Plugins Work

Understanding the underlying technology helps you use these tools more intelligently. Most noise reduction plugins rely on one or a combination of the following techniques:

Noise Print Analysis (Subtractive Method)

You select a segment of audio containing only the noise (no speech, no music). The plugin analyzes the frequency profile and then subtracts that profile from the entire track. This method works excellently for steady-state noise but can introduce “musical noise” artifacts if overused.

Spectral Editing

Advanced tools like iZotope RX display audio as a visual spectrogram. You can literally draw around unwanted sounds – a car horn, a cough, a siren – and remove them with surgical precision. This is the most powerful but also the most manual method.

Noise Gates and Expanders

A noise gate silences audio when it falls below a certain threshold. This is useful for removing background noise during pauses in speech, but it won’t clean noise that happens while you’re talking. An expander works similarly but reduces noise gradually instead of cutting it off abruptly.

Real-Time vs. Offline Processing

Some plugins like Waves NS1 work in real-time, meaning you can monitor the effect as you record or play back. Others, like Audacity’s built-in Noise Reduction, require offline processing where you apply the effect and then render the audio. Real-time plugins are convenient for live streaming, but offline processing often yields higher quality because the plugin can analyze the entire file at once.

Choosing the Right Plugin for Your Workflow

There is no one-size-fits-all plugin. Your choice depends on your budget, technical skill, and the specific types of noise you encounter.

iZotope RX – The Industry Standard

iZotope RX is the gold standard for professional audio cleanup. It comes in several editions (Elements, Standard, Advanced) with increasing features. The core modules include Mouth De-click, De-hum, De-noise, Spectral De-noise, and Voice De-noise. It integrates with most DAWs and can be used as a standalone editor. RX Advanced even includes machine-learning-powered tools like Dialog Isolate. This is the go-to for podcasters who demand the cleanest possible audio.

External Link: iZotope RX Official Site

Waves NS1 – Simplicity and Speed

If you want a one-knob solution that works in real-time, Waves NS1 is hard to beat. It uses a neural network trained to separate speech from noise. You simply dial in the amount of reduction (typically between 50-70%) and it handles the rest. It requires very little manual tweaking and works well on consistent, moderate background noise. However, on extreme noise or unusual sounds, it can occasionally over-process and make voices sound slightly phasey.

External Link: Waves NS1 Noise Suppressor

Accusonus ERA Bundle – Versatile and Fast

The ERA bundle from Accusonus includes individual one-knob plugins for specific noise types: Noise Remover, Plosive Remover, De-esser, De-clipper, and more. The advantage is that you can chain them together for targeted cleanup. The voice-activated processing adapts to speech, reducing the risk of artifacts. The ERA Noise Remover (now often called Supertone Clear) is particularly good for removing consistent background hum and fan noise.

External Link: Supertone Clear (formerly Accusonus ERA)

Audacity Noise Reduction – Free and Effective

For beginners or those on a tight budget, Audacity’s built-in Noise Reduction effect is remarkably capable. It uses the same subtractive noise print method found in expensive plugins. The learning curve is slightly steeper because you have to manually adjust parameters like Noise Reduction (dB), Sensitivity, and Frequency Smoothing Bands. With careful tweaking, you can achieve good results. The main downside is that it can produce robotic artifacts if pushed too hard, and it lacks the spectral editing features of paid tools.

External Link: Audacity Official Site

Other Notable Plugins

  • Clarity Vx (by Waves): A dedicated de-noise plugin for dialogue, using deep learning. Very good with natural-sounding results.
  • Brusfri (by Klevgrand): A budget-friendly option that does an excellent job on steady noise with a simple interface.
  • ReaFIR (Reaper built-in): Included with Reaper, this plugin offers similar functionality to Audacity’s noise reduction but with more control.

Step-by-Step Guide: Using Noise Reduction Plugins Effectively

Now let’s walk through a practical workflow that you can apply in any DAW (Audacity, Reaper, Logic Pro, Adobe Audition, etc.).

Step 1: Record in the Best Possible Environment

Noise reduction is about cleanup, not magic. Always aim to capture the cleanest audio possible. Record in a quiet room, use a dynamic microphone if your space is not treated, avoid placing the microphone near computer fans or air vents, and speak at a consistent distance. You can also use a simple reflection filter to reduce room reverb.

Step 2: Identify the Noise Profile

Look for a section of your recording that contains nothing but background noise – typically a pause between sentences, the beginning or end of a track, or a deliberate moment of silence. Highlight this clip (1-3 seconds is usually enough). This is your noise print. In Audacity, go to Effect > Noise Reduction and click “Get Noise Profile.” In iZotope RX, select the region and click “Learn” under De-noise.

Step 3: Apply Initial Broad-Stroke Reduction

Select the entire audio track (or the region you want to clean) and apply the noise reduction effect. For consistent noise, start with a moderate reduction level – around 15-20 dB in Audacity or 50-60% in a plugin like NS1. Listen critically for artifacts. If the voice sounds thin or watery, you’ve overdone it. Reduce the amount and try again.

Step 4: Target Specific Noises with Dedicated Tools

After removing the general background hum, focus on the remaining problematic sounds. This is where spectral editing or multi-module processing shines.

  • For clicks and pops: Use a De-click plugin (e.g., iZotope RX De-click, Accusonus ERA De-click). These automatically detect and repair transient discontinuities.
  • For mouth noises (smacks, clicks): A specialized Mouth De-click plugin is highly effective. iZotope RX Elements includes this; Audacity users can try the spectral selection – highlight the click in the spectrogram view and use the “Repair” effect to patch it.
  • For electrical hum: Use a De-hum plugin or a notch filter. In Audacity, the “Notch Filter” effect can target 60 Hz (and its harmonics) precisely.
  • For reverb: Use a De-reverb module. iZotope RX Advanced has one, or you can try a transient shaper to reduce the reverb tail. But remember: this is the hardest thing to fix after the fact.

Step 5: Use a Noise Gate to Clean Silences

Between your words, there will be residual noise that the subtractive reduction didn’t fully remove. A noise gate silences these gaps. Set the threshold just above the noise floor (use the level meters to identify the noise level). Adjust the attack time to be very fast (1-5 ms) so the gate opens instantly when you start speaking. The release time should be set to 50-100 ms to avoid abrupt cutoffs. In many DAWs, a noise gate is included as a stock plugin.

Step 6: Fine-Tune and A/B Compare

Always compare the processed audio with the original to ensure you haven’t degraded the quality. Most plugins have a bypass button. Listen particularly to the sibilance (S and T sounds) – noise reduction can sometimes dull these frequencies. If you hear artifacts, try:

  • Lowering the reduction amount.
  • Increasing the frequency smoothing (spread the reduction over more bands).
  • Applying a gentle EQ to restore high-frequency clarity after noise reduction.

Step 7: Render and Check in Context

Apply the effect and render the clip. Then listen to the cleaned audio in the context of your full podcast episode. Sometimes a piece of noise that seemed loud in isolation is actually masked by music or other background sounds. Conversely, a very aggressive reduction might make your voice sound processed. Trust your ears over the visual meters.

Common Mistakes and How to Avoid Them

Even experienced podcasters can fall into these traps. Here’s what to watch out for:

  • Over-cleaning: Removing too much noise can make the audio sound hollow, underwater-like, or “phasey.” It can also introduce musical artifacts (warble tones). Always apply noise reduction with a light touch and layer multiple small reductions rather than one heavy pass.
  • Using the wrong noise profile: If your noise print includes any voice or musical content, the plugin will try to remove those frequencies too, wrecking your audio. Select only pure noise sections.
  • Ignoring low-frequency rumble: Many podcasters forget about subsonic rumble (below 80 Hz). A simple high-pass filter (HPF) can often clean up low-end noise without any specialized plugin. Set it around 80-100 Hz for male voices, lower for females if needed.
  • Not backing up the original: Always keep a raw, unprocessed copy of your recording. If you make a mistake and need to start over, you’ll be grateful you have the original. Use a non-destructive workflow when possible (e.g., use a plugin on an audio track rather than rendering destructive changes).
  • Relying only on plugins: No plugin can fix a terrible recording. If your audio is distorted (clipping), has severe reverb, or sounds like it was recorded in a windstorm, no amount of digital cleanup will save it. Re-record if possible.

Advanced Techniques for Crystal-Clear Podcast Audio

Once you’ve mastered the basics, these advanced tips can push your audio quality even further.

Use Multiple Stages of Reduction

Instead of one massive noise reduction pass, consider a three-stage approach:

  1. Stage 1: Broad subtraction of the noise floor using a noise print (Audacity, RX, BRusfri). Aim for removal of about 6-10 dB of noise.
  2. Stage 2: Clean up remaining intermittent noises: clicks, mouth sounds, umms, breaths (optional – some breaths can be natural). Use a De-clicker.
  3. Stage 3: Apply a gentle noise gate to silence the gaps between spoken words.

Combine with EQ for Natural Sound

Noise reduction can sometimes make voices sound a bit dull or boxy. After processing, use a parametric EQ to restore some presence. Typically, a slight boost around 3-5 kHz can add clarity, and a gentle high shelf above 8 kHz can bring back air. But don’t overdo it – you’ll also bring up any remaining noise.

Use Spectral Editing Manually

For stubborn short-duration noises (a dog bark, a car horn), tools like iZotope RX’s Spectrogram allow you to literally paint over the sound and have it replaced with surrounding audio texture. This is surgical and can save an otherwise unusable clip. In Audacity, you can select a small region in the spectrogram view and use the “Repair” effect, though it’s less sophisticated.

Automate Your Noise Reduction

If your podcast has varying levels of background noise (e.g., a noisy segment recorded at a different location), use automation to change the plugin parameters over time. In your DAW, you can automate the threshold of a noise gate or the amount of reduction in a de-noise plugin as the background noise changes.

Conclusion: Clean Audio, Professional Podcast

Noise reduction plugins are not a substitute for good recording practices, but they are an essential part of a modern podcast workflow. By understanding the type of noise you’re dealing with, choosing the right plugin for the job, and applying a careful, step-by-step process, you can elevate your audio from amateur to professional. Start with a free tool like Audacity to learn the basics, then experiment with advanced solutions like iZotope RX or Waves NS1 as your skills grow. Your listeners will thank you for providing a crisp, distraction-free experience.

Remember: the goal is not to eliminate every microbe of noise, but to achieve a natural, clean sound that keeps the focus on your content. With the techniques in this guide, you’re well on your way to producing a podcast that sounds as good as it is informative.