How to Use the Limiter Effect in Audacity

The Limiter effect in Audacity is an essential dynamics processing tool designed to prevent your audio from exceeding a set volume ceiling, eliminating harsh digital clipping and distortion. This guide explains how to locate the Limiter, configure its settings to establish an absolute volume threshold (such as -1.0 dB or -0.5 dB), and apply it cleanly to individual tracks or fully mastered projects.

Step 1: Select Your Audio Track

1. Open your project in Audacity.
2. Select the portion of the audio you want to limit. To apply it to an entire track, click the track header on the left or press Ctrl + A (Windows) or Cmd + A (Mac) to select all tracks.

Step 2: Open the Limiter Effect

1. Navigate to the top menu and click Effect.
2. Go to Volume and Compression and select Limiter (in older versions of Audacity, it is listed directly under the Effect menu).

Step 3: Configure the Limiter Parameters

Adjust the sliders in the Limiter dialog box to control how peaks are restricted:

• Type: Choose the limiting behavior.
  • Hard Limit: Cuts off peaks instantly at the specified threshold. It is the most effective choice for preventing clipping, especially for podcasts, audiobooks (ACX standards), and broadcast audio.
  • Soft Limit: Applies a rounded curve as peaks approach the ceiling, creating a more subtle, transparent result suitable for acoustic or dynamic music.
• Input Gain (Mon/Left and Right): Leave this set to 0.00 dB unless your entire signal is already too quiet and needs boosting before it reaches the limiter.
• Limit to (dB): This is your maximum ceiling. Set this value to the highest peak level you will permit. For standard mastering and online distribution, set this to -1.0 dB or -0.5 dB to prevent inter-sample clipping during MP3 or AAC conversion.
• Hold (ms): Determines how long the limiter remains active after a peak is detected. A default value between 2.00 ms and 10.00 ms prevents low-frequency distortion while keeping the attenuation natural.
• Apply Make-up Gain: Set this to No if your only objective is capping peaks at your designated ceiling. Setting this to "Yes" will boost the entire track so the limited peaks reach 0 dB, which defeats the purpose of keeping audio below a lower target ceiling.

Step 4: Preview and Apply

1. Click Preview in the bottom-left corner to ensure the processing does not introduce noticeable pumping or distortion.
2. Click Apply.

Audacity will render the changes. You will see that the audio waveforms no longer extend beyond the ceiling value you set, ensuring the final output stays safely below your specified limit.