How to Use Audacity Limiter for Broadcast Standards

Meeting peak standards for audiobooks and broadcast platforms is essential to ensure your audio is accepted without distortion or rejection. This guide explains how to configure and apply the built-in Limiter effect in Audacity as the final mastering step, allowing you to cap maximum peak levels at specific ceilings—such as -3.0 dB for ACX/Audible or -1.0 dB to -2.0 dB for broadcast—while preserving audio clarity.

Common Industry Peak Standards

Before applying a limiter, determine the exact target threshold required by your distribution platform:

• Audiobooks (ACX / Audible / Findaway Voices): Peaks must not exceed -3.0 dB.
• Television & Radio Broadcast (EBU R128 / ATSC A/85): True peaks generally must not exceed -1.0 dBFS to -2.0 dBFS.
• Podcasts / Streaming Services: Maximum peaks typically sit between -1.0 dB and -1.5 dB to prevent distortion during lossy file conversion (MP3, AAC).

Step-by-Step: Applying the Limiter in Audacity

The Limiter should always be the final effect in your processing chain, applied after EQ, noise reduction, and compression.

1. Select Your Track: Click inside the track panel or press Ctrl + A (Windows) or Cmd + A (Mac) to highlight the entire audio file.
2. Open the Limiter: Go to the top menu, click Effect, navigate to Volume and Compression, and select Limiter.
3. Select Limiter Type:
   • Choose Soft Limit for natural voice recordings and spoken word. This rounds off peaks smoothly without introducing harsh clipping artifacts.
   • Choose Hard Limit if you require an absolute brickwall ceiling where no transient whatsoever may slip through.
4. Set Input Gain: Leave Input Gain (Left) and Input Gain (Right) at 0.00 dB. You do not want to boost the incoming signal unless your overall audio is drastically under-amplified.
5. Set the Peak Ceiling ("Limit to (dB)"):
   • For ACX/Audiobooks: Enter -3.00.
   • For Broadcast/Streaming: Enter -1.00 or -2.00, depending on the network deliverable requirements.
6. Adjust Hold: Set the Hold (ms) between 2.00 ms and 10.00 ms. A value around 5.00 ms is standard for voice; it prevents distortion by giving low frequencies sufficient time to cycle before the limiter releases.
7. Disable Make-up Gain: Set Apply Make-up Gain to No. Enabling make-up gain boosts the entire track afterward, which can raise your audio back above your chosen target threshold.
8. Apply and Verify: Click Apply.

Verifying Compliance

Once processed, zoom into the highest peaks on your waveform or play back loud sections while watching Audacity’s playback meter. The meter should not exceed your specified ceiling. For audiobooks, run Audacity’s ACX Check plugin (or check via the Measure RMS / Contrast tools) to confirm that the peak value reads exactly at or below -3.0 dB.