What Is A Limiter? How And When To Use Limiters

What Is A Limiter? How And When To Use Limiters

An audio limiter is an essential tool in your music production toolkit. This powerful effect acts like a security guard for your audio levels, keeping them below a specified range. 

A limiter's primary purpose is to control the peak levels of audio signals, preventing clipping and overload.

Limiters work by setting a maximum threshold, above which all audio signals are subjected to a significant reduction in gain. This process helps maintain clarity and prevents any harsh peaks.

By effectively employing limiters, you can boost a track's perceived loudness without saturation and maintain its sound quality.

This technique is used by audio engineers in various fields, from radio broadcasting to music production. It's one of my go-to tools in every production.

What Is a Limiter?

Basics of a Limiter

A limiter is an audio processing tool that prevents audio signals from exceeding a decibel level you set in the limiter. By setting a ceiling, you can protect the audio from distortion and clipping.

Think of a limiter as a more extreme form of a compressor; the compression ratio of a limiter is so high that practically no audio signal exceeds the set threshold. A limiter reduces the volume of the peaks, which can help maintain clarity and elevate quieter parts of the audio tracks you're applying the limiter on.

Adding a limiter can be particularly valuable in mastering processes, where you want to increase perceived loudness while preserving quality. 

The key features of a Limiter

• Threshold: Sets the level at which the limiter starts working.

• Attack Time: Determines how quickly the limiter responds to volume spikes.

• Release Time: Controls how long it takes for the limiter to stop affecting the audio.

Brickwall Limiter

A brickwall limiter is a powerful tool that acts as a hard stop, not allowing any signal past the threshold. The most common use for brick wall limiters is to ensure no clipping occurs in a track.

Sometimes digital limiters aren't automatically configured to catch inter-sample peaks; this is where true peak mode comes in handy. It makes sure that digital audio does not exceed the limiter's threshold when converted to an analog signal. 

True peak mode is especially useful for preventing distortion in streaming or broadcasting.

Limiter vs Clipper

So you might think that what I've described so far sounds awfully a lot like a clipper. If you did think that, you're not wrong!

The main difference is that a clipper abruptly shaves down any transients, and in the process gives you a more saturated sound. Limiters use a broader form of gain reduction that gets you a clearer and more transparent sound.

Both have their use cases in audio production and you just need to pick the tool that gives you the results you want.

Understanding Audio Signal Path

A typical signal path in your DAW should include EQ and compression before applying a limiter plugin.

Placing the limiter at the end of the signal chain is standard practice; it ensures that all previous processing like EQ adjustments and effects are taken into account before limiting is applied, allowing for a final volume adjustment without unintentional distortion. This allows you to fine-tune the final output.

How To Use Limiting in Music Production

Controlling Dynamics on Individual Tracks & Buses

I'm sure you've heard about limiters in mastering. But a limiter isn't just for the final master bus. It can also be used on individual tracks and buses to control peaks and ensure they don't interfere with the mix's balance. 

This helps you maintain clarity and consistent levels in your mix. 

By limiting peaks on individual tracks, you create space for other elements, allowing each part to be heard clearly. This contributes to a cleaner, more polished mix.

Applying a limiter to individual tracks, like vocals, kick drum, or other instruments, helps control unexpected peaks that might interfere with the mix. 

You can also use a limiter on buses; for instance, try inserting one on the drum bus after a compressor and it can work wonders for your drum mix.

Here's how to do it:

Threshold

Start by setting the threshold just below the loudest peak of the individual track. This could mean catching sharp transients in drums or smoothing out sudden vocal spikes. 

Aiming for -1 to -2 dB of gain reduction is usually enough to tame peaks while maintaining a natural sound. 

Too much reduction can lead to an unnatural, compressed sound, so avoid pushing it too far unless you’re looking for a specific effect.

Release Control

The release time determines how quickly the limiter stops applying gain reduction after the signal drops below the threshold.

For individual tracks, a faster release can often work well, especially with instruments that have short transients like drums. However, for elements like vocals or pads in electronic music, you might want a slower release to maintain smoothness. 

Many limiters offer adaptive release options, which adjust automatically to the incoming audio.

Output Ceiling

While you might not push the output on individual tracks as hard as on the master bus, you still want to set an appropriate ceiling to prevent clipping.

Mastering and the Master Bus

In the mastering process, a limiter is often placed on the master bus to control the overall loudness of your track. It acts as a safety net, ensuring the final mix does not exceed 0 dBFS, which is essential for preventing distortion.

Using a limiter in mastering can help meet industry loudness standards, and your goal is to maintain overall loudness while keeping the mix clean and free from distortion.

Don't fall victim to the loudness war! Louder in this case is not necessarily better. The master needs to sound full yet natural.

Threshold

Set the threshold just below the peaks of the loudest section of your mix. Aim for around -2 to -3 dB of gain reduction to prevent peaks without squashing the mix too much. 

Using a true peak limiter at this stage is critical for ensuring that no inter-sample peaks cause distortion when your track is played back on different systems or streaming platforms.

Release Control

On the master bus you’ll want to be more cautious with the release time. A slower release is generally preferable to maintain the overall dynamics of your track. Advanced limiters, such as those from Tokyo Dawn Records, offer intelligent release modes that adapt to the specific range of frequencies in your mix, allowing you to maximize loudness without sacrificing detail.

Output Ceiling

Set the output ceiling between -0.3 dB and -0.8 dB to prevent clipping, especially when exporting for streaming platforms. This will ensure your track stays within the platform’s loudness requirements while still sounding powerful.

Important Tips:

• Whether using limiters on individual tracks, group buses or the master bus, avoid going overboard with it, as too much dynamic range compression can result in a lifeless audio track.

• Use multi-band compressors before the limiter on more complex tracks if needed, allowing you to manage specific frequency bands independently.

• Check the amount of gain reduction and ensure you’re balancing loudness with the integrity of the source material. A little limiting can go a long way in giving your track that polished, professional feel.

Technical Insights: Settings and Usage

Best Practices for Gain Staging

Proper gain staging plays a crucial role in maintaining the integrity of your audio. It all starts from managing your input level; keep it within the acceptable range to avoid clipping while maximizing clarity.

Pay attention to the output levels from plugins like EQ and compressors within your signal path as well. Human ears perceive louder sounds as better, so it's important to maintain consistent levels in order to make the right decisions when mixing.

One important thought I'd like to share here - No amount of limiting can help fix issues caused by lack of proper gain staging.

Finding the Sweet Spot

Effective limiting begins with setting the threshold. Adjust the input gain to ensure your output signal remains clear yet powerful. Monitor this both by listening carefully, and visually using the limiter's meters to avoid unwanted distortion. 

Aim for a seamless sound by balancing the release time; too quick, and it might pump, while too slow can make your audio unresponsive.

Choosing the Right Limiter for Your Project

Evaluating Plugin Options

Popular DAWs often come with built-in limiters that can serve as a good starting point. There are also many specialized 3rd party plugins that give you a wider range of options with more advanced features.

Popular Limiters in the Market

Here are some I personally use a lot:

• The FabFilter Pro-L 2 is renowned as a great limiter for its customizable features and pristine signal clarity. It provides an intuitive interface for achieving precise control over your audio.

• The Waves L2 Ultramaximizer is another popular choice, known for enhancing loudness while maintaining clarity. 

• Other exceptional plugins include iZotope Ozone with its multi-band capabilities and Softube’s Weiss MM-1 for its extended features that cater to mastering demands.

Choose a limiter that best suits your project needs, keeping in mind compatibility with your existing audio gear and software, and the end sound you aim to achieve.

Using a Compressor As a Limiter

If your DAW doesn't come with a limiter, you can also use a compressor to achieve some of the same effect. You'll need a compressor with the ability to set high ratios.

In Soundtrap, you can use one of the built-in compressors, Compressor One or the Dynamics Compressor. The Dynamic Compressor is especially well suited for this because it has all the typical controls of a compressor, including threshold and attack.

Set the compressor's ratio all the way to 20:1, a fast attack and adjust the threshold to a level where you can hear the input signal starting to get limited. Find the sweet spot where the threshold begins to limit only occasional high peaks of the audio signal.

This effectively makes the compressor work as a brick wall limiter, though keep in mind that a compressor will still allow some signal still through the threshold and won't work quite as well for limiting purposes as a dedicated limiter.

Implications for Streaming and Distribution

When you're exporting your final master for a streaming platform like Spotify or Apple Music, be sure to check their requirements for loudness levels (LUFS). Make sure your audio files maintain a consistent maximum level.

When listeners access your content across various platforms, uniform audio quality is extremely important as it enhances the user experience. Aim for balance and clarity in your master to ensure it translates well across, whether it's a song or a podcast episode.

Conclusion

A limiter is an important tool that helps you set the proper volume level and dynamics for elements in your mix. It's also a vital final step in audio mastering that helps set the output level and perceived loudness of your master.

When using a limiter, remember to monitor your levels carefully both by listening and visually with meters to find the perfect balance. 

Trust your ears; if it sounds good, it is good. But also remember to check against reference tracks within the same genre so you know what your target sound should be.

Applying a limiter strategically in your mix or mastering chain can elevate your music while preserving its dynamic range.  When used thoughtfully, limiters are one of the best tools to achieve professional, polished sound for any project.

About the author

Tero Potila is a professional music composer and producer. His career combining knowledge and experience from music, TV, film, ad, and game industries gives him a unique perspective that he shares through posts on teropotila.com.