Recommended workflow

To get the best results with FabFilter Pro-L 2, we recommend the following steps:

Step 1: Choose a good starting point preset

Of course, the simplest way to start working with Pro-L 2, is to just open it with its Default Setting preset and move the Gain slider up until you reach the desired level. We have chosen the default preset carefully, to work well on almost any audio.

Instead of just using the default settings however, you can also try one of the excellent factory presets that come with FabFilter Pro-L 2. They are divided per musical genre and have descriptive names, so you can easily choose the preset that works best for your purpose and audio material.

To make it easy to try and compare different presets on your audio, while leaving the current amount of limiting, the specified output level and other output settings unaffected, make sure the Lock Output button is enabled. It's placed directly right to the preset controls, at the top of the interface. When enabled, the current values of the Gain, Output Level, DC Offset Filtering, Unity Gain, True Peak Limiting, Oversampling, Dithering and Noise Shaping parameters will be preserved while loading presets.

After a while, you'll probably have a favorite preset and favorite settings that you use most of the time. In that case, it's a good idea to override the Default Preset so that the next time you open FabFilter Pro-L 2, you're ready to go right away. To save all current settings as default, simply choose Options > Save As Default from the preset menu.

Step 2: Refine settings if needed

If you like to, you can of course adjust or refine the settings that influence the sound and flavour of limiting. Just open up the Advanced panel to get access to settings like Style, Lookahead, Attack, Release and Channel Link. To learn how to interpret these settings and adjust them with sense, see Advanced settings.

Step 3: Set up True Peak Limiting, Oversampling, Dithering and Output level with care

The final step in setting up the limiter is choosing the correct output settings. Whether you use dithering and noise shaping depends on your preferences and requirements. See Dithering and noise shaping for more information.

"So what's an appropriate Output Level setting? Should I choose -0.1 dB, -0.3 dB or -1.0 dB?"

Actually, there is not a single correct value for the Output Level parameter. It mainly depends on the presence and strength of true peaks (or inter-sample peaks) in the outgoing audio signal. Different metering and loudness standards allow for different maximum peak (i.e. true peak) levels.

In short, our advice is simple. Turn on True Peak Limiting and True Peak Metering (also known as inter-sample peak metering), which exposes true peaks in the processed signal. Then set the Output Level to the maximum allowed value (e.g. -1.0 dBTP for EBU R128).

In any case, make sure that the true peak output level never exceeds 0.0 dBTP. This makes it very likely that a subsequent D/A conversion (or any other conversion, like to MP3 etc.) will handle your audio without introducing distortion.

Notes

• Not everyone cares about true peaks or inter-sample clipping: see Output options for the full discussion.
• Inter-sample peaks are introduced when the limiter needs to react very quickly to the incoming signal. By increasing the Lookahead setting, you allow the limiter more time to respond, and therefore reduce distortion and inter-sample peaks.
• Another way to reduce inter-sample peaks and true peak overshoot is by using oversampling. In most cases, choosing 4x oversampling in combination with a minimum lookahead time of 0.1 ms, keeps inter-sample peaks within the range of 0.1 dB.
• The best way to ensure a maximum true peak level, is by enabling True Peak Limiting. This will smooth out the true peak overshoot after processing, ensuring the output never exceeds the current Output Level.
• Of course, Pro-L 2's True Peak metering fully complies to the EBU R128 / ITU-R 1770 metering standards.

Next: Advanced settings

See Also
Overview
Knobs and gain slider