Item: FabFilter Pro-L 2
Rating: 4.8
Author: Noizefield

On December 5th FabFilter released Pro-L 2, a new release of FabFilter's Pro-L limiter plug-in. We had the chance to review the new limiter in our Noizefield test lab.

The Pro-L 2 is a professional true peak limiter plug-in for mixing and mastering. Fabfiter themselves describe the Pro-L 2 as a combination of all different limiting flavors and qualities in one plug-in, making it suitable for any type of music/audio. It can be as transparent as needed, and can go as loud as you want it to go. Equipped with excellent (loudness) metering, true peak limiting, surround support, oversampling and dithering, Pro-L 2 is everything you need in a limiter.

A modern, simple and intuitive GUI

A reason why FabFilter became more and more famous over the last years and why more and more people are using the FabFilter plug-ins is probably the extreme well designed and unique approach to the graphical user interface (GUI). Instead of displaying a virtual emulation of a real hardware, FabFilter has gone into a totally different direction and tried to be as functional and flexible as possible.

This concept does work extremely well and once you've worked with FabFilter stuff you will really miss the "feeling" of its great GUI on all the other more conventional plug-ins. The new Pro-L 2 even goes further and several improvements where done. The level meter got new display modes, including an Infinite mode that shows all audio for an entire session. Every time a more drastic change in the gain reduction is applied a special peak label is displayed to give additional insight in the limiting process. A super handy feature that is not seen in other limiter plug-ins until now. Another cool thing is the very flexible scaling of the GUI. There is even a full screen mode that displays the GUI on the whole screen.

New limiting algorithms

The four new limiting algorithms Modern, Aggressive, Bus and Safe are available in the new Pro-L 2 limiter. Together with the existing algorithms there are now 8 different options available. This makes the Pro-L 2 very flexible and gives the mixing engineer more options if it comes to a specific sound or genre. The Modern algorithms was designed for your daily "go-to" limiting and FabFilter mentioned that Modern produces better results than the Transparent and Allround algorithms from the old Pro-L. The next new algorithm with the name Aggressive was aimed to achieve maximum loudness suitable for EDM, Rock and other "loud" genres. Especially for drums and individual tracks the Bus algorithm was created. Last but not least the Safe algorithm was made to avoid distortion at all times.

True peak limiting and true peak metering

Another new feature of the Pro-L 2 is true peak limiting. True peak limiting can be enabled by a simple click on the corresponding button in the bottom menu bar. The true peak limiting avoids inter sample peaks that could be higher than the level of the real sample. If the true peak limiting option is enabled, the output values will be displayed as dBTP which stands for dB True Peak instead of dBFS (dB Full Scale). In general the true peak limiting feature does make a lot of sense and some would ask why this is not enabled in general for all limiters. The answer is that the detection of inter sample peaks does need a bit of time and adds extra latency to the process. Depending on the DAW the Pro-L 2 limiter will add about 5ms latency if true peak limiting is enabled. More about true peak limiting can be found here: www.broadcastbeat.com/

Also the metering of the Pro-L 2 is now capable to display inter sample peaks. With a simple kick on the TP button in the meter section the true peak metering can be turned on or off. For mastering purposes this feature is a great addition and helps to provide a perfect master ready for publishing. Also in the metering department are new options available as there is support for the EBU R128, ITU-R BS.1770-4 and ATSC A/85 standards.

Surround, Side Chain and other new features

FabFilter Pro-L 2 supports surround audio including Dolby Atmos 7.0.2 and 7.1.2 formats with flexible surround channel linking. The plug-in automatically detects the surround setup and adopts to the format. FabFilter added a 32x linear-phase oversampling mode for avoiding aliasing artifacts and distortion. This mode is quite CPU intensive and should be only enabled in the final mix down. A new DC offset filter removed all unwanted direct current and ultra low frequency content.

The Pro-L 2 does now also offer the possibility to use a side chain signal for the detection path of the limiting process. This can be very useful for stem mastering, when you need to deliver individual stems that have been processed with the exact same limiting as the original master. To achieve this, use Pro-L 2 on the stem channel, while feeding the original (unmastered, unlimited) master to its side chain input.

Last but not least a very helpful and mostly underrated feature is a unity gain option. in simple words unity gain ensures the exact same output level or reduces the output loudness to the same level of the input signal. The result is that you can listen to the limiter and the limited signal without and increase in loudness which makes the comparison between the unprocessed and the limited signal much more transparent and easy. We all know that a louder mix appears always to sound better. Finally there is an option to listen only to the difference signal or the "delta". This mode was made to present only the compression to the listener. Therefore a to drastic setting and over compression can be detected more easy.

All the core features of the Pro-L 2 in short:

Great transparent sound combined with maximum loudness
Eight sophisticated, carefully tuned limiting algorithms, all with their own character and purpose
True peak limiting
Up to 32x linear-phase oversampling to minimize aliasing and inter-sample peaks
Low CPU usage
Highly accurate output and gain reduction metering including true peak metering
Extensive loudness metering with support for the EBU R128, ITU-R BS.1770-4 and ATSC A/85 standards
Various meter scale settings, including K-System support
Surround support including Dolby Atmos 7.0.2 and 7.1.2 formats with flexible surround channel linking
Unique, highly informative real-time level display, showing input, output, gain change and loudness levels over time with key gain reduction readings and four different display modes
Optional DC offset filter
External side chain triggering for stem mastering
Unity Gain option to easily listen to the effect of the current limiting at unity gain level
Audition Limiting option to listen to the difference between the input and output signal
Adjustable Look-ahead, Attack and Release settings to fine-tune the sound of the algorithms
Separate, freely adjustable channel linking for both the transient and release stages
Professional dithering with three different noise shaping algorithms
Easy to set up for common limiting situations with the included factory presets
Adapts automatically to stereo, mono and surround channel layouts
Full Screen mode for precise adjustments and insightful metering
Multiple interface sizes: Small, Medium, and Large, as well as a separate Compact mode
Retina support on OS X and High DPI support on Windows
GPU-powered graphics acceleration
Supports common Pro Tools hardware control surfaces

Is the Pro-L 2 the answer to all limiting tasks?

From the feature set the new Pro-L 2 is hitting the "brickwall" and set's a new benchmark. FabFilter did a really great job and added so much incredible stuff to the Pro-L 2. But how is the sound? In simple words the sound of the Pro-L 2 can be everything: Brutal, gentle, aggressive and invisible and that is exactly what most people want from a limiter.

In comparison with other limiters the new Aggressive mode does sound more full and has a bit more pressure. In comparison with a mastering badass multiband limiter the Pro-L 2 will lose if it comes to pure loudness but the plug-in will win if it comes to sound and artifacts.

The only thing on my wish-list would be a multi-band version including a mid/side option for each band, but most probably this is a task for the FabFilter Pro-MB...
All in all the Pro-L 2 is one of the most advanced and professional limiter plug-ins on the market.

FabFilter Pro-L 2 is directly available for EUR 169 / USD 199$ / GBP 149£ at the FabFilter website here: FabFilter