FabFilter Pro-Q (Mac/Win) Review

In a crowded field of equalization plug-ins, FabFilter Pro-Q ($199) stands out by providing sky-high sound quality and an ocean-deep feature set.
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FabFilter Pro-Q offers mono, dual-mono, stereo, and mid-side equalization in an uncluttered GUI.

In a crowded field of equalization plug-ins, FabFilter Pro-Q ($199) stands out by providing sky-high sound quality and an ocean-deep feature set. Mono, left-right (dual-mono or stereo), and mid-side (M-S) modes of operation are just the start. The plug-in uses analog modeling for its splurging 24 EQ bands, each of which can be assigned to either the left or right channel in left-right mode, or to the mid or side channel in M-S mode (or to both channels at once in either mode). Display ranges of 6dB/12dB/30dB accommodate both mixing and mastering duties. Four modes of linear-phase equalization provide a banquet of alternatives to zero-latency processing.

Pro-Q''s 64-bit internal processing boasts virtually unlimited headroom. The cross-platform plug-in comes in AU, RTAS, VST, and VST3 formats. I tested the AU plug-in on MOTU''s Digital Performer 6.02 using an 8-core 2.8GHz Mac Pro running Mac OS X 10.5.4.

Pro-Q''s filters come in five different flavors: bell, low/highpass, and low/high-shelf. When you click on a band''s node in Pro-Q''s equalization-curve display, the band''s frequency, gain, Q, and bypass controls appear below the graph. These controls accompany facilities for choosing channel assignment (left, right, stereo, mid, side, or mid and side) and filter type, and deleting the band. Controls are shown for only one selected band at a time, but you can also mouse-drag nodes around on the displayed EQ curve to adjust parameter values.

At the top of the GUI are buttons for multiple undo/redo functions, A and B workspaces, preset management, and online documentation. Controls along the bottom choose the channel mode (left-right or M-S), adjust output gain, pan (in left-right mode), processing bypass, real-time spectrum analyzer on/off, MIDI Learn assignment enabling for EQ parameters, and selection of zero-latency and four linear-phase operational modes.

Dual-mono setup is hastened by a button that creates separate instances of the currently selected band in each channel for further independent tweaking. Dual-mono and M-S modes each display a differently colored equalization curve for each channel.

Each linear-phase mode imposes a different amount of latency, which is proportional to the degree of low-frequency resolution achieved. But choosing the mode with the highest latency (the most accurate mode) can cause a phenomenon called pre-echoes—very subtle advance ringing—when EQ''ing bass frequencies with high Q values on percussive content. Pro-Q''s various linear-phase modes let you fine-tune the degree of filter accuracy for use on different material.

Pro-Q is one of the best-sounding EQ plug-ins I''ve heard to date, especially when used on acoustic instruments. The sound is pristine and precise yet decidedly analog-like in its sweetness and dimension. The wide-ranging Q controls let me fashion classic overshoot responses, notch filters, and smooth tonal shaping alike. And its powerful dual-mono and M-S modes of operation place Pro-Q in an elite class of plug-ins that''s particularly valuable in mastering circles. Also, its hit on CPU resources is surprisingly light.

While many users will appreciate Pro-Q''s uncluttered GUI, I found it a hindrance that I couldn''t view the frequency, gain, and Q values for all bands simultaneously. You have to hover your mouse over each control in turn to see its numerical readout. Alternatively, you can position your mouse over an EQ node to see all three parameter values at once.

Filters applied to the mid (side) channel in M-S mode are arbitrarily applied to the left (right) channel when switching to left-right mode, almost always causing unintended results. The output pan control for left-right mode also retains its setting when switching to M-S mode, where it serves to adjust the balance between mid and side channels—again rendering unintended results. Ideally, all of these controls should have independent settings for each mode. A workaround is to dedicate, for example, workspace A for making adjustments in left-right mode and workspace B for mid-side mode, switching modes by alternately recalling workspaces.

I also wish Pro-Q''s GUI included I/O meters for mastering purposes. When applying EQ to only one side of a stereo mix, it''s important to see how the result affects L/R balance. But despite my complaints about its interface, I still give Pro-Q a 4 rating because of its superb sound quality and all-bases-covered feature set, and the price tag is reasonable. Better yet, you can bundle Pro-Q with the excellent FabFilter Pro-C (reviewed in the May 2010 EM) for $309. You''ll be glad you did.

Overall rating (1 through 5): 4
Pro-Q Product Page