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Flux Epure

Flux Epure v3

4.5 4.5 out of 5, based on 1 Review

A classy equalizer plugin from Flux that stood the tests of time.

11th July 2014

Flux Epure v3 by Diogo C

Flux Epure

  • Plugin: Epure Equalizer
  • Developer: Flux
  • Formats: AAX, VST, AU. Mac/Win, 32/64.
  • Price: 139 euro MSRP
  • DRM: Ilok2
  • Website:


Getting a good sounding equalizer is definitively not a hard thing to do in today’s hyper-crowded DAW plugin market. However, choosing one can easily become a problem given the myriad of superb options that are out there, and its not hard to get lost in endless testing until the end of our lives. Just look at our New Product Alert section and you’ll quickly realize that new equalizer offerings are made all the time and threads like “is that EQ better than that EQ?” are omnipresent all across this board. Therefore, some focus is strongly advised when hunting for those perfect curves to shape your sounds.

For the purposes of this reviewer, it usually boils down to two fundamental aspects: sound quality and workflow - the later being a sum of stability, resource consumption and ease of use. I’d add a third criteria for cost, but luckily for us there’s something for every pocket as the competition immensely escalated in the last 10 years, but its definitely something one takes into account - especially when they already have a bunch of options in their plugin folders. Each of those aspects have different weights for each one of us - that goes without saying - but I strongly feel like this is a good criteria for putting an extremely common and abundant tool such as an equalizer into some perspective. In the light of that, today we take a look at a plugin that’s been around for almost ten years, yet still gets a lot of praise from our peers: the Epure Equalizer, made by the Frenchmen at Flux since 2006.

Sound quality

Flux offers us a minimum-phase equalizer, wired in-series and pretty much without any bells and whistles. It offers five overlapping bands that can be set to work as a parametric bell, a shelf or a HP/LP filter. The bells are capable of very precise and very broad equalization, with a wide range of bandwidth of options. The shelves and the 12 db/octave high/low cut filters are extremely smooth and are great for a good range of mixing and mastering situations, but since they have fixed Qs they are not as flexible as some might want. Nonetheless, what these shelves and filters lack in flexibility they really make up in terms of sound quality - and that's easily perceived when you start to realize that with Epure you actually can go a bit further than usual as it sounds so natural, and this plugin is far more forgiving than most equalizers out there. Flux made an EQ that really needs to be pushed to be felt present. Overall this is a phenomenally natural, clean and transparent plugin - I know these are very vague words, but there is no other way to describe what it does in different terms. It can handle a decent amount of abuse without sounding “phasey” and its one of the most “stealthy” sounding processors in this category. I can’t really think of a better term to describe it than “stealthy”, but of course that doesn't really apply to that 10 dbs boost you just did at 100 Hz, but If you’re doing small increments you’ll eventually bypass it and turn it back again to make sure its really working, and you’ll realize it is working and most of all, how good it is working.

Released back in 2006, Epure has aged extremely well and has managed to keep its relevancy. This is due to the fact that it is such an elegant piece of work, combining superb sounding curves and an interface that really stood the tests of time. Epure hasn’t changed much since its release and its “sound engine” is still the same, but it hasn’t really lost any of its charm (and value) since Flux is constantly keeping up with the latest plugin formats and the core of the design is just very good to begin with. It’s a solid foundation and one that gives Epure the chance to stay relevant in 2014.

In use

Epure is incredibly simple and straightforward to use. Grab the knobs or the graph handles and tweak to taste. Epure's boosts and cuts are symmetrical, its quite easy to get familiar with how this plugin operates. Epure is essentially a “proportional Q” design if you don’t touch its bandwidth controls, and its curves are very broad up until 12 db (boost or cut) when they start to get sharper. Given the fact the the bandwidth control’s range is pretty large, Epure can do both heavy lifting and precise interventions extremely well. Flux has certainly paid attention to their Gain/Q relationships and came up with a very precise yet gentle-sounding equalizer.

The clean and unobstructed interface has pretty much everything you need in right in your face, and there aren't many things under the hood here. The “hidden” settings have no effect in its sound quality, so you don't have to worry with any optimal configurations as Epure comes ready to serve. There's a menu for the routing matrix and the global Flux menu where the user can set the number of inputs, enable or disable latency report and multithread options, a handy button for the PDF manual and that's it, nothing more. Right-clicking on the graph brings up some convenient options such as variable scales from -6 to -24 dbs and copy/paste from each group. These groups are how Epure handles the input channels, and it can handle up to eight channels in L-R, M-S or surround. The routing matrix for these groups is a breeze to use and allows the user to easily assign their desired multichannel or mid-side routing quite easily.

The preset system is also neatly organized and can host A/B settings. A great feature that Epure shares with other Flux plugins is the A to B slider, which morphs setting A into setting B. This is quite a powerful tool and can be used in creative ways. Another sweet feature here are the x2 and /2 options for the amplitude of each band, and its also possible to invert each of the bands amplitude. Last cool thing to mention is the frequency resolution offered here: the low frequency offers two settings (5 and 20 Hz) and high frequency range extends according to the sample rate set by the project, going all the way to the supersonics - something which not all equalizers out there can do for some reason. Some might argue that the amplitude resolution might not be enough at -24 dbs but if you have to use more than twenty-effing-fours dbs of equalization…well, let’s just leave it that way, alright?

Graphically this is a very elegant and well organized tool, but some might argue that there's major flaw in terms of features since Epure doesn't have any metering or spectrum analyzing tools. Epure has none of that. Not a single meter at all. Equalizers historically don't have metering, but in 2014 that's something hard to accept from a over a hundred bucks plugin.

Performance and support

Epure is very light on the CPU and basically any modern computer can run dozens and dozens of instances without draining too much resources. Given its spectacular sound, this quite an achievement that Flux can be proud of. All around this is a very stable plugin on all tested platforms, however, some minor quirks showed up on the VST and AU versions and some troubleshooting was required, and this is where I feel like Flux failed lived up to its sonic standards. Their ticket-based support system seems faulty as messages will go unanswered and I had to resort to a more direct approach to solve the problems I was facing. Fortunately, I could reach of their guys here at Gearslutz and we hunted down the bugs and eventually we succeeded.

The documentation also feels a bit shallow and won’t go beyond the basic operations. A mere five-page long user’s manual is all we get, and I strongly feel like Flux could have gone to greater lengths here and talked about what goes on under the hoods of their design, or at least gave the user some basic orientation on the fundamental of equalization. My personal benchmark for EQ manuals has been for a long time the Waves Renaissance Equalizer, as it manages to bring together operational guidance, technical data and cool insights on the bigger picture of equalizer design. All in all, these flaws have little weight on the overall perception of this plugin and don’t really hurt its sonic excellence.


Flux has created an equalizer that is arguably in the top-five greatest digital equalizers ever made and I could easily understand if someone told me that Epure is their favorite, because it is really that beautiful sounding and easy to the point it feels very elegant. It also has a great workflow, runs on basically any platform and it runs light so you can run many! If you’re still looking for an equalizer that does basically any job and doesn't get in your way with too many technicalities, Epure might just make you stop looking. Even though it seems less-featured than some of the competition, it greatly compensates that with sheer sound quality and ease of use.

  • Sound Quality: 10/10
  • Ease of use: 10/10
  • Features: 8/10
  • Compatibility and stability: 8/10
  • Documentation and support: 8/10
  • Bang for buck: 9/10

Just for curiosity’s sake, here are some plots from Epure in case you’re wondering how its curves looks like:

2k parametric bell, +18/-18 dbs, default Q (7.00)

Flux Epure-2k-bell.jpg

100 Hz Low Shelf and 5 kHz High Shelf (+1 db increments)

Flux Epure-shelves-100-5000.jpg

HPF 20-100 Hz (10 Hz increments) and LPF @ 20-10 kHz (1 kHz increments)

Flux Epure-lp-hp.png

Some alternatives:
  • Sonnox EQ: The “classic digital” equalizer designed by Sony-Oxford back in the 80s for their digital consoles. Still a great sounding piece and also easy to use, but one that comes with a steeper cost.
  • DMG Audio EQuality/EQuick/EQuilibrium: The DMG triad are a serious contenders and arguably Epure’s major rival. It will come down to personal taste here, as cost and sound are very close, especially when it comes to EQuality and EQuick. EQuilibrium is arguably the “better” equalizer because of its endless feature set, but more costly as one might suspect.
  • Waves Renaissance EQ: Another one that stood the test of time because of its brilliant design. RenEQ has more curve options, but I’ll dare to say that Epure is better sounding and its definitely easier to work with. Even if you don’t get the plugin in one of those crazy Waves deals, try to get your hands on the PDF manual!
  • Fabfilter ProQ: Also a serious contender for the crown of the most cost-effective equalizer. Very well featured, reasonably priced and of course, great sounding and relatively easy to use.
  • DDMF LP10/IIEQPro: Inexpensive and good sounding. The interfaces are a bit clunky, but no game-breakers. Given the price, you can’t really go wrong with them.
  • SSL Duende X-EQ: Not mentioned very often because of its hardware needs and dongle conundrums, which are now gone. Featured-packed and great sounding, the SSL X-EQ can’t be overlooked.
  • Algorithmix PEQ Blue: From a bygone era of expensive digital plugins. I’m putting this one here since some people swear by them and they were immensely praised some years ago, but that praise is certainly fading in the present because of its insanely high cost and lack of updates, making its use restricted in today’s DAWs.

Attached Thumbnails
Flux Epure-imgext.png  

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