Recording Magazin 02/2014
Chris Lausmann: "In a market dominated by a few high end passive EQs by Manley and Pultec there are only very few good EQs with a reasonable price tag, and this is exactly what the xfilter stands for, making it a a truly reasonable acquisition for any professional studio."
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SafeAndSound 02/2014
Barry Gardner: "I am very happy to have this new equaliser in the rack, it is very capable, very flexible and is firmly a unit living in the high end category. It adds further tonal options and complements my existing custom equaliser and the Manley Massive Passive."
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Ask Audio 01/2014
Mo Volans: "If you are considering getting an analog EQ for this purpose you really couldn't go wrong with the xfilter. It’s cost effective as far as analog EQs go and it will do just about everything you’ll need it to and a touch more. This really is an awesome bit of kit…”
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Amazona 12/2013
Markus Schröder: "The xfilter is a very flexible and musical, yet controllable and transparent equalizer for every day studio use. elysia has managed to extend the usual sweet spots onto the full range of all its parameters without degrading the original clearness of the signal at all."
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elysia xfilter rack version

by Francis Kimberly
Audio Slap (UK) – December 2013

Earlier in the year elysia released the xfilter 500 series EQ. For not very much money it included a wealth of functionality and it appeared to plug a gap in the market for a true stereo EQ in the 500 format. Reviews came with high praise, not just for the concept but for the execution and sound, so when they released a rackmount version I had to have a look…

What is it?

The xfilter is a stereo EQ in 19″ rack format. It can also be used in mono, but not dual mono. It boasts 2 Mid Peak filters which both have a switchable Q position in either “Wide” or “Narrow”. There are Low Shelf and High Shelf bands which can be switched into Low and High Cut filters with adjustable Resonance. There’s also a rather cool feature called the Passive Massage – more on this later. I/O are taken care of with XLR  and 1/4″ options, and you also have an extra pair of outputs courtesy of 1/4″ connectors. Although I didn’t get chance to test these out I have been assured by elysia that they can be used as alternative outputs, essentially splitting the signal, to route elsewhere and increase your options. Power supply is contained within the case so you only need to connect a standard IEC lead. The power is easily switchable between 230V and 115V depending on where in the world you are. It also comes with 2 years manufacturer’s warranty.

First Impressions

When I unpacked the xfilter what first struck me was how good looking it is. The main casing is a plain ol’ metal grey that sparkles pleasingly in the light but it’s the front panel that gets me hot under the collar, combining a very straight forward layout with an alluring colour scheme. The grey/silver pots and white legending clearly stand out on a background of night sky blue. The curving, angled edges in the centre of the unit gently give an impression of shape and draw your eyes to the smouldering white of the elysia logo in the middle. The reds and orange of the LEDs mean you can always quickly reference what’s been switched while never looking garish. Some people may find it looks a bit functional, but you can probably tell I very much like the way it looks! It does what it needs to while quietly stealing the show in your rack. Big thumbs up.

In use

The unit, while light, is rugged in construction and obviously has been built with longevity in mind. The pots are reassuringly sturdy and give a nice amount of resistance when turned while the button switches in the middle of the front panel are smooth in action and never feel “empty” or cheap. Each pot has 41 steps which are easily distinguishable by touch. Despite being detented controls, sweeping around the frequencies always gave a smooth sound with no obvious “stepped artefacts” here. The pots and buttons are nicely spaced out enabling those of us afflicted with Sausage Fingers to operate the unit without making unintended changes to other controls or having to resort to a pair of tweezers and a cocktail stick. However, the legending around the pots is cramped and I found this negatively affects the interaction you can have with unit and the ease of recalling settings at a later date. For instance, each pot has the usual +/- numerical values around them but the “Gain” and “Freq” text is crammed into the same space and some of the numerical values have been removed to make way. While this is hardly a dealbreaker there is a section of each pot’s turn where you’re left thinking, “…and what exactly is the value here?”. Also, and doubtless because of the glorious 41 steps on offer, there simply isn’t enough space to label each individual step and its associated value. While your mileage may vary with each of these points if you’re in a situation where exact noting and recall of each control value is critical this may put a dampener on proceedings and make the process slightly longwinded.

The flexibility of the xfilter is very impressive. At a switch of a switch you can… erm… switch between Low and High shelves and Low and High Cut filters. When engaged as shelves the associated Gain controls act as just that and allow for +/- 16dB. When engaged at cuts the Gain controls act as Resonance controls. The simple button-press operation to go between the two features belies the monster of a sound shaper that this turns the xfilter into. In addition to these filters you also have the two Mid Peak filters which, between them, cover all the way from 45Hz right up to 16kHz.  They come in two flavours each – Narrow Q and Wide Q – and according to the graphs in the manual they offer +/- 12dB in Wide and +/- 14dB in Narrow. Slightly confusingly, but also making sense once you realise elysia have had to split the difference, the Gain pots are labelled as +/- 13dB on the front panel. On top of all this you have a rather clever function that elysia have called the Passive Massage. Easily switchable from the front panel, this fixed LC filter dishes up a slight peak at 12kHz and then a roll off from 17kHz (I’m not going to pretend to know exactly what an LC filter is, or how it works, but the provided graph shows what appears to a low pass filter with a bump just before the fall). The magic trick here is that this is passive circuitry and affects your audio with all the luvverlyness that passive circuitry can afford. With all the shape shifting power on offer over the four main bands it’s frustrating that there’s only a global bypass option available and not per-band bypass options. In order to A/B individual bands you have to turn the appropriate Gain knob as quickly as possible to 0dB while making a mental note of what you had and then going back up to the step you had it on. With no easy reference for the steps, and with 41 to choose from, it can get messy and more-or-less destroy any attempts at A/B comparisons. This frustration doubles with the Low or High Cut filters when you have two pots to fiddle with.

The Sound

So far I’ve purposely avoided talking about the sound as it would’ve held up the rest of the details because, quite frankly, I could wax lyrical for a long time about how it sounds. elysia claim the xfilter is “exceptionally transparent” and I have to agree with them. Switching between “Bypass” and all controls set at neutral showed no audible difference between the two paths. Engaging the Low Cut and High Cut for a bit of top'n'tailing on a full mix did just that and nothing more, removing the intended frequencies cleanly and effectively without imparting any unwanted character to the audio. Same with the low and high shelves. Moderate dipping and rising with the Mid Peaks showed that it was focused with no smearing or lack of detail. However, when used gently the Mid Peaks can be quite reserved, so much so that it was sometimes hard to tell if the Mid Peaks were working when being used with low Gain values, and this reviewer also couldn’t tell much difference when switching between the Narrow and Wide Q settings at slightly higher Gain values. So far so clean and transparent, but once pushed beyond the equivalent of an easy stroll then the quality of the unit really shines. Settings that you might normally consider extreme are easily taken in its stride with no distortion or strain. Ocean trench sized cuts are impressively tidy while astronomical boosts are kept firmly under control resulting in some wonderfully full and warm sounds.

The Resonance controls for the Low and High Cut filters don’t seem to do much before passing 12 o’clock on the pots, but once pushed a little bit kicks and basses start biting nicely and the high cut plus Resonance has a nice habit of making high frequencies sound more “expensive” than they did pre-processing! Speaking of expensive sounding high frequencies, I loved the Passive Massage switch. On the right material this switch alone is almost worth the asking price of the unit. While reviewing the xfilter I mastered some acoustic rock that had been, for artistic reasons, recorded on a 4 track cassette recorder. While it had been expertly produced some tracks lacked a certain depth in the high end, perhaps due to the recording medium. With all controls on the xfilter at neutral I engaged the Passive Massage and – bang! – the material came alive! Previously buried details uncovered themselves, reverb tails shimmered, vocals and guitars glistened… You get the idea, I’m sure! I used the Passive Massage on some house music too with the same results (albeit with different instruments). Individual instruments can also benefit hugely. As previously mentioned, it doesn’t suit everything you can give it but it’s an awesome shortcut to making your music sound fantastically expensive. If elysia were to make a small unit that only contained the Passive Massage switch and circuitry I would be first in the queue!


I had a great time with the xfilter. elysia are proud of the care and attention to detail that goes into the component selection and construction and this really comes through in the unit. With a street price of £899 +VAT, to get such a high level of workmanship and quality of sound for so little is a big achievement. Indeed, I can only think of a few stereo EQs with comparable quality anywhere near this price and none of them have the amount of features that the xfilter offers. Due to its range of potential applications the xfilter could easily find a home in either project or professional studios and would also make perfect sense for a lone producer or instrumentalist wanting a high quality EQ to bolster their sound. While there are certain operational quirks that could be improved upon I imagine they would push the price up considerably. This is a highly flexible, top quality, modern EQ with a very attractive price. Highly recommended.