Elysia - Xfilter
by Chris Lausmann
Recording Magazin (Germany) – February 2014
After releasing the xfilter 500 at the beginning of 2013, the renowned outboard manufacturer elysia now lets the rack version follow to complement its range with a stereo filter.
Being the little brother of the big museq, the xfilter is said to be more affordable but not much behind in terms of performance. The focus of the concept is a modern, clean four band EQ that has both active and passive topologies based on a class-A circuitry. The xfilter sits in a rugged housing which looks very nice with its aluminum front panel colored in the elysia-typical blue tone. The front shows eight stepped potentiometers with aluminum knobs which are accompanied by six push buttons with individual status LEDs. The back panel features extensive connecting options: Both inputs and outputs are available on symmetrical XLR and jack connectors. Plus, there are two additional external jack outs which offer the output signals in parallel.
The stereo concept means that there is a single set of controls for both channels. The components used for the filter stages are being selected in order to reduce possible component tolerances, which is especially important as the potentiometers used in stereo link use several layers: The frequency pots have a total of four layers while the gain pots have two. elysia solves this problem by employing computer routines especially written for this purpose. The quality aspect shines through with the special foil capacitors, too. Compared to its big brother, the museq, the obviously more affordable price results – among other factors – from the fact that the components are placed on the PCBs by robots (SMD) instead of doing so by hand. Also, the input and output stages are electronic designs which can do without expensive transformers.
Unlike the 500 series version on which the bands are laid out crossed, the rack version shows the typical arrangement from left to right. The left side begins with the gain and frequency controllers for the low shelf band, which can be switched into a high cut filter with resonance. With it, you can for example push a kick drum at 60Hz while cleaning up low frequency rumble at the same time. The high shelf band on the right side offers the same feature, too. The shelving filters sound very smooth with a full bass and airy treble, and they can be controlled very exactly. Once the bands are switched into their cut modes, the filters work with a slope of 12dB per octave.
The remaining four controllers represent the high and low mid bands, which also offer an individual gain and frequency controller each. The Q of these bands can be switched from a wide mode into a narrow mode. But even the narrow mode is still quite wide and smooth, meaning that it is not really well suited for notching out unwanted frequencies – it's much more about shaping the sound.
A highlight of the xfilter is the “Passive Massage“ button. This function is an additional passive high band that can be used to get more “air“ onto the sound. This fixed filter has a slight resonance peak at 12kHz and starts to gently fall off at around 17kHz. This way only the frequency area around the peak is accentuated without boosting the complete HF spectrum. Once engaged, you directly notice how your signals open towards the high frequencies. One could say it's a “good becomes better“ switch.
I inserted this EQ before my bus compressor and used it on a drum bus. I was amazed by how precise you can set your curves with the stepped potentiometers. In terms of sound, the EQ even does not hurt when its pushed really hard.
I also found the shelving filters with resonance very interesting. The drums gain in punch and get cleaned up at the same time. You need to play a little bit with the filter frequency to find your personal taste. In order to open up the overheads, I first used the high shelf filter, but I ended up with the high cut with a resonance peak around 10kHz. It just gave me a better overall grip on the upper frequencies, and as a result, the complete drum set sounded much more tight and monolithic.
During an unplugged production I faced the problem that the doubled guitars sounded slightly dull. The xfilter surprised me with an amazing result in this case, too. For the low frequencies, I used the low cut filter again, which gave me a certain warmth around 100 and 200 Hz, but at the same time in generated enough space for the kick and the bass in the mix. The upper mids originally came with an unpleasant ringing sound which could be nicely discarded with the upper mid band in narrow mode. Attack and airiness could be improved with the high cut filter. Finally I also hit the “Passive Massage“ button, with the effect of a slight saturation that almost reminded me of certain tube circuits. As a result, the guitars sounded more 'expensive' and got a prominent place in the mix. I got similar benefits when using the EQ on lead vocals – the xfilter is also of big benefit when used as a mono equalizer (with one of its channels idle).
The complete picture shows an EQ that does a very good job. 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. Especially in combination with the other elysia processors, the xfilter is a truly reasonable acquisition for any professional studio.