SPL Qure

Stereo 3 band parametric EQ

SPL Qure Stereo 3 band parametric EQ

Review by George Shilling

It never ceases to amaze me that many items are sent for review that are either faulty, or fail to include the (often vital) manual. If it happens to me, it could certainly happen to you. Whilst neither of these problems afflicted the SPL Qure, the supplied manual was in German, perhaps forgivable because this is a new model. Unforgivable was that two calls to the distributor failed to elicit one, despite promises, and even the manual on SPL's otherwise excellent website refused to download. It was eventually emailed, accompanied, of course, by an apologetic telephone call from Germany…

Essentially, the Qure is a dual-channel parametric EQ. Housed in a smart 2U box, each channel features full 3-band parametric EQ, High- and Low-Pass filters, Input and Output gain knobs, and the magic 'Qure' controls, more of which later. Rear panel layout is good, with both XLRs and jack connectors, and additional upside-down legending for instances when you are peering over the top. A ground-lift button and a voltage selector are adjacent to the IEC Mains-socket.

The two channels are arranged side-by-side, but panel space is wasted with large grilles showing off two glowing Sovtek 12AX7 valves. Very nice, but the space could have been used to improve the layout. At switch-on an unnecessary Warm Up LED glows until the Ready LED kicks in after a minute or so, this slow voltage build-up claiming to lengthen valve life. On both channels, each of the three EQ bands has an 'On' switch and there is a combined 'On' switch for the two filters. These are cute white buttons, which miraculously light-up red when switched in. They all momentarily mute the signal as you press them, apart from one on the review model which I assume was faulty: the MF button on Channel 2 produced a deafening howl when half-pressed. Ouch. The red switch at the far right labelled 'Master' is an overall bypass, activating both channels simultaneously with a satisfying relay click. With Master 'in' and all other buttons 'out' there is a noticeable 'warming' of the sound, as valve circuitry is now operative, as are the gain knobs. However, with gains at zero there is a small level boost, which will undoubtedly enhance your signal!

SPL Qure Stereo 3 band parametric EQ

Confronted with a sea of twenty-eight identical black knobs, the layout is initially slightly confusing. These very smart knobs unfortunately have no pointers along their rather deep sides, therefore accurately lining-up with the legending is slightly tricky, despite helpful détentes at various spacings, intended to make recalling settings easier. The frequency knobs each have 31 détentes, which slightly impedes smooth sweeping, whereas the Output Gain has only a centre détente, making accurate recall difficult. On each channel, Input Gain (-12 to +18dB) is at top left, with Output Gain (-7 to +4dB) at bottom right.

The middle three columns of knobs on each channel are the parametric controls, with Frequency at the top, Bandwidth in the middle and Boost/Cut at the bottom. Frequency ranges are marked as 15-365Hz, 0.2-5.0kHz and 1.0-21kHz. Bandwidths (BWs) are marked 0.5 to 5, and Boost/Cuts (B/Cs) are marked +/-15dB, except for the Mid band, which has the same +15dB boost, but up to -36dB cut. LF Cut is 40-200Hz, HF Cut extends downwards: 20-2.5kHz. These are both 2nd order Butterworth filters. The EQ uses 'Proportional Q', where the amplitude of the processed frequency band is reduced as the bandwidth broadens. This means that a maximum 15dB boost can actually be between 12 and 16dB at the centre frequency, and the quoted 36dB midrange cut can be as little as 22dB with the broadest bandwidth. Different technologies (valve, transistor, etc.) are used for each band. This can lead to 'worst of all worlds' degradation, particularly with regard to phase accuracy. However, whilst not as 'open' sounding as some high-end competitors, the EQ works well, with a precise, musical feel.

The Qure control is marked from Min/0 to Max/20 and accompanied by 'Qure On' and 'Shift Qure' buttons. Switching on the 'Qure' section introduces a coil/condenser/resistor filter network into the tube output stage. Adjusting the Qure knob changes the frequency response and apparently alters 'phase response'. Without an oscilloscope it is impossible to assess technically what is occurring. The manual claims a 'sonic blur' reduces digital 'harshness', particularly on vocals. New harmonics are generated, and existing ones intensified. In practice, the Qure effect is fairly subtle, with Maximum sounding much like the application of several dBs of Mid/Hi boost (or mid boost in 'Shift Qure' mode). It also perceptibly reduces 'wooliness', and when processing a mix enhances vocal clarity. Switching in the process makes the signal louder by several dBs.

The long-awaited manual was good, if a little boastful and lacking humour, despite translation help from Paul White. When it comes to ergonomics, style has edged out functionality by a small margin. That's a shame, because audio performance is excellent, with quoted frequency response 10Hz to 100kHz and good S/N ratio. The Qure effect is rarely offensive, and less irritating than some enhancers. The EQ is definitely no afterthought, and this unusual unit is a 'must-try'.

Reproduced with kind permission from Copyright ©

Visit George's website to find more great reviews.