PSP's latest equaliser seeks to combine analogue smoothness with digital precision.
It always seems to me that passive EQs have unmatched smoothness and finesse, while a good active parametric design has finely controllable adjustment, but few designs have both. PSP may have brought that ideal one step closer with their NobleQ and NobleQex. Clearly inspired by hardware passive equalisers such as the Pultec EQ1PA, the PSP NobleQ isn't an exact copy of anything specific, providing the expected features of passive equalisers but adding a wider range of frequency adjustment, an adjustable high‑pass filter, and the option to switch the high peak and shelf filters to either boost or attenuate. The audio sample rate is doubled within the plug‑in to create a smoother, more accurate response, and there's also a simulated tube make‑up gain amplifier with a user‑controllable amount of saturation that works so well it could have been sold as a plug‑in in its own right. As with most PSP plug‑ins, both Windows and Mac OS are supported, as are the VST, AU and RTAS plug‑in formats.
To take the basic NobleQ first, the secret to its big‑sounding low end is the provision of two low shelving sections: one boosts, while the other attenuates, but at a slightly higher frequency. A Low Shelf Freq pointer knob selects the cutoff frequency for both (although the manual reveals that the actual frequency is slightly higher than indicated). The Boost and Attenuation knobs can then be used together, and interact in a similar way to those on a Pultec EQ, so that as you boost the lows, the lower end of the mid‑range is automatically pulled back to prevent it becoming too congested. The centre position on the cut/boost toggle switch is used to bypass this EQ section, and a further switchable‑frequency low‑cut filter is available to remove excessive lows.
There's also a dual‑filter approach to controlling the highs, with a variable‑width peaking filter normally used for boosting and a shelving filter usually used to attenuate. As with the low end, it is the interaction of these two filters that creates the magic, in that the more HF attenuation is applied, the more selective the peaking filter becomes, so that the filter's centre frequency is boosted more as more shelving cut is applied. There's also a switchable low‑pass filter in this section. Note that extra interim filter frequencies are available between each of the marked positions on the various frequency knobs, so there are more frequency settings than the controls initially indicate. Also on the panel is a master level control, a small adjuster for the valve emulation, to alter the amount of 'attitube' (I just thought of that one!) and a three‑way switch labelled Valve/Clear/Off. When this is in its Off position, all the filters are bypassed, at the Clear position the filters are on but the valve emulation is bypassed, and in Valve mode you get the filters and the valve.
PSP NobleQex, the second plug‑in of the set, is basically a PSP NobleQ equipped with a mid‑range band‑pass filter and something PSP call an adjustable low‑shelf dip frequency shift, operated via the Attenuation Shift control in the low section. I asked Antoni at PSP exactly what this did and he said: "It actually shifts the low-shelf attenuation filter up and down by one octave”, although the resulting frequency dip is apparently settings‑dependent, so you just have to adjust it by ear. There's nothing unusual about the mid-range section, other than that it has a cut/boost switch rather than the more familiar centre‑flat, cut/boost knob found on most modern parametric equalisers. You get separate controls for frequency (switchable in steps from 150Hz to 5kHz), amount of cut or boost and bandwidth, with the option to bypass the section, using the centre switch position, if it's not required.
I like how PSP have taken the musical aspects of vintage passive equalisers without feeling the need to recreate their specific flaws or to limit the control range just to be faithful to the originals. The NobleQ is all about vibe, not about emulation, and that really comes across in its smooth, musically expansive tonality. Its tube emulation fattens bass sounds in a very elegant and satisfying way, seeming also to add definition, while the upper shelf frequency works well on high frequencies such as those in cymbals or acoustic guitars, to add a musical sheen to the sound without becoming abrasive. If I have any criticism of the plug‑in, it is one that applies to all similar equalisers, and that is that the user could really benefit from a display showing what the EQ curves actually look like, as the control interactions are sometimes a little too complex to be entirely intuitive. (The counter‑argument is that too many people already mix with their eyes, and I'd go along with that, but in the case of analogue equalisers with non‑obvious control interactions, I still think a response graph could be very educational.)
Sonically, these two equalisers are amongst the best and most 'analogue‑sounding' EQ plug‑ins I've used to date, and I'd have no hesitation in using them for mastering, as well as track and group processing when mixing. Even a gentle application makes sounds appear more solid and present, something that is often missing from a digital mix, while the way they are able to smooth the highs without losing presence is extremely appealing. It is often said that a good processor helps glue the various elements of a mix into a cohesive whole, and these equalisers do exactly that. If you need EQ that can polish as well as add weight and finesse to your mixes, this pair of plug‑ins from PSP will take a lot of beating.