The Soundtoys Sie-Q plug-in ($129; soundtoys.com) is an emulation of the W295b, a broadcast-console EQ made by the German company Siemens in the ’60s, which has excellent musical applications. It replicates all the features of the original hardware with a couple of additions, most notably the Drive circuit. You can insert it individually or open it within the Soundtoys Effects Rack plug-in.
Sie-Q is also available in the Soundtoys 5.2 bundle and works in AAX, AU, and VST hosts.
Although capable of significant frequency adjustments, Sie-Q is not suited for surgical-type EQing, where you need to isolate a narrow frequency band. Rather, it’s designed for broader tweaks and polishing.
Just like the hardware it emulates, Sie-Q has single knobs for the High and Low bands and a semi-parametric midrange band. The High and Low bands are unusual in that the type of filtering changes depend on whether you’re boosting or cutting, and the center frequencies vary depending on the setting.
The Low band functions like a low-shelf filter when cutting and a bell-shaped filter when boosting. The High band is a lowpass filter when cutting, and a bell-shaped filter when boosting. On the original, the High and Low knobs were stepped, but on the plug-in they are continuously variable.
The Mid band features six well-chosen frequency settings—0.7, 1.0, 1.5, 2.3, 3.5 and 5.6 kHz—that can be boosted or cut by 8 dB.
The Drive circuit can boost or cut gain by 15 dB and is located before the output amplifier in the signal chain. Boosting creates saturation, which can range from subtle to extreme; in the case of the former, the saturation is pleasing and musical. The Auto Gain feature helps you keep the volume under control when boosting.
Soundtoys describes Sie-Q as being “gentle and musical,” and that was certainly borne out in my testing. Whether I used it to add a finishing touch to a vocal, to EQ and saturate snares and kicks, to punch up a blah drum loop, or to sweeten an acoustic or electric guitar, it almost always gave me satisfying results.
Overall, Sie-Q is unique and versatile, and I highly recommend it.