Hieroglyphic Opalina is a unique stereo state-variable filter network that functions as a CV-controllable resonator or isolator.
Following the unique allpass filter-powered Smoothie Audio Smear, I’ll continue with another special Eurorack filter. When you hear the name filter, you usually think of the classic low-pass or high-pass filter. But filters can do far more exciting things than just that.
With Opalina, Hieroglyphic has released a stereo analog filter module for Eurorack that doesn’t do the obvious stuff.
Hieroglyphic Opalina
Opalina is a new 14HP analog stereo state-variable filter module that can function as a resonator or an isolator. It has a completely analog signal path. With a simple button and dedicated mode LEDs, you can switch between the two modes.
In Resonator mode, the stereo filter is configured as a triple-bandpass filter, emphasizing resonant peaks and formants with a -12 dB/oct filter slope.
Different in the Isolator mode. Here, the slope is -24dB/oct and is a cascaded state-variable filter, offering a variable mid-bandwidth for use as a resonant crossover.
The module has a big frequency knob and six faders with which you can control the low, mid, high, – fm+, span, and resonance. Each parameter is manually controllable or via a dedicated CV input.
Opalina provides independent outputs for each band in both left and right channels, along with a stereo-sum output pair. The latter also offers a soft-clipping circuit. Further, it includes a 2HP expander for independent filter inputs.
First Impression
Resonators and isolators are nothing new to the Eurorack format. Opalina, however, offers them in a very immediate, fun format with manual and CV-controllable parameter control. In DivKid’s video, it sounds lovely.
Those who want both sound-shaping tools in one package, in analog format, might find what they’re looking for here.
Hieroglyphic Opalina is available now for $369 / 290€ + VAT/£ 308, with a silver or black faceplate.
More information here: Hieroglyphic
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