SolidGoldFX Horizon Compressor Review

An optical compressor that goes way beyond a gentle squeeze.

As we’ve discussed before in these pages, compression can be tricky to understand and easy to misuse. And when you explore SolidGoldFX’s Horizon optical compressor from one extreme of it’s performance parameters to another, it’s easy to see how a compressor’s raison d’être could be elusive to newbies.

But, boy, does the Horizon make the mysteries of compression sound cool. It can, at many settings, audibly transcend the boundaries of compression—suggesting tasty volume swells, bowing effects, and tape manipulation—with just three simple knobs. It’s a great example of all the strange and wonderful things compression can be—all while excelling at the fundamental tasks any good compressor should manage.

Light and Sound Construction
For the uninitiated, an opto-compressor uses a lamp and a light-sensitive receptor (which translates light to voltage) to represent and communicate increases in gain. Compared to, say, a digital circuit, which can represent those changes with numeric precision, an optical circuit is full of non-linear ambiguities and latencies that translate to a lovely, vocal musicality. Horizon’s LED-based optical circuit leverages these quirks in many cool, often intoxicating, ways.

It’s not often a compressor can be an actual compositional tool, but the blooming notes from a super-squeezed Horizon can totally and musically transform the simplest chord sequences and riffs.

Outwardly, though, Horizon looks and feels like a no-nonsense, locked-down, and elegant piece of construction. Stout controls move with a smooth, satisfying resistance that’s ideal for dialing in and holding very precise adjustments. You won’t find out much about the Horizon by opening up the unit—the circuit board is flipped, obscuring a look at individual components. Solders, however, are immaculate and robust. There’s also room for a 9V battery if you’re AC-power averse.

St. Lawrence Swells
You don’t have to move too far beyond the most modest compression and attack settings before you hear and feel the ways Horizon is more colorful and extroverted than the average pedal comp’. The soft, liquid bloom that is optical compression’s sonic calling card is quite pronounced, but seamlessly integrated with the complete tone. These differences are a blast to monkey around with. It’s not often a pedal compressor can be an actual compositional tool, but the blooming notes from a super-squeezed Horizon can radically—and very musically—transform simple riffs, chords, or triads.

Advancing the compression and attack controls (the latter is the real key to piling on that fluid, flowering quality) to their higher reaches can be downright psychedelic—imparting squeeze-’til-it-oozes-like-melted-marshmallow, Beatles-’66 tones and traces of volume pedal swell, opiated auto wah, and reverse tape textures. Better still, it works at these heavier settings very quietly. Players that love the Boss CS-3’s surreal sustain and squish but don’t love that unit’s noisy, tone-altering tendencies will dig the Horizon’s ability to maintain relative transparency in extreme settings.


Great range. Tons of unique sounds. Cool interactivity between controls.

May be too vague or colorful for players that like to fine-tune subtle comp tones.


Ease of Use:




SolidGoldFX Horizon Compressor

Slower attack settings are also very effective. Mated to heavy compression settings, they give quacky, out-of-phase Stratocaster tones a little extra snap and sustain. Suddenly I could pepper funky double-stop vamps with ringing, open drone strings that seemed to hang around for an eternity—a new twist on the same old “Lay Down Sally” tone for sure.

Humbuckers react beautifully to the Horizon’s ability to maintain clarity and harmonic complexity while keeping bossier overtones in check. The ringing harmonics and semi-hollow resonance of Rickenbackers with “toaster” and Hi-Gain pickups were, predictably, a heavenly match—especially with big, clean 6L6-powered amplifiers. Horizon also works in very cool ways with fuzz and distortion—adding a really nice smoothing quality on the downstream side of a hectic fuzz and enabling splintered and radical fuzz tones at low volume when placed out in front.

The Verdict
SolidGoldFX’s intuitive, interactive Horizon illustrates everything that’s great and musical about compressors that work in less-than-totally-linear ways. It’s a quick and easy-to-use means of enlivening otherwise staid tones. And if you switch between guitars to exploit the strength of their individual voices, you’ll love the subtly transformative and exaggerating effects it can have on those sounds.

For sound sculptors that favor hyper-precision and predictability, the Horizon may feel a little vague through much of its range. (I love this facet of its capabilities.) Others may prefer that a compressor offer more control over release times. And some of the Horizon’s nuance might be lost on players that like a Ross or Dyna Comp’s set-and-forget simplicity. But if you savor adventure and a sense of dreamy drift on top of your pretty tones, the Horizon is about as much fun as you can have with a compressor short of working with powerful, high-end studio units—without sacrificing an ounce of utility.

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