From the very first moment I plugged into the Sinkhole, I knew I was going to love it and I knew I was going to put some filthy distortion behind it. It’s a modulated reverb built for washed-out, hazy sounds: the kind of verb that turns a chord into a swimming pool of texture.
What makes it distinct is a four-voice chorus sitting inside the reverb trail. That chorus and the feedback path interact in ways that range from subtle shimmer to rich, psychedelic auto-filtering. Turn up the decay and it starts generating synth-pad-like tones matching whatever you play. I like it standalone for ambient noodling, but it really shines with distortion in front of it.
Five knobs across two rows, reading left to right: top row is Fdbck, Mod, Verb; second row is Mix on the left and Vol on the right.
Fdbck controls feedback amount and chorus depth together, shaping the chorus voices from comb filtering through pseudo-phaser to haunting auto-filtering. Mod sets the LFO rate. Verb sets decay time, up to a near-infinite freeze at maximum. Mix is the wet-dry blend. Vol is an onboard preamp that can also act as a clean boost.
In the demo above I’ve set up sweeps for Fdbck, Mod, and Verb, so you can hear exactly what each one does in isolation.
The three main presets map the core range. Lush Swirl (Fdbck 6, Mod 6, Verb 7, Mix 6) is the sweet spot for shoegaze wash: long decay, moderate modulation, enough mix to float over distortion without drowning the attack. Psychedelic Hall (Fdbck 7, Mod 9, Verb 2, Mix 6) is counterintuitive: short decay but fast, deep modulation, which creates a swirling, almost phaser-like movement in the tail. Subtle Ambience (Fdbck 2, Mod 10, Verb 9, Mix 4) pushes the modulation rate to maximum with long decay and a conservative mix, landing in gentle, hazy territory that sits behind a clean guitar without calling attention to itself.
The “This was made for Shoegaze!” preset pairs the Sinkhole with the Twilight Pulse AudioWorks Proxima: Proxima gain at 9 into Fdbck 8, Mod 5, Verb 5, Mix 6. What stands out is the note clarity: even through that much high-gain fuzz, chords and arpeggios stay legible over the washed-out textures.
The Sinkhole also appears in the FX Loop preset of the Orange Tour Baby 100 and the Ambient Miniboard preset of the Old Blood Noise Endeavors BL-44 Reverse, if you want to hear it as a chain component.
The Walrus Audio Slö is the natural cross-shop for modulated ambient reverb. Both pedals target lush, textural territory, but they get there differently. The Slö offers three distinct algorithms: Dark adds a sub-octave into the reverb trail, Rise builds an auto-swell so the tail comes in after your attack, and Dream produces a lush modulated reverb with a Sustain footswitch for infinite freeze.
The Sinkhole doesn’t have discrete modes: all five knobs interact continuously, and the four-voice chorus embedded in the reverb path produces modulation that’s more complex and less predictable than the Slö’s waveform-based approach. The Slö is better if you need specific tools: a sub-octave reverb or a swell effect aren’t things the Sinkhole does. For straight shoegaze wash and psychedelic swirl the two are genuinely competitive, but the right choice comes down to whether you want flexibility of character (Sinkhole) or flexibility of mode (Slö).
This is built for shoegaze, ambient, and post-rock players. The chorus-in-reverb voicing means the reverb itself moves and breathes rather than just decaying, which is what makes it feel more like a synth pad than a room. I have a feeling the Sinkhole will become an integral part of my arsenal, especially for shoegaze and ambient music.
If you want conventional hall, plate, or spring reverb, this isn’t the right tool. If you need stereo output or an expression input, it won’t cover those either. But for washed-out, animated reverb textures, it delivers.
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