The Electro-Harmonix Oceans Abyss, sold as the Oceans Abyss Advanced Reverb Laboratory, is a digital reverb and multi-effects workstation released by Electro-Harmonix in 20251. It is built around two independently programmable reverb engines running full-stereo algorithms, and it replaces the Oceans 12 as EHX's flagship reverb workstation23. Guitar Pedal X described it as the company's new flagship in a format similar to its recent POG33.
The core idea is that both reverb engines are available at once, each fully pannable in the stereo field, and each preset can load two reverb algorithms simultaneously24. Around the reverbs sits a customizable signal path with additional FX blocks like Delay, Chorus, Tremolo, or Bit Crusher, which Electro-Harmonix positions as "a truly immersive effects workstation for soundscape building"2. Delicious Audio called it "a complete sound-shaping toolkit for musicians seeking versatile and high-fidelity effects," spanning surf, ambient soundscapes and experimental tones5.
Two stereo reverbs plus effects blocks
Each of the 128 preset memory slots can load two reverb algorithms at the same time, and the two reverbs can be assigned to different stereo pan positions, so one engine can sit left and the other right4. Each reverb has its own mix control, called Blend4.
Beyond the reverbs, there are six effects slots where you can build your own reverb preset from 12 additional effects, according to gearnews.com's review4. The maker's page names Delay, Chorus, Tremolo and Bit Crusher as examples of the FX blocks that can be placed into the customizable signal path2. A stereo effects loop is also included7.
The pedal is controlled by three footswitches: A, Effect and B. Effect activates the pedal, while A and B activate or deactivate a reverb engine or switch between presets4. Pressing A or B bypasses or engages all FX blocks in that group, and pressing and holding A or B triggers infinite sustain for the corresponding reverb2. The dual-action footswitches allow momentary or latching use5.
| Control | What it does |
|---|---|
| A / B footswitches | Bypass or engage all FX blocks in group A or B; hold to trigger infinite sustain on that reverb2 |
| EFFECT footswitch | Toggles between effect mode and global bypass2 |
| NavCoder knob | Rotary and directional navigation through menus, parameters, presets and settings18 |
| Reverb A controls | Pan knob, Blend slider, Pre-Delay knob, Time knob, EQ Low & High sliders, Edit, Moment and Tails buttons2 |
| Illuminated slide pots and buttons | Direct parameter control from the top panel5 |
Editing happens through a high-visibility OLED graphical display, navigated with the NavCoder knob15. An expression/CV input can control nearly any parameter in any FX block5.
The reverb modes
Electro-Harmonix lists 10 reverb types: Room, Hall, Spring, Plate, Reverse, Dynamic, Auto-Infinite, Shimmer, Polyphonic and Resonant2. Delicious Audio reports the same ten types5.
gearnews.com counts it differently: seventeen reverb types, counting the doubled variants, with Spring, Plate, Dynamic, Auto-Infinite, Shimmer, Polyphonic and Resonant each appearing twice, alongside single Room, Hall and Reverse types4. The two counts describe the same pedal; the maker groups the doubled variants under one name each.
Guitar World's reviewer, Trevor Curwen, found the Spring reverb "can get the 'drip' that surf guitarists seek out"6.
"The Spring reverb can get the 'drip' that surf guitarists seek out"
Power and connections
The rear panel carries Send and Return jacks, a Footswitch jack, an EXP jack for expression/CV, L & R output jacks, a power jack, a USB port, and MIDI In and Out jacks2. gearnews.com specifies the MIDI jacks as both 5-pin, and notes USB-C connectivity4. MIDI In supports program change, control change over nearly every available parameter, and Tempo Clock5.
The pedal is supplied with a 9.6VDC / 500mA power supply, and its current draw is 500mA1.
At 500mA, the Oceans Abyss draws far more current than a standard 100mA daisy-chain output supplies. Use the included adapter or an isolated power supply with a high-current output.
Physically, it measures 7.125 x 5.75 x 2.25 inches1 and weighs 800g (1.76 lbs)9. Guitar World lists its origin as USA6.
What reviewers said
gearnews.com's Julian Schmauch rated it 4,5 out of 5,0 and called it "a magnificent-sounding reverb pedal," writing that with a pedal like the Oceans Abyss "we've got a real highlight on our hands!"4. His review compared its dark, epic reverb tails to the Eventide Blackhole, which he described as having set the standard for tails that stretch into infinity4.
Guitar World's review lists its feature set as buffered bypass, 128 presets and tap tempo, at $495 / £4756. MusicRadar lists the launch price as $495 / £475 / €4999. At launch, gearnews.com noted the $495 price on Electro-Harmonix's website and availability at Thomann for 499 euros4.
Videos
EHX
Chords Of Orion
Mark Johnston
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Questions
Is the Oceans Abyss true bypass?
No. The Oceans Abyss uses buffered bypass, not true bypass, according to Electro-Harmonix's product page and Guitar World's review. Buffered bypass keeps the reverb tails and DSP path consistent when the effect is disengaged, and it means the pedal always presents a load to your signal chain rather than hard-switching around the circuit.
Does the Oceans Abyss have MIDI?
Yes. It has 5-pin MIDI In and Out jacks on the rear panel. MIDI In supports program change, control change messages over nearly every available parameter, and Tempo Clock, so you can switch presets, automate parameters and sync time-based effects from a controller or sequencer.
What power supply does the Oceans Abyss use?
It is supplied with a 9.6VDC / 500mA power adapter, and its current draw is 500mA. That draw is well beyond what a 9V battery or a typical low-current daisy chain output can deliver, so plan on a dedicated isolated output or the included supply.
How many presets does the Oceans Abyss hold?
It holds 128 user presets, accessible from the preset footswitches and over MIDI. Each preset can load two reverb algorithms simultaneously, so a single preset can combine, for example, a spring reverb on one side and a shimmer reverb on the other.
Does the Oceans Abyss have tap tempo?
Yes. Guitar World's review lists tap tempo among the pedal's features, and the MIDI input supports Tempo Clock, so time-based parameters can be set by tapping or synced externally.
Sources (9)
- Oceans Abyss, Electro-Harmonix
- EHX Oceans Abyss, Electro-Harmonix (www.ehx.com)
- Guitar Pedal X, Guitar Pedal X, 2025-05-19
- EHX Oceans Abyss Reverb: Monstrous Mega-Reverb and Multi-Effect, gearnews.com, 2025-05-15
- Electro-Harmonix Ocean Abyss Reverb, Delicious Audio, 2025-08-18
- Electro-Harmonix Oceans Abyss review, Guitar World, 2025-08-04
- Electro-Harmonix launches top-end Oceans Abyss reverb pedal, Guitar World, 2025-05-20
- Dive Into the Oceans Abyss Advanced Reverb, Premier Guitar, 2025-05-15
- “At times it can really feel like more of a multi-effects pedal rather than just a straight reverb pedal”: Electro-Harmonix Oceans Abyss review, MusicRadar, 2025-06-20
