The Walrus Audio Slöer is a stereo ambient reverb pedal that builds on the company's Slö lineup, adding two additional reverb algorithms, stereo width control, two additional modulation wave shapes, and the ability to run in stereo1. Where the original Slö was a compact, mono reverb designed to deliver a textural, rather than realistic, effect ideal for music with ambient and drone qualities, the Slöer is the stereo version of the Slötva, with a footprint almost twice as big as the original Slö and two faders in the heart of the pedal2. Walrus Audio describes it as a tool for creating "immersive, lush, modulated, sleepy, and ambient soundscapes with more width and depth than ever before"3.
What the Slöer does: five reverb modes
A five-way rotary dial selects the reverb algorithm. Three modes carry over from the Slö, and two are new1:
| Mode | What it does | What the X control does |
|---|---|---|
| Dark (Lower Octave) | Adds a lower octave to the reverb trail for deep, wide atmospheric sounds | Sets the level of a -1 octave signal that feeds the reverb2 |
| Rise (Ambient Swell) | Auto-swell reverb for cinematic swells | Sets how long the reverb takes to swell in after a note, lower for shorter rise times2 |
| Dream (Latching Pad) | Applies a latching pad function to a lush reverb | Mode-dependent28 |
| Rain (Delay Tap Diffusion) | Lower diffusion lets the delay taps audibly create an echo-like effect within the reverb | Sets the amount of diffusion of the delay taps24 |
| Light (High Octave Shimmer) | Bright, smooth reverb with an octave-up shimmer | Controls the level of shimmer: low for a smooth pad-like reverb, higher for a bright shimmer24 |
Secondary functions on the dial change between five different wave shapes for modulation on the reverb trail9. The original Sine, Warp and Sink shapes are joined by two new additions, Square and Random4. Holding the bypass switch and changing the Depth control alters the rate of the modulation as well4.
Controls and the two sliders
The control set is Decay, Filter, Depth / Rate, Mix, a Wide/Medium/Narrow stereo Width mini toggle, X and Stretch sliders, the reverb and modulation Mode dial, and Bypass and Sustain footswitches4. The two faders set the inherited, mode-dependent X parameter and the new Stretch function, which changes the reverb's sample rate for lo-fi effects10.
The Width mini toggle selects between Wide (individual signals to the left and right channels), Medium (a milder stereo diffusion spread) and Narrow (parallel mono) for the stereo field in the left and right channels4. MusicRadar's reviewer found that with the Width toggle, "the differences are dramatic."4
Sustain and bypass footswitches
The Sustain switch, when pressed, ramps the reverb trail up to maximum and then ramps back down to the decay knob setting when released; in the Dream algorithm it is latching2. The Bypass switch has a secondary function: when the pedal is off, press and hold to temporarily activate the effect and add a moment of reverb texture, and releasing turns the effect off and fades it out2.
Presets
The Slöer holds three onboard presets. Save one by simultaneously pressing and holding down the bypass and sustain switches, and scroll through the presets by simultaneously pressing and releasing bypass and sustain1.
Mono and stereo setups
The Slöer can be run Mono In/Mono Out, Mono In/Stereo Out and Stereo In/Stereo Out setups6, so it works on a mono board as well as in a full stereo rig. There is no MIDI and no expression pedal control4.
The Slöer runs on a 9V DC center-negative supply drawing 100mA minimum, with the power supply not included34. There is no battery option, and the 100mA draw is worth checking against a small daisy-chain supply before powering it alongside other digital pedals.
History and versions: from the Slö to the Slöer
The Slöer is the third addition to Walrus Audio's Slö selection, following the flagship Slö and the upgraded Slötva, and Guitar World described it at launch as an updated take on the brand's popular Slö unit that finally offers stereo functionality6. Guitar World's reviewer Trevor Curwen put the lineage simply: "the Slö reverb begat the Slöer."11
The Slöer is the third addition to Walrus Audio's Slö selection, following the flagship Slö and the upgraded Slötvå, and Walrus Audio describes it as the stereo version of the Slötvå6102. It launched at $3495, and the maker's own listing puts the list price at $349.995.
Alongside the two new algorithms, the Slöer adds reverb sample rate controls in the Stretch slider, which MusicRadar's reviewer Rob described as "a new parameter that manipulates the sample rate of the digital signal processing."412
What reviewers said
MusicRadar's review concluded that "One of the very best ambient reverb pedals around just got even better, Walrus has expanded the sounds and controls for" the pedal4. The reviewer found the sustain switch great for solo jamming, and called the pedal exceptionally good for creating pad tones to loop and jam over, a big part of its appeal4. Of the new Rain mode, the reviewer wrote, "It's also become my go-to mode on this pedal."4 On price, the review noted both sides: "It's a higher price for an ambient reverb but a great one."4
"Tappy and trippy, this program creates a unique effect with lower levels of diffusion allowing the reverb, delay taps to audibly create an echo-like effect within your reverb"
At launch, Gearnews wrote that Walrus Audio makes some great effects pedals and that the new Slöer Stereo Ambient Reverb looked to be one of them, as it added all the good stuff overall12. In buying guides, Guitar.com named the Slöer its Best stereo ambient reverb in January 202513, and Delicious Audio's ambient and shoegaze reverb guide listed it at $349 as the stereo version of the Slötva with the two new Rain and Light algorithms10. Gearnews' 2026 ambient reverb buying guide listed it at $345.0014.
Where it sits in the Walrus Audio range
The Slöer is the stereo, expanded member of the Slö family, which also includes the mono Slö and Slötva. For players who want a more conventional reverb rather than a textural ambient one, Walrus Audio also makes the Fathom multi-function reverb and the Mako Series R1 high-fidelity stereo reverb, and the limited Lüm Texture Engine granular reverb draws on elements of the Fable, Lore and Slötva pedals. The Slöer covers reverb, modulation and filter territory in one box3.
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Questions
Does the Walrus Slöer have MIDI or expression control?
No. The Slöer has no MIDI and no expression pedal control. Everything is done from the knobs, sliders, toggles and footswitches on the pedal itself, plus the three onboard presets. Players who need MIDI or expression control would have to look at other pedals in Walrus Audio's range.
What is the difference between the Slö and the Slöer?
The Slöer builds on the Slö lineup but adds two additional reverb algorithms, Rain and Light, stereo width control, two additional modulation wave shapes, and the ability to run in stereo. Its footprint is almost twice as big as the original Slö, with two faders in the heart of the pedal for the X and Stretch parameters.
Can the Walrus Slöer run in mono?
Yes. The Slöer can be run Mono In/Mono Out, Mono In/Stereo Out and Stereo In/Stereo Out setups, so it works on a mono board as well as in a stereo rig. A Width mini toggle selects between Wide, Medium and Narrow stereo settings.
How do you save presets on the Slöer?
The Slöer holds three onboard presets. Save one by simultaneously pressing and holding down the bypass and sustain switches, and scroll through the presets by simultaneously pressing and releasing bypass and sustain.
Is the Walrus Slöer true bypass?
No. The Slöer uses buffered bypass rather than true bypass. With a buffer in the signal path, the pedal stays active in its bypassed state, which some players prefer on long cable runs and others factor into their ordering of pedals.
Sources (14)
- Slöer Stereo Ambient Reverb, Walrus Audio
- Walrus Audio Slöer Stereo Ambient Reverb, Delicious Audio, 2023-11-15
- Slöer (Black) by Walrus Audio, RockBoard (www.rockboard.de), 2026
- Walrus Audio Slöer Stereo Ambient Reverb pedal review, MusicRadar, 2023-11-23
- Slöer Stereo Ambient Reverb, Walrus Audio
- Walrus Audio has finally issued a stereo version of its Slö reverb pedal, Guitar World, 2023-07-18
- Walrus Audio Slöer Ambient Reverb, Premier Guitar, 2023-07-18
- Walrus Audio takes guitar tone deeper into the ambient reverb rabbit hole with Slöer, MusicRadar, 2023-07-18
- Slöer Stereo Ambient Reverb, Black Friday 2024 Floral Series, Walrus Audio
- The Best Ambient-Shoegaze Reverb Pedals In 2024, Delicious Audio, 2024-11-15
- Walrus Audio Monumental Harmonic Stereo Tremolo review, Guitar World, 2024-07-10
- Walrus Audio Slöer Stereo Ambient Reverb: Now with Stretch, gearnews.com, 2023-07-18
- The best pedals for ambient music, from space-warping reverbs to experimental micro-loopers, Guitar.com, 2025-01-24
- The 7 Best Ambient Reverb Pedals for any Budget: From Subtle Space to Full Void, www.gearnews.com, 2026-06-22
