Walrus Audio Lüm Guava

A "texture reverb" at the crossroads of Slö, Lore, and Fable

The Lüm was designed as a reverb that breaks away from the classic framework: instead of just creating a large space, it fragments your signal into micro-samples (the so-called "grains") and then wraps them in layers that seem to evolve with each attack. Its DNA is inspired by the ambient and cinematic aesthetic of the Slö, the shadow and light movements with reverse effects like the Lore, and the exploratory granular approach of the Fable.
The result is a pedal that sits as much on the guitar effect side as on the side of a sound design tool: it deliberately blurs the boundary between the played note and the surrounding environment, with a sensation of living material, sometimes sporadic, sometimes incredibly immersive.

Who it's for, and in which styles the Lüm makes a difference

The Lüm is aimed at guitarists (and more broadly any mono source) who want to go beyond traditional "room/hall" reverb. It is particularly comfortable in ambient, shoegaze, post-rock, experimental indie, film music, drones, and anything that requires moving reverb tails that tell a story.
In the studio, it becomes an excellent layer and transition generator, perfect for doubling a take, creating a misty intro, or transforming a simple pattern into a landscape. Live, its presets and Moment Control allow you to "play" the effect like an instrument, without letting go of the neck, for swells, switches, and ultra-musical accents.
Placement tip: in Mode II, the Lüm can be delightful before an overdrive or distortion for a more organic and explosive texture. In a more traditional chain, placed at the end of the pedalboard, it excels at painting vast depths without completely masking the attack.

Controls, modes, and setting ideas to sculpt your space

The Lüm offers 3 programs selected via a mode switch, and an interface designed for speed while remaining very flexible. There are five potentiometers dedicated to texture creation: Decay (decay time and temporal parameters depending on the mode), Filter (synth-style low-cut to darken or soften), Mix (dry/wet blend), X (grain size in Mode I and II, and control related to the reversed reverb in Mode III), and Stretch (time-stretching engine by globally changing the sample rate).
Mode I - Grain Cloud: a granular cloud built from taps reading a feedback delay line. Here, the X control manages grain size, thus the frequency at which "glitches" appear. Layered with chorus, tremolo, or delay, this mode opens very novel territories.
Mode II - Grain Verb: the reverb becomes a kind of bath in which the grains fully blend. The texture is denser, more enveloping, and the X control also adjusts grain size. This mode is formidable for thickening a guitar in chords or creating a continuous carpet behind a melody.
Mode III - Forward / Reverse Verb: a "forward" reverb that dives into a reversed reverb, with an almost playful and rhythmic interaction. The Stretch knob allows you to modify the speed of this interaction, while X controls the behavior of the reversed reverb.
Regarding footswitches, the Lüm combines a classic Bypass and a Moment switch: holding Moment activates an automation glide on one of the five knobs, sliding the current setting toward a defined target. To dose the nervous or airy character of the automation, a Ramp setting lets you choose the transition time between 10 ms, 1000 ms, and 5000 ms.
The 3 built-in presets (Red, Green, Blue) can be recalled with your foot, and sounds can blend more naturally when staying on the same algorithm. Handy for moving from a subtle halo to a gigantic wash without harsh cuts, especially if you use the bypass in Trails mode. Conversely, the Instant Cut mode is perfect for sharp stops, breaks, and very clean "stutter" effects.

Sound Character

The Lüm does not seek "studio" transparency at all costs: it aims for a textural signature, with tails that sparkle, fragment, and recombine, sometimes as nervous micro-glitch grains, sometimes as a dense, plush mass. The global low-pass filter is a real asset for placing the effect in the mix: you can keep the attack clear while pushing the ambiance to the back, or conversely darken heavily for velvety, almost synthetic pads.
Its dynamics are particularly inspiring when playing with the Mix and Moment automation: a simple sustained note can transform into movement, reverse suction, or granular fog that lives its own life. On Equipboard, the Lüm is notably spotted in Dylan Carlson's rig, proof that it has its place in worlds where guitar becomes landscape.

Technical specifications

Effects	Reverb	Type	sector
Technology	Digital	Use	electric guitar
Format	Pedal	Color	Pink
EQ	Filter

3 modes	Mode I "Grain Cloud", Mode II "Grain Verb", Mode III "Forward / Reverse Verb"	Input	1 x 6.35mm TS Jack
Stretch engine	global sample rate variation from 0.5x to 2x	Output	1 x 6.35mm TS Jack
Potentiometers	Decay, Filter, Mix, X, Stretch	Input impedance	1M Ohms
Bypass footswitch	effect on/off	Output impedance	100 Ohms
Moment footswitch	momentary automation (glide) assignable to one of the 5 potentiometers	Dimensions (including potentiometers)	121 x 66 x 35 mm
Ramp setting	10 ms, 1000 ms, 5000 ms	Power supply	not included
Up to 3 built-in presets	Red, Green, Blue	Required power supply	9V DC center negative
Selectable bypass modes	Trails or Instant Cut	Required current	minimum 100 mA
Bypass type	buffered bypass