Zoom B1 FOUR Bass Multi-Effects Processor

The Zoom B1 FOUR is a compact bass multi-effects processor for players who want to build and recall a range of bass sounds without assembling a large pedalboard. It combines bass-focused effects, amplifier and cabinet modeling, rhythm accompaniment, and looping in one floor-ready unit. It is suited to home practice, rehearsals, recording setups, and streamlined live rigs.

Its sound-shaping approach covers practical bass essentials such as dynamics processing, EQ, modulation, drive, synth-style tones, ambience, and amp-style voices. The B1 FOUR supports more than 60 built-in effects and 9 amp models, allowing players to move from clean foundational tones to more processed textures. Up to five effects can be used at once and arranged in any order within a patch.

The onboard looper and rhythm section make the unit especially useful for independent practice. It can record loops up to 30 seconds or 64 beats, with seamless loop start and end points, while 68 built-in rhythm patterns provide accompaniment across multiple time signatures. A chromatic tuner is also built in for quick tuning between songs or practice sessions.

Zoom Guitar Lab software expands the editing workflow beyond the pedal itself. Through the USB Micro-B connection, users can manage, back up, and edit patches, as well as download compatible additional effects. The B1 FOUR stores up to 50 user-created patches for organizing sounds by song, instrument, or playing situation.

The B1 FOUR fits easily between a bass and an amplifier, powered speaker, mixer input, or headphones. Its combined stereo output/headphone jack supports quiet practice as well as connection to an amp, and the AUX IN accepts an external music player for play-along use. Power options include four AA batteries, an optional Zoom AD-16 adapter, or USB bus power.

Key Features

• Bass Effects Library: More than 60 built-in bass effects provide tools for tone shaping, dynamics, modulation, drive, and ambience.
• Nine Amp Models: Amp and cabinet models help create bass-rig-inspired sounds without requiring multiple amplifiers.
• Five-Effect Signal Chain: Use up to five effects simultaneously and place them in the order that suits your patch.
• Looper And Rhythms: Build loops up to 30 seconds or 64 beats and practice with 68 built-in rhythm patterns.
• Guitar Lab Support: USB connectivity enables patch management, backup, firmware updates, and compatible effect downloads through Zoom Guitar Lab.
• Flexible Powering: Operate from four AA batteries, optional 9V DC power, or USB bus power for adaptable use.

Design & Installation

The B1 FOUR uses a compact floor-format design that can also be placed on a desktop for editing. It measures 156 mm deep by 130 mm wide by 42 mm high and weighs 340 g without batteries. Zoom specifies a 128 x 32 dot-matrix LCD for viewing patches and settings; the manufacturer does not specify enclosure material.

Connect a bass with a standard mono 1/4-inch instrument cable to the INPUT jack, then connect the combined OUTPUT/headphone jack to an amp, mixer-compatible input, or headphones as appropriate. The AUX IN accepts a stereo mini-jack connection from a music player for practice, and USB can supply power while also supporting USB MIDI functions. For standalone use, install four AA batteries; for fixed setups, use the optional Zoom AD-16 9V DC, center-negative adapter.