Zoom B2 FOUR Bass Multi-Effects Processor

The Zoom B2 FOUR is a bass multi-effects processor that combines effects processing, amp and cabinet emulation, DI modeling, practice tools, and USB audio connectivity in one floor unit. It is designed for bassists who want to move between different tones without assembling a large pedalboard. With balanced, stereo, headphone, auxiliary, and USB connections, it can support rehearsal, recording, direct-to-PA performance, and bass-amp setups.

The B2 FOUR gives electric and acoustic bass players a practical way to shape a complete signal path from one device. Its switchable 1 MΩ or 10 MΩ input impedance accommodates regular electric basses as well as upright or acoustic basses using piezo pickups. A selectable DI section can remain part of the sound when the effects section is bypassed.

Its sound palette includes 104 effects, made up of bass effects, preamp models, and amp/cabinet models. Up to five effects can be used simultaneously in a patch, with settings stored in 300 user patch memories. The unit also includes 250 factory presets designed around historic bass tones.

Eleven amp and cabinet models use Zoom Multi-Layer IR technology, which changes cabinet impulse-response behavior across three playing levels. This approach is intended to reflect changes in cabinet character as bass dynamics rise and fall. Six DI models provide three tube-style and three solid-state-style direct-box voicings for different low-end response and attack characteristics.

The B2 FOUR also works as a practice and recording hub. A looper supports mono loops up to 60 seconds, and the onboard drum machine provides 68 rhythm patterns. USB-C connectivity supports USB bus power, Handy Guitar Lab management, firmware updates, and 32-bit 2-in/2-out USB audio interfacing with compatible computers and mobile devices.

Key Features

• 104 Effects And Models: Combines bass effects, preamps, and amp/cabinet models for flexible signal shaping.
• Six DI Models: Select from three tube-style and three solid-state-style DI voicings.
• Multi-Layer IR Technology: Uses cabinet responses captured at three volume levels for dynamic amp/cab simulation.
• Five Simultaneous Effects: Build a complete patch with up to five effects active at once.
• Built-In Practice Tools: Includes a 60-second looper and 68 onboard rhythm patterns.
• USB Audio Interface: Provides 32-bit, 2-in/2-out USB audio through its USB-C port.

Design & Installation

The B2 FOUR uses a compact floor-processor format with foot-operable direction buttons, footswitches with status indicators, four rotary encoders, a dedicated DI Model switch, and a 256×128 dot-matrix LCD. Zoom specifies a 906 g weight and 146 mm depth by 249 mm width by 72 mm height. The manufacturer does not specify the enclosure material.

Connect a bass to the 1/4-inch INPUT, then route the LEFT/RIGHT outputs to a bass amp or powered monitors, or use the XLR BALANCED OUTPUT for a PA or interface. The 10 MΩ input setting is intended for piezo-equipped acoustic or upright basses, while the 1 MΩ setting is for regular electric basses. Use the specified Zoom AD-16 9V DC adapter or supported USB bus power, and use a USB-C data cable when connecting to a computer, smartphone, or tablet.