A Compact Way to Add More Effects to Your Bass Rig
BOSS has just announced the EX-4 Effects Expander, a small multi-effects unit designed to add more options to an existing pedalboard without forcing you to rethink the whole thing. That makes quite a bit of sense for bass players: the EX-4 packs 120 BOSS effects into a 117 × 138 mm enclosure, including bass-tuned effects, overdrives, modulation, delays and reverbs, and can run up to four effects at the same time.
What makes the EX-4 particularly interesting as a pedalboard addition is its routing. The built-in send/return can be placed anywhere in the signal chain, so you can bring your existing pedals into the EX-4 rather than treating it as a separate unit. BOSS also includes a global EQ, foot volume and two noise suppressors, while series, parallel and wet/dry configurations give you considerably more control over how effects interact with your bass signal.
The EX-4 is also clearly aimed at players who want more control without putting a full-sized multi-effects processor on the floor. It has a 2.4-inch colour display, four dedicated FX buttons and two configurable footswitches, with Manual and Memory modes available depending on how you want to use it. There are 128 preset and 128 user memories, along with TRS MIDI, an expression/footswitch input and stereo I/O. For a bassist running a relatively traditional board, it could be an interesting way of adding modulation, ambient effects or more experimental sounds without filling the board with individual pedals.
The BOSS EX-4 is expected to be available in October 2026. It weighs 800 g and measures just 117 × 138 × 65 mm with its rubber feet, making the footprint one of the more interesting parts of the package. We haven’t had a chance to put one through a bass rig yet, but we’ll be particularly interested to see how useful those bass-specific effects and the flexible routing prove in a real-world pedalboard.
