Behringer BM-13 PHASER: Classic Phase, Modern Mojo

Central to the BM-13’s appeal is its 12-stage phasing circuit, which can be switched down to 6 stages for subtler effects. The video offers a concise explanation of phaser topology: the signal is split, one half passing through a cascade of all-pass filters—twelve in this case—while the other remains dry. When recombined, these paths produce a series of notches in the frequency spectrum, with an LFO sweeping the notches for that signature phase movement.

The ability to toggle between 12 and 6 stages isn’t just a numbers game—it’s a practical tool for tailoring the complexity of your sound. More stages mean more notches and a denser, more intricate phase texture, while fewer stages yield a gentler, more classic sweep. This flexibility is demonstrated in the video with audio examples, underscoring the BM-13’s range from subtle shimmer to full-on psychedelic swirl.

The BM-13 doesn’t skimp on tweakability. Up top, you’ll find drive and output controls for shaping both input gain and final output, making it easy to dial in anything from clean phase to saturated analogue warmth. The sweep and resonance knobs allow for precise sculpting of the phaser’s frequency range and intensity, while a rocker switch lets users flip between 6- and 12-stage operation on the fly.

Where things get especially interesting is the LFO section. Unlike many phasers, the BM-13 provides a dedicated LFO range switch, rate, and amount controls, giving users deep access to the movement and modulation at the heart of the effect. The video highlights the pedal’s comprehensive CV and expression pedal connectivity, enabling external modulation of parameters like sweep and resonance. This opens the door for integration with modular synths or other control sources, making the BM-13 a flexible tool for both pedalboards and Eurorack-style setups.

One of the BM-13’s standout features is its stereo capability, achieved by running the main and aux outputs to separate speakers. The aux output delivers the same effect as the main, but with a phase shift, resulting in a wide, immersive stereo image when panned left and right. The video demonstrates this with a clear before-and-after comparison, highlighting how the effect transforms a mono instrument into a swirling, room-filling experience.

This stereo trickery isn’t just for show—it’s a practical way to simulate rotary speaker effects or add movement to static sources. Behringer’s demo makes it clear that the BM-13 isn’t limited to traditional pedalboard duties; it’s equally at home as part of a larger, more experimental setup where stereo imaging and spatial modulation are key creative tools.