Digitally simulating a rotary speaker is ambitious. Because while the fundamentals of the rotary speaker effect couldn’t be much simpler (put speaker on stick, spin, and repeat) the wobbly, swirling, pitch-shifting delights that result are paradoxically complex and hard to replicate. Neo Instruments’ last rotary simulator, the Ventilator, blew our minds. It simulated the sonic intricacies of a Leslie 122 with startling realism. But it also enabled users to fine-tune details like balance between treble and bass horns and virtual microphone placement. The latest version of the Ventilator, the Mini Vent, has fewer features, but its Leslie simulation is no less stunning. And apart from a few hidden programming features that can be a bit tricky, the simpler, smaller version is as convenient and user friendly as can be.

Rotating Speaker Writ Small
The original Ventilator was a smart piece of design, and in it’s own modest and simple way the German-built Mini Vent lives up to its big brother’s high design standards. The super sturdy square enclosure looks uncannily like that of a vintage ProCo Rat 2 and is about the same dimensions. Crack it open and you behold an immaculately tidy and cleverly arranged two-tiered printed circuit array.

The Mini Vent even lent grandeur to the voice of a
thrift store Casio keyboard.

The smaller, top-most PCB is home to the chip that drives the digital processing. Not surprisingly, it’s a formidable looking beast that looks capable of powering a laptop. The same PCB is home to an input gain select switch that can help you better mate the Mini Vent to hot pickups or keyboards.

The control set is much simpler than the five-knob array on the full-size Ventilator. In fact, there are no knobs at all—just a bypass switch and one for moving between slow and fast rotary speeds. A small button on top of the unit enables switching between programmable presets.


Startlingly convincing rotary speaker simulations. User friendly. Factory default settings are excellent. Gain scheme can be reprogrammed to accommodate hotter or quieter instruments. Built like a rock.

Hard to justify the cost for occasional use.


Ease of Use:




Neo Instruments Mini Vent

The two factory default presets, which simulate close and more distant microphone placement are all most players will need. But if you want to fine-tune the output and better match the pedal to an instrument, amplifier, or effects rig, you can program the pedal by using the footswitches and following the instructions in the manual.

Kandy-Koated Karamel Swirl
If you’ve struggled with trying to approximate rotary speakers through more cost-effective means like phasers, vibrato pedals, and Uni-Vibe-style pedals, the Mini Vent will probably mark an end to most of your frustrations. It’s an incredibly convincing and authentic simulation. The simulation of speaker acceleration and deceleration when you switch from slow settings to fast is excellent. It’s also exceedingly responsive to dynamics, whether it comes from your picking technique or a fuzz placed before the Mini Vent (warning: The latter setup is extremely intoxicating and addictive).

On tape (or a digital equivalent) it’s all but indistinguishable from the real thing—especially in an ensemble. And onstage it only suffers at close proximity—and only then because you won’t hear the mechanical whirring of the horns and realize the modulation is coming from your guitar amplifier rather than a Leslie at the side of the stage. Another testament to the richness of the Mini Vent is how is can make a cheap amp sound, well, expensive. My Vox Pathfinder 15 sounded rich, huge, and a whole lot like a real Leslie on a four-track demo. The Mini Vent even lent grandeur to the voice of a thrift store Casio keyboard I used for the same recording.

The Verdict
Folks will undoubtedly knock the cost of a pedal that, on the surface, looks like a one-trick pony. But if you love the sound of a rotary speaker and have already spent hundreds of dollars trying to fake it with other modulation devices, the 349 bucks won’t seem like much—especially when you fool most of your friends with a recorded sample. And as well as the Mini Vent is put together, we guess it’s an investment that will pay itself back though longevity too.

Watch the Review Demo: