The Neo Instruments Neo Micro Vent 122 is a compact rotary speaker simulator pedal that models the Leslie 122, the classic rotating-cabinet speaker associated with organ and guitar tones since the 1960s. It is a two-speed, mono pedal that packs the features of Neo's high-end Ventilator into a small stompbox enclosure, finished in black1.
The pedal was announced in November 2019 alongside its sibling, the white micro Vent 16, with both due out in January 2020 and prices still to be confirmed at announcement23.
What it simulates
A real Leslie 122 cabinet spins two rotors: a high-frequency horn and a low-frequency drum. The micro Vent 122's algorithm is derived from the Ventilator II and is modeled after that cabinet, complete with the classic miking technique built in. The algorithm places one virtual microphone on the horn and one on the drum rotor, and the distance of both mics can be varied with the DISTANCE pot4.
Guitar World described the 122 version as aiming for the more dramatic effect of a Leslie 122 rotary speaker, with deeper modulation and deeper movement than its sibling3.
The controls: speed, footswitch and Distance
The pedal keeps its control set small, but each control covers a lot of ground. Guitar.com's reviewer listed the controls as speed, distance, ramp and blend, plus a three-way toggle for the second speed and a latching or non-latching bypass footswitch5.
| Control | What it does |
|---|---|
| Speed 1 pot | Ranges continuously from Slow to Fast, including intermediate speeds4 |
| Speed 2, 3-way switch | Selects the standard speeds Slow, Fast or Stop4 |
| RAMP | Sets acceleration and deceleration between the two speeds4 |
| DISTANCE | Varies how far the two virtual mics sit from the horn and drum4 |
| Blend | Mixes effect and bypass signal5 |
| Footswitch | Silent switch with 5 operating modes for bypass and speed select4 |
The footswitch is flexible. It can switch the effect on and off or select between the two speeds, with modes for momentary or latching switching, and it can be set to select speeds exclusively while leaving the effect always on4. Special switch modes also allow flexible transitions such as Slow to Fast, Fast to Slow, Slow to Stop and Stop to Fast4. Holding the footswitch ramps the speed up1.
One limit worth knowing: only one of the two rotation speeds is fully adjustable. The second speed, activated by holding down the bypass footswitch, is fixed at fast, slow or stop5.
The Micro Vents are mono, with no drive option, unlike the larger Ventilator II which offers onboard overdrive and stereo outputs56.
Ventilator II technology and the Micro Vent 16
The micro Vent 122 uses Neo's Ventilator II technology to achieve the sound of the Leslie 1222. The Ventilator II, Neo's flagship, is modeled on the Leslie 122 with independent drum and horn circuits, onboard overdrive, adjustable fast/slow ramping and stereo outputs, running on a 32-bit SHARC DSP with complex modeling algorithms56. The micro Vent trims that feature set down to a board-friendly size: mono in and out, no drive, and a simplified control layout.
The two micro Vent versions differ in what they copy:
- micro Vent 122 (black): simulates a Leslie 122, the two-rotor cabinet with horn and drum, miked by two virtual microphones42.
- micro Vent 16 (white): simulates a Leslie 16, also known as the Fender Vibratone, a later and simpler rotary speaker with no horn, captured with a single virtual mic at variable distance45.
Neo describes the 16 as sounding less complex and dominant than the 122, positioning it for rhythm work and for giving lead tones a final touch4. Gearnews similarly characterized the 16 as simulating a Leslie with a 10-inch speaker into a single drum rotor, with a more subtle sound2. The controls on both pedals are the same2.
What reviewers said
Guitar.com reviewed both Micro Vents together in March 2020 and scored each 8/105. Writing about the pair, the reviewer's verdict on the 122 was:
"### Micro Vent 122: 8/10"
Richard Purvis, Guitar.com, March 20205
Gearnews, judging by the demo video, found the 122's overall sound very organic and tasty2. In a later comparison against the Boss RT-2 rotary ensemble, Guitar.com's reviewer found the Neo Micro Vents sound better but lose out on flexibility, citing their mono outputs, lack of overdrive and pricing7.
Videos
Mike Hermans
Alberto Barrero
Guitar Bonedo
Questions
What is the difference between the Neo Micro Vent 122 and Micro Vent 16?
The black Micro Vent 122 simulates a Leslie 122, the classic two-rotor cabinet with a horn and a drum, and aims for the more dramatic, deeper modulation. The white Micro Vent 16 simulates a Leslie 16, also known as the Fender Vibratone, a simpler single-drum rotor design. Neo says the 16 sounds less complex and dominant, suiting rhythm work.
Is the Neo Micro Vent 122 mono or stereo?
It is mono in and mono out. That is one of the trade-offs against the larger Ventilator II, which works in stereo and mono and has stereo inputs. Guitar.com's reviewer noted the Micro Vents are mono, with no drive option.
How do you ramp the speed on the Micro Vent 122?
A RAMP parameter sets the acceleration and deceleration between the two speeds, so the spin-up and spin-down can be as fast or slow as you like. Holding the footswitch also ramps the speed up, and the silent footswitch has five operating modes for bypass and speed selection.
What does the Distance knob do on the Micro Vent 122?
The algorithm simulates the classic miking technique with one mic on the horn and one on the drum rotor. The Distance knob varies how far those two virtual microphones sit from the cabinet, changing the character of the modulation the way mic placement does on a real Leslie.
When was the Neo Micro Vent 122 released?
Neo Instruments announced the Micro Vent 122 and Micro Vent 16 in November 2019, with availability from January 2020. Prices were still to be confirmed at the time of the announcement.
Sources (7)
- Best Rotary Pedals & Leslie Simulators In 2023: Compare Price And Features, Delicious Audio, 2023-02-13
- New Leslie rotary speaker effect pedals for guitar: Neo Micro Vent 122 and 16 pedals, gearnews.com, 2019-11-27
- Neo Instruments will make your tone spin with its micro Vent 122 and micro Vent 16 rotary effects pedals, Guitar World, 2019-11-26
- micro Vent, neo-instruments.com
- Review: Neo Instruments Micro Vent 122 & 16, Guitar.com, 2020-03-11
- Ventilator II, neo-instruments.com
- Boss RT-2 Rotary Ensemble review: doesn’t compromise on features, Guitar.com, 2025-10-01
