The Neo Instruments Ventilator is a digital rotary speaker emulation pedal: a unit that recreates the sound of a Leslie rotating speaker cabinet, the kind paired with Hammond organs and later adopted by guitarists, in a box that sits on a desktop or pedalboard instead of a floor1. Specifically, it emulates the Leslie Model 122, one of the most famous cabinets in the Leslie lineup12. Delicious Audio's buying guide calls it "a desktop-style pedal that emulates the Leslie 122"2.
The original Ventilator has since been joined by the Ventilator II, which the maker describes as using complex modeling algorithms for a precise replication of Leslie 122 rotary effects, picked up with three virtual microphones3. Guitar.com describes the Ventilator II as "modelled on the Leslie 122, complete with independent drum and horn circuits plus onboard overdrive, adjustable fast/slow ramping and stereo outputs"4. Neo Instruments also makes smaller versions, the mini VENT II and the micro Vent 122 and micro Vent 16, for players short on board space.
What it does
A Leslie cabinet produces its sound by spinning a bass rotor (the drum) and a treble rotor (the horn) at two speeds, with a characteristic ramp between them. The Ventilator models this electronically. MusicRadar describes it as "a digital emulation of the Leslie Model 122" and "a foot pedal designed to emulate the sound of a Leslie rotating speaker cabinet"1. The Ventilator II runs its digital signal processing at 48 kHz with 24-bit conversion in both directions, and the maker states that no compromise was made in the design of the analog section around it3.
The unit works in stereo and mono; the maker's page for the Ventilator II says it "not only sounds great in stereo, but also in mono," and gives it stereo inputs as well as outputs3. Premier Guitar's review of the original notes stereo outputs on the rear panel5.
The controls
MusicRadar's review walks through the front panel of the original Ventilator1:
| Control | What it does |
|---|---|
| Speed | Governs the rate of the virtual rotors' movement |
| Acceleration | Controls the rate at which the rotors come up to speed when switching between slow and fast modes |
| Balance | Varies the relative levels of the low and high signals, a basic but effective tone control |
| Distance | Adjusts virtual mic placement; at lower settings the amplitude modulation effect is more pronounced, decreasing at greater distances |
| Drive | Recreates the effect of pushing the 122's amp hard, a basic tube overdrive sound |
Premier Guitar describes the Balance knob in similar terms: it adjusts the relative volume of the virtual lower rotor, which handles bass tones, and the rotating horn, which produces the trebler tones5. The Acceleration control is the one that captures a big part of what makes a Leslie feel real to players: the lag as the rotors spin up and down between slow and fast, rather than an instant change.
Key and Guitar modes
A push-button switch on the back toggles between Keyboard and Guitar modes1. The two modes shape the unit differently depending on what you feed it:
- Keyboard (Key) mode emulates the highly colored tone of the original 122 cabinet1. Premier Guitar says that switched to Key, it replicates the frequency response of a Leslie 1225.
- Guitar (Git) mode offers the modulation effect without coloring the signal1. Premier Guitar describes the 6-string-optimized Git mode as more linear, with less signal coloration5.
For a guitarist comparing rotary options, that mode switch is the Ventilator's practical answer to a real problem: a Leslie's frequency response was voiced for an organ, and a straight emulation of it can darken or reshape a guitar tone more than intended. Git mode keeps the swirl and drops most of the reshaping. Players looking at other rotary pedals can compare it against units like the Strymon Lex, the Boss RT-20 Rotary Ensemble, the Electro-Harmonix Lester G Deluxe, and the Tech 21 RotoChoir, all covered elsewhere in our speaker simulation section51.
The Ventilator II and the smaller versions
The Ventilator II adds a connection for a remote footswitch, halfmoon switch, or expression pedal3, something the original lacks: MusicRadar's reviewers wrote that "we'd have liked an expression pedal input for speed control" on the first-generation unit1. Halfmoon switches are the speed controls organists mount under a Hammond, so that connection points the II squarely at keyboard players as well as guitarists.
The original's size was a recurring theme. Gearnews wrote that "the Ventilator pedal sounds amazing but it's big and will take up a fair amount if space on your pedalboard"6, around the time Neo Instruments announced the two smaller Micro Vent pedals6. Guitar.com reviewed the Micro Vent 122 and the Micro Vent 16, describing them as board-friendly versions of the Ventilator4. Premier Guitar, for its part, pushed back on the size concern for some uses, noting "the compact dimensions of the 2-pound, 7-ounce Ventilator alone make it worth a look" next to hauling a real Leslie5.
What reviewers said
Reviews across the press were consistent about the emulation quality:
"One of the most realistic rotary speaker emulations we've seen - the next best thing to a real Leslie1."
MusicRadar's overall verdict1
"the quality of its emulation is truly exceptional, with a depth of realism that few can match"2
Delicious Audio's rotary pedal buying guide, which also notes that "Neo Instruments was among the pioneers in this field, blowing everyone away with the Ventilator"2
Premier Guitar's review praised the build as well as the sound: "The enclosure is all aluminum and thoughtfully designed with recessed knobs"5. The criticisms that appear in the press are practical rather than sonic: the size on a pedalboard6, and the absence of an expression pedal input on the original1, the latter addressed in the Ventilator II3.
Videos
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Pete Thorn
Jim Alfredson
Questions
Is the Neo Instruments Ventilator analog or digital?
It is digital. MusicRadar describes the Ventilator as a digital emulation of the Leslie Model 122, and the maker's page for the Ventilator II lists 48 kHz, 24-bit analog-to-digital and digital-to-analog conversion, with an analog section in the signal path as well.
Does the Ventilator have an expression pedal input?
The original Ventilator does not. MusicRadar's reviewers noted they would have liked an expression pedal input for speed control. The Ventilator II adds a connection for a remote footswitch, halfmoon switch, or expression pedal.
Does the Ventilator have stereo outputs?
Yes. Premier Guitar's review notes stereo outputs on the rear panel of the original Ventilator. The Ventilator II works in both stereo and mono and has stereo inputs as well.
Where is the Neo Instruments Ventilator made?
Germany. Premier Guitar's review describes the Ventilator as German-made, in an all-aluminum enclosure with recessed knobs, weighing 2 pounds 7 ounces.
Can you use the Ventilator with a guitar as well as a keyboard?
Yes. A push-button switch on the back toggles between Keyboard and Guitar modes. Key mode replicates the frequency response of a Leslie 122, while Git mode is more linear and colors the signal less, which suits guitar.
Sources (6)
- Neo Instruments Ventilator review, MusicRadar, 2012-01-30
- Best Rotary Pedals & Leslie Simulators In 2023: Compare Price And Features, Delicious Audio, 2023-02-13
- Ventilator II, neo-instruments.com
- Review: Neo Instruments Micro Vent 122 & 16, Guitar.com, 2020-03-11
- Neo Instruments Ventilator Rotary Pedal Review, Premier Guitar, 2011-06-14
- New Leslie rotary speaker effect pedals for guitar: Neo Micro Vent 122 and 16 pedals, gearnews.com, 2019-11-27
