What is a musical fountain?

A musical fountain is a fountain system whose water jets and lights move in sync with a piece of music. Each jet's height is varied in real time through a pump and VFD to match the song's rhythm and sections, so the water appears to dance to the music.

What is a dry-deck (kuru havuz) fountain?

A dry-deck fountain is a fountain whose jets are flush with a walkable surface, with no visible basin. Because the deck stays walkable when the jets are off, it is the most common municipal format in Turkish city squares; in Turkish it is called kuru havuz.

What is a VFD and why is it needed for a musical fountain?

A VFD (variable-frequency drive) adjusts a pump motor's frequency, and therefore its speed and the jet height, in real time. A fountain can only follow music if its pumps can be driven by a VFD; where that holds, an existing pool can be made to dance by adding only the control boards, without changing the plumbing.

What is the difference between a sound-reactive fountain and authored choreography?

A sound-reactive system merely maps instantaneous loudness to jet height; because it does not read the music ahead of time, it reacts a beat late and cannot anticipate. Authored choreography analyzes the whole song in advance and prepares the jets before the beat, so motion lands on time and follows the music's structure.

What is a digital twin?

A digital twin is a physics-based software copy of the real pool. The choreography produced by the AI is validated on this twin in 3D before going on site, so you can preview in the browser how the show will look on the actual fountain before installation.

Musical fountain & AI choreography glossary

This glossary gathers the core terms of the musical-fountain world under four headings: general concepts, hardware, AI and show, and installation and operation. Each definition is short and self-contained, giving municipalities writing technical specifications, designers and operators a shared vocabulary.

General terms

Musical fountain: A musical fountain is a fountain system whose water jets and lights move in sync with a piece of music; pumps, VFDs and a control board vary each jet's height and rhythm to match the song.
Dancing fountain: Dancing fountain is a common name for a musical fountain; because the water columns rise and fall with the music, the jets appear to dance. Technically it describes the same system as a musical fountain.
Water-light show: A water-light show is a choreographed performance combining water jets with RGB lighting set to music; the color layer engages after dark, while motion leads during daytime.
Dry-deck fountain (kuru havuz): A dry-deck (plaza) fountain has jets flush with a walkable surface and no visible basin; it is the dominant municipal format in Turkish city squares. Its Turkish name is kuru havuz.
Ornamental pool (süs havuzu): An ornamental pool is a decorative pool with a visible water surface; it can be made to dance by adding musical-fountain hardware.
Jet: A jet is a single column of water shot up from a nozzle; each jet can be controlled independently in height and timing by its own pump and driver.
Nozzle (lüle): A nozzle is the outlet through which water leaves into the air; its shape determines the jet's form (straight column, fan, foam, and so on).
Fountain choreography: Fountain choreography is the planned sequence of jet heights, light colors and timings across a piece of music; good choreography anticipates the song's sections and accents.
Retrofit: A retrofit makes an existing fountain music-driven using only Arcus control boards and AI, without rebuilding it; the only requirement is that the pumps can be driven by a VFD. The plumbing and basin are not replaced.

Hardware

Pump: A pump is the unit that forces water up to the nozzle under pressure; as its speed changes, so does the jet's height. In a musical fountain each pump is controlled quickly and steplessly through a VFD.
VFD (variable-frequency drive): A VFD changes a pump motor's frequency to adjust its speed, and therefore the jet height, in real time. For a fountain to follow music, its pumps must be drivable by a VFD.
Main controller: The Main is a pool's brain; it runs the show, holds the timer and manages every end-unit over the buffer lines. It is the permanent, authoritative source of the pool's settings.
End-unit: An end-unit is the node corresponding to a single jet; it contains a motor+pump driver and/or an RGB light. An example 150-unit system is made of 75 Driver and 75 RGB end-units.
Driver: A Driver is the board that runs an end-unit's pump motor through a VFD; it applies that jet's height and timing according to commands from the Main.
RGB: An RGB is a red-green-blue LED unit that lights a jet; the color layer engages after dark, while the motors always run (this rule can be disabled for indoor use).
Buffer: A buffer is a line that connects end-units to the Main; each buffer carries at most 30 end-units. A 150-unit system is spread across roughly 10 buffers.
Raspberry Pi gateway: A Raspberry Pi gateway is an optional unit that adds internet, audio playback and remote access; it does not replace the Main but works alongside it.
Modbus: Modbus is a common communication protocol for VFDs and industrial devices; the control board can send speed commands to the pump drivers over it.
RS485: RS485 is a serial data link that works reliably over long distances and in noisy environments; the buffer lines and pump communication run over this physical layer.
DMX: DMX is a standard control protocol in stage lighting and effects; in traditional fountain programming, separate DMX commands are written by hand for every moment. A 3-minute show can require 1,500-6,000 commands.
BLE (Bluetooth Low Energy): BLE is a low-power Bluetooth link that lets a phone connect wirelessly to the Main at close range; it is used for on-site control without internet.

AI and show

AI show composer: The AI show composer is the Arcus component that analyzes a whole song offline (beats, sections, build-ups, drops, energy) and builds an anticipatory choreography from water/light animations. It produces a show in minutes without a specialist.
Authored choreography: Authored choreography is a planned show prepared with foreknowledge of the music's coming moments; because jet preparation starts before the beat, the motion lands exactly on time. This is its core difference from sound-reactive systems.
Sound-reactive: A sound-reactive system merely maps instantaneous loudness to jet height; because it does not read the music ahead, it reacts a beat late and cannot anticipate. Arcus produces authored choreography instead.
Cue: A cue is a single timed instruction in the choreography; at a specific moment it assigns height, motion or color to specific jets. A show is a sequence of hundreds of cues.
Animation palette: The animation palette is the set of ready water/light motions from which choreography is built (for example wave, sway, scatter). The composer selects from it to build the sequence to the music.
Digital twin: A digital twin is a physics-based software copy of the real pool; the produced choreography is validated on this twin before going on site, so it is watched in the browser exactly as it will appear in the field.
Simulator (3D): The simulator is the tool that shows the digital twin in the browser in real-time 3D; it animates water physics, jet heights and light to preview the show.
Beat: A beat is the basic rhythmic unit of music; the AI extracts the song's beat grid and locks jet motions onto it.
Drop / section: A section is a structural part of a song such as chorus, bridge or build-up; a drop is the moment of peak energy. The composer builds choreography that anticipates these moments.
Prespin (offset): Prespin is spinning the pump up slightly before the target moment; because the water column takes time to rise, the pump is started early so the jet reaches the right height exactly on the beat. It is compensation for a physical delay, not an audio-sync setting.

Installation and operation

Technical specification (teknik şartname): A technical specification is the document defining the technical requirements a fountain project must meet; municipalities and institutional buyers run the tender through it.
Project (proje): The project is the design/implementation file showing the fountain's layout, jet count, hardware and show arrangement; with the technical specification it forms the basis of public procurement.
Municipal procurement: Municipal procurement is the process by which public fountains are purchased through a technical specification and project; the dry-deck fountain is the most-requested format in city squares.
Timer / trigger: A timer makes shows start automatically at set times of day; a trigger is a rule that starts a show on an event or condition. Both are held on the Main.
Design studio: The design studio is the web interface where shows are built, edited and previewed with the simulator; installation and configuration are done here.
OTA (over-the-air update): OTA is updating the boards' firmware without physical access; new features and fixes reach a fountain in the field this way.
Quote: A quote is Arcus's pricing model; the system is configured online and a quote is issued based on the configuration instead of a fixed list price.
Phone app (operator): The phone app is for day-to-day operation after installation; the operator selects and runs a show. Hardware configuration and commissioning are done on the web.