Begrippenlijst
De AV- en IT-begrippenlijst
Heldere uitleg van de begrippen die in elke installatie voorbijkomen, van enkellijnschema tot Dante. Geschreven door het team achter Avitly.
A
Acoustic echo cancellation(AEC)
Processing that stops far-end callers hearing their own voice echoed back from a room's microphones and speakers.
In a conference room, the microphones pick up the far-end audio coming from the room speakers and send it back, so callers hear themselves delayed. Acoustic echo cancellation models and subtracts that path in real time.
AEC is a core job of the room DSP and is what makes a hands-free call sound natural. Poor microphone and speaker placement makes its job harder, which is why the acoustic layout matters as much as the processing.
As-built documentation
The final set of drawings and schedules updated to reflect what was actually installed, not just what was designed.
As-built documentation is the design corrected to reality: the diagrams, rack elevations, and cable schedules updated to match what the crew actually installed after the inevitable on-site changes.
It is what makes a system serviceable years later, and often a contractual deliverable. As-builts are far cheaper to produce when the design lived in one connected tool than when they must be reconstructed from memory.
AV control system
The programmable layer, touch panels, processors, and logic, that ties a room's AV, lighting, and shades into simple actions.
A control system turns a room full of separate devices into buttons a user understands: start meeting, present, lights down. A central processor talks to each device over IP, RS-232, or contact closures and runs the logic behind each action.
The hardware is only half of it; the programming is the deliverable. Clear documentation of what each button does keeps a system supportable when the original programmer has moved on.
AV over IP(AVoIP)
Distributing audio and video as data over a standard network switch instead of through a dedicated AV matrix.
AV over IP encodes video and audio into network packets and moves them over ordinary Ethernet, so a switch replaces the fixed input-by-output matrix. Scaling means adding endpoints and switch ports, not buying a bigger matrix chassis.
It shifts AV design onto the network: bandwidth, switch selection, multicast, and VLANs decide whether it works. Done well, routing any source to any display becomes a configuration change rather than a re-wire.
B
Balun
A small adapter that lets a signal designed for one cable type run over another, typically video over twisted-pair.
A balun converts between cable types so a signal can travel on infrastructure it was not designed for, most often sending video and control over structured Category cabling instead of dedicated coax or HDMI.
Baluns come in pairs, one at each end, and extend reach cheaply. Matching the pair to the signal and respecting its distance limit keeps an extended run clean.
Beamforming microphone
A microphone array that electronically steers its pickup toward talkers and away from noise.
A beamforming microphone uses many small capsules and processing to focus, or steer, its sensitivity toward whoever is speaking, rejecting HVAC hum and reflections. One ceiling array can cover a table that once needed several mics.
It simplifies the visible install but pushes complexity into tuning and room acoustics. Coverage mapping at design time is what delivers even pickup across every seat.
Bill of materials(BOM)
The complete, itemised list of every product a job needs: devices, mounts, cable, connectors, and consumables, with quantities.
A bill of materials (BOM) is the parts list for an installation. A good BOM is reconciled: every device drawn on the plan appears once, quantities match what the racks and cabling actually require, and nothing quoted is missing from the design.
The BOM is where margin leaks. A drawn-but-unquoted item is money you spend and never bill; a quoted-but-unplaced item is a line your client questions. Reconciling it against the plan closes both gaps.
C
Cable schedule
A table listing every cable in a job: its label, type, endpoints, and length, used for pulling, terminating, and testing.
A cable schedule enumerates every run in the system: a unique label, the cable type, both endpoints, and the length. Installers pull and terminate from it; commissioning engineers test against it.
Length matters for cost and for signal integrity. A true length includes the horizontal run, slack at both ends, and the vertical drop a top-down plan cannot show, all of which a flat estimate off a 2D drawing misses.
Voltage drop calculatorCategory cable(Cat5e / Cat6)
The twisted-pair cabling standard, Cat5e, Cat6, Cat6a, that carries network data and much modern AV and control.
Category cable is the workhorse twisted-pair used for Ethernet and, increasingly, for AV over IP, HDBaseT, PoE, and control. Each grade (Cat5e, Cat6, Cat6a) supports higher bandwidth over defined distances.
Choosing the right grade, and respecting the 100-metre channel limit, is a design decision, not a site improvisation. Plenum-rated versions are required where cable runs through air-handling spaces.
Commissioning
The structured process of testing, tuning, and verifying a finished system against its design before handover.
Commissioning is the final proof that a system does what was specified: every source reaches every display, audio is tuned, control works, and levels are set. It turns an installed system into an accepted one.
A commissioning checklist tied to the design catches the gaps a quick look misses, and produces the record a client, or an as-built, relies on later.
Constant-voltage speakers(70V / 100V)
A distributed-audio scheme that runs many speakers on long lines at high voltage, common for paging and background music.
Constant-voltage systems (70V in North America, 100V in Europe) let dozens of speakers share a single amplifier over long cable runs. Each speaker taps off a set number of watts via a transformer, so total load is a simple sum.
This is the standard for background music and paging across large or spread-out sites. The design check is the wattage budget: the tapped power of every speaker must stay within the amplifier's rating.
Speaker impedance calculator
D
Dante
A protocol for carrying multi-channel digital audio over standard IP networks with tight synchronisation and low latency.
Dante moves many channels of uncompressed digital audio over ordinary Ethernet, keeping devices sample-accurately synchronised. It has become the default for networked audio in conferencing, live sound, and large venues.
Because it rides on standard networking, a Dante design is as much an IT task as an AV one: VLANs, switch selection, and QoS all matter. Get the network right and audio routing becomes software, not re-cabling.
Digital signage
Networked displays showing managed content, menus, wayfinding, advertising, updated centrally across one or many sites.
Digital signage puts screens under central control: a content system schedules and pushes what each display shows, from a single lobby screen to a retail estate of hundreds. Content, network, and hardware all have to line up.
As a rollout, signage rewards standardisation, one screen and mount design repeated per site, so pricing, spares, and support stay simple across the whole estate.
Digital signal processor(DSP)
A programmable audio device that mixes, equalises, and conditions signals, the brain of a conferencing or venue sound system.
A DSP handles the audio maths in a room: mixing microphones, equalisation, gain, echo cancellation, and routing. In a conference space it is what makes far-end callers hear a clean, single voice instead of a boomy room.
Because it is programmed rather than wired, a DSP design lives in its configuration. Documenting inputs, outputs, and processing blocks keeps a system serviceable long after commissioning.
DMX512
The standard control protocol for stage and architectural lighting, addressing many fixtures over one data chain.
DMX512 sends lighting control over a daisy-chained data line, giving each fixture or channel an address within a 512-slot universe. A console or controller sets levels and effects across the chain.
Where AV and lighting meet, in venues, houses of worship, and events, DMX is often integrated into the control system so scenes trigger lighting and AV together.
E
EDID
The data a display sends back to a source describing the resolutions, refresh rates, and audio formats it accepts.
Extended Display Identification Data (EDID) is how a screen tells a source what it can handle. The source reads it and picks a compatible format. When EDID is wrong or blocked, a source may output a resolution the display cannot show.
In switched and extended systems, EDID management, forcing or emulating a known-good profile, is often what makes a stubborn source-to-display link behave.
F
Fiber optic
Cabling that carries signals as light, used where distance or bandwidth exceeds what copper can deliver.
Fiber-optic cable sends data as pulses of light down a glass or plastic core, covering far greater distances than copper and immune to electrical interference. It is the answer when a run is too long for Category cable or must cross a noisy environment.
In AV it links buildings, extends high-bandwidth video, and future-proofs backbones. The trade-off is cost and termination skill, so it is specified where its reach genuinely earns its place.
H
HDBaseT
A standard for sending uncompressed HD/4K video, audio, control, and power over a single twisted-pair cable up to 100 m.
HDBaseT carries video, audio, control, Ethernet, and power over one Category cable, extending an HDMI-class signal far beyond HDMI's practical reach, typically up to 100 metres.
It is a workhorse for getting a source to a distant display without a rack of extenders. Cable quality and length limits are the usual failure points, so the run length in your cable schedule is not just a cost input, it is a go/no-go check.
HDCP
A copy-protection layer on HDMI and DisplayPort that encrypts protected content between source and display.
High-bandwidth Digital Content Protection (HDCP) encrypts protected video, streaming services, Blu-ray, so it only plays on authorised displays. Every device in the chain must support the same HDCP version or the picture drops to black or a warning.
It is a common cause of a signal that works on the bench but fails in a matrix or over a long extender. Checking HDCP compatibility across the whole path avoids a mystery no-signal on install day.
K
KVM
Technology that extends or switches a computer's keyboard, video, and mouse to a remote location or between machines.
KVM (keyboard, video, mouse) lets an operator control one or many computers from a distance, or switch between machines at one desk, keeping the noisy, hot hardware in a secure rack away from the workspace.
It is common in control rooms, broadcast, and trading floors. Modern KVM often runs over IP, sharing the same networked-AV design considerations of bandwidth and latency.
L
Latency
The delay between a signal entering a system and leaving it, critical for live audio, video, and lip-sync.
Latency is lag: the time a frame or sample takes to pass through encoders, processors, and the network. Small amounts are invisible; enough of it makes audio drift from video or a live talker echo on a screen behind them.
Every processing stage and network hop adds a little. In live production and AV over IP, budgeting latency across the chain keeps sound and picture locked together.
Line array
A column of loudspeakers arranged to project sound evenly over distance, used in larger rooms and venues.
A line array stacks or hangs multiple speaker elements in a vertical column so their output combines into a controlled, far-reaching pattern, delivering more even coverage front-to-back than a single box.
Design is about coverage geometry: splay angles, height, and aim so every seat gets consistent level and intelligibility. Modelling it before rigging avoids dead spots and hot rows.
Lumens
The measure of a projector's light output, which, against ambient light and screen size, decides whether an image looks bright.
Lumens quantify how much visible light a projector emits. More lumens means a brighter image, but the right number depends on room light, screen size, and gain, a dim room needs far fewer than a sunlit boardroom.
Specifying lumens without accounting for ambient light is a common miss that leaves a washed-out picture. Tying brightness to the actual room is part of a defensible design.
M
Matrix switcher
A device that routes any of several AV inputs to any of several outputs, the switchboard at the heart of a fixed AV system.
A matrix switcher connects multiple sources to multiple displays and lets any input reach any output. It is described by its size, an 8x8 routes eight sources to eight screens, and by the signal types and resolutions it passes.
Traditional matrices are fixed hardware; AV-over-IP achieves the same routing on a network switch. Which approach fits depends on scale, distance, and how often the routing must change.
N
NDI
A protocol for sending high-quality, low-latency video between devices over a standard IP network, common in live production.
Network Device Interface (NDI) moves broadcast-quality video over ordinary Ethernet with low latency, letting cameras, computers, and switchers share sources across a network instead of via SDI cabling.
It is popular in live events, houses of worship, and studios because any NDI source is discoverable on the network. As with all AV over IP, the switch and bandwidth design decide whether it holds up under load.
P
Patch panel
A panel of ports that terminates permanent cable runs, so devices connect with short, swappable patch leads.
A patch panel is where the fixed cabling of a building lands. Instead of running a permanent cable to each device, runs terminate at the panel and a short patch lead makes the final connection, so changes happen at the rack, not in the walls.
Patch panels are the backbone of structured cabling and keep a rack maintainable. A labelled panel tied to the cable schedule turns a future move-add-change into minutes of work.
Power over Ethernet(PoE)
Delivering electrical power and data to a device over the same Ethernet cable, removing the need for a local outlet.
Power over Ethernet powers cameras, access points, phones, and displays through the data cable itself, so a device needs one run instead of a cable plus a nearby socket. PoE standards define how much wattage a port can supply.
The catch is budget and distance: the switch has a total power budget, and voltage drop over a long run can starve a device. Both belong in the design, not on the punch list.
Voltage drop calculatorPunch list
The list of outstanding defects and unfinished items that must be resolved before a job is signed off.
A punch list, or snag list, records what is left: a loose panel, a mislabelled cable, a display that flickers. It is walked near the end of a job and cleared item by item before final acceptance and payment.
A short punch list is a sign of a clean install and clear documentation. Many of its items trace back to gaps that a reconciled design would have flagged before the crew arrived.
Q
Quality of Service(QoS)
Network settings that prioritise time-sensitive traffic, so audio and video are not disrupted by other data.
Quality of Service tags and prioritises packets on a network so latency-sensitive AV, Dante audio, video streams, control, gets through ahead of bulk data like file transfers or backups.
Without QoS, a large download can glitch a live stream sharing the same switch. Configuring it correctly is what makes converged AV and IT networks reliable.
R
Rack elevation
A front-view drawing of an equipment rack showing every device in its rack-unit position, top to bottom.
A rack elevation lays out a rack as the installer will build it: each device in its rack-unit (RU) slot, with blanks, shelves, and power in place. It doubles as a build guide on site and a professional deliverable for the client.
Accurate elevations catch problems early, running out of RU space, overloading a circuit, forgetting ventilation, before anything is ordered or mounted.
Rack unit(U / RU)
The standard vertical measure of rack-mount equipment and rack space: one U equals 1.75 inches (44.45 mm).
A rack unit (U or RU) is the module every 19-inch rack and rack-mount device is sized in. A 2U amplifier occupies two units; a 42U rack has that many slots. It is the currency of a rack elevation.
Counting U early, plus space for cable management, ventilation, and future growth, avoids the classic mistake of a design that will not physically fit the rack once power and blanking are added.
RS-232
A long-standing serial protocol for sending commands to AV devices such as displays, projectors, and switchers.
RS-232 is a simple, robust serial standard that control systems use to send commands, power on, switch input, set volume, to AV hardware. Despite its age it remains ubiquitous because it is dependable and well documented.
Each device has its own command set, so control programming means mapping those strings to user actions. Many devices now offer IP control alongside RS-232, but the serial port is still the reliable fallback.
S
Scope of work(SOW)
The document defining exactly what an integrator will deliver: systems, spaces, responsibilities, and what is explicitly excluded.
A scope of work (SOW) states what is being delivered and, just as importantly, what is not: which rooms, which systems, who provides the network, who patches the wall. It is the reference that settles change-order disputes.
A precise SOW protects margin. Tied to a clear design and a reconciled bill of materials, it leaves little room for the assumptions that turn a profitable job into an unpaid one.
SDI
A professional standard for sending uncompressed video over coaxial cable, standard in broadcast and live production.
Serial Digital Interface (SDI) carries uncompressed video, and embedded audio, over coax with locking BNC connectors, tolerating long runs far better than HDMI. Variants (HD-SDI, 3G, 12G) step up to higher resolutions.
Its ruggedness and reach make it the default in broadcast and staging. Many modern workflows now bridge SDI and IP-based transport such as NDI within the same facility.
Signal flow diagram
A diagram tracing how audio, video, and control signals move through a system, from source to destination, stage by stage.
A signal flow diagram follows each signal, an HDMI feed, a Dante audio stream, an RS-232 control line, from where it originates to where it lands, through every switcher, processor, and amplifier in between.
Where a single-line diagram summarises, a signal flow diagram is where you verify that a source can actually reach its display in a compatible format. Mismatched connectors or signal types show up here first.
Single-line diagram(SLD)
A simplified drawing that shows every device in an AV system and the one signal path between each, without drawing every conductor.
A single-line diagram (SLD), also called a one-line, represents an audiovisual system as boxes for each device connected by single lines that stand for a signal run. It answers what connects to what and in which direction, without the clutter of drawing every pin or conductor.
Integrators use the SLD as the master reference for a job: it drives the bill of materials, the cable schedule, and the rack layout. Keep it accurate and every downstream document stays honest.
Site survey
The on-site assessment of a space that grounds an AV design in real dimensions, structure, and constraints.
A site survey is the visit that turns assumptions into facts: real measurements, wall construction, ceiling access, power locations, sightlines, and existing infrastructure. It is where a design stops being a guess.
Surveying before designing avoids the expensive discovery, on install day, that a run is longer, a wall is concrete, or a projector has nowhere to mount. The plan should reflect what the survey found.
Speaker impedance
The AC resistance a loudspeaker presents to an amplifier, measured in ohms, which sets how many speakers a channel can safely drive.
Impedance, in ohms, determines the load a speaker places on an amplifier. Wire speakers in series or parallel and the combined impedance changes, which decides how many a single amplifier channel can drive before it overheats or clips.
Get the total load wrong and you either damage the amplifier or starve the speakers. This is why distributed audio designs are checked at the impedance level before a single cable is pulled.
Speaker impedance calculatorStructured cabling
A standardised cabling system organised into subsystems, so any device can connect predictably through patch panels and known runs.
Structured cabling is the disciplined alternative to point-to-point wiring: standardised media, patch panels, and labelled runs organised into subsystems. It makes a building's infrastructure predictable to install, test, and change.
For AV/IT integrators it is the backbone that carries Dante audio, IP video, and control across a site. A clean structured-cabling design keeps the cable schedule and rack layout maintainable years after handover.
Subnet
A subdivision of an IP network that groups devices into a defined address range for organisation and routing.
A subnet carves an IP network into smaller blocks, each a contiguous range of addresses defined by a mask. Devices in the same subnet talk directly; crossing subnets goes through a router.
Planning subnets, one for AV, one for control, one for corporate, keeps a networked system organised, secure, and easy to troubleshoot. The addressing belongs in the project documentation.
IP subnet calculator
T
Throw ratio
A projector's distance-to-image-width ratio, used to work out how far from the screen it must sit for a given image size.
Throw ratio expresses how big an image a projector makes from a given distance, a 1.5:1 ratio fills a 2-metre-wide screen from 3 metres away. It is the number that decides where a projector can physically mount.
Checking throw ratio against the room, and any obstructions, on the plan prevents ordering a projector that cannot make the required image from the only place it can be mounted.
V
Video wall
An array of tiled displays or LED panels driven as one large, seamless canvas.
A video wall combines multiple screens, LCD panels with thin bezels or fine-pitch LED tiles, into a single large image, or several zones, driven by a processor that splits and scales the content.
Design turns on pixel pitch, viewing distance, bezel width, mounting flatness, and heat. Getting those right on the plan is what separates a crisp wall from one with visible seams and hot spots.
VLAN
A logical network that segments traffic on shared switches, used to isolate AV, control, and corporate data.
A Virtual LAN partitions one physical network into separate logical ones, so AV-over-IP video, control, and office traffic each ride their own segment on the same switches without seeing each other.
Segmentation protects bandwidth-heavy AV streams from congestion and keeps devices secure and discoverable in the right scope. It is a foundational decision in any networked AV design.
Voltage drop
The loss of voltage along a cable run, which grows with length and current and can leave a device under-powered.
Every conductor has resistance, so voltage falls along its length. Over a long run, or at high current, that drop can leave a powered device, a PoE camera, a display, a remote amplifier, below the voltage it needs to work reliably.
Designers counter it with thicker conductors, shorter runs, or higher supply voltages. Checking voltage drop at design time avoids the maddening on-site fault of a device that powers up but behaves erratically.
Voltage drop calculator
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