In this guide: Audio first · Sizing by room · Microphones · Open mics · Loudspeakers · Hybrid and AEC · Display and sources · Cabling · Control · Acoustics · Accessibility · Commissioning · Mistakes · Picks · FAQ

Audio first, always

Most meeting room briefs arrive as a screen size, because the screen is the visible part of the budget. That order is the best predictor of a room nobody books. A meeting is speech: if the far end has to ask for a sentence twice, the meeting has failed.

Intelligibility depends on how much direct sound reaches the microphone compared with reflected sound, how much steady background noise the room has, and how evenly the reproduced sound reaches listeners. None of that improves by spending more on the panel. Settle microphones, loudspeakers and processing first, then buy the largest display the budget still supports.

Sizing by room and headcount

The expensive jump is from a room where one all-in-one device can hear everybody to a room where it cannot, because that is where discrete microphones, a processor and cable infrastructure arrive.

A boardroom is where the design work starts, because talkers are three to eight metres from any single device. A training room then adds reinforcement, since the presenter must be heard in the room as well as at the far end. A divisible room needs zones that route independently, and zoning is expensive to correct later.

Microphone options and their trade-offs

Every microphone decision trades closeness to the talker against hardware on the table.

Ceiling arrays

Beamforming arrays steer a pickup lobe towards whoever is talking, so nothing sits on the table and nothing gets unplugged. They are network devices, usually powered over Ethernet with audio on Dante or AVB. The cost of that tidiness is distance: an array is two to three metres from a mouth where a gooseneck is thirty centimetres, so it hears proportionally more room and ventilation noise.

Table boundary microphones

Boundary microphones use the table as an acoustic boundary, which puts them much closer to talkers. Cardioid, bidirectional and omnidirectional versions cover one seat, two facing seats or a small cluster, and versions with a mute switch and LED give visible control. Cables come up through the table.

Gooseneck microphones

A gooseneck gives the best intelligibility per talker of anything short of a headset, because the capsule sits in front of the mouth with a tight pattern rejecting everything else. It is the standard for council chambers and formal boardrooms, and the visible mute switch matters: people trust a microphone they can see is off. One per seat is the expensive ideal and drives the open microphone count up fast, so sharing between two adjacent seats is common. Our gooseneck guide covers lengths and patterns.

Wireless for training rooms

Trainers walk and turn away from fixed microphones. A lavalier gives hands-free consistency; a handheld suits questions from the floor. Both need charging discipline, so a dock in the rack earns its premium. UK wireless use is regulated and the band determines whether you need a licence: see our Channel 38 licensing guide.

The open microphone problem

Every open microphone contributes not just its talker but the whole room: ventilation, fans, reverberation, traffic. The working rule in automatic mixer design is to attenuate by 3 dB for every doubling of the number of open microphones. Put the other way round, eight open microphones deliver roughly 9 dB more background noise and reverberation than one, which sounds about twice as loud, and it eats into the gain available before feedback.

The fix is an automatic microphone mixer, now built into conferencing DSPs rather than bought separately. Automixers either gate microphones nobody is talking into, or continuously share gain so the effective open count stays low.

Loudspeakers: distributed ceiling or a stereo pair

In a small room, two compact cabinets flanking the screen are simple and put the sound where people are already looking. Stereo separation is irrelevant for speech. The limitation is coverage: seats nearest the screen get much more level than seats at the far end of the table.

Beyond five or six metres, a grid of ceiling speakers at modest level gives every seat a similar level from a source above it. Because each listener is close to a speaker the system needs far less gain, which reduces feedback risk and gives echo cancellation an easier job. Commercial ceiling speakers come in low impedance and 100 V line versions: 100 V line suits several speakers on a long run from a rack, low impedance a handful near the amplifier. Our background audio guide covers 100 V line distribution.

Either way, the geometry between loudspeaker and microphone decides whether the room works. A ceiling speaker directly above a table microphone delivers a loud early echo the processing then has to fight. Offset speakers from microphone positions and keep the level at each microphone low; our feedback guide applies as much to a lectern as to a stage.

Hybrid meetings: the USB path and echo cancellation

A hybrid room has to get audio into and out of a conferencing platform, and in practice that happens over USB. The room processor, or the all-in-one bar, presents itself to the connected computer as a standard USB audio device: one microphone input and one loudspeaker output. Teams or Zoom sees one device to select, exactly as it would a headset, and knows nothing about the sixteen microphones and eight ceiling speakers behind it. Either leave a dedicated appliance signed into the platform, or run meetings from a visitor’s laptop over one USB-C cable. Decide early, because it determines what lands at the table.

What echo cancellation does

The far end talks, your loudspeakers reproduce it, your microphones hear it along with the room’s reflections, and it goes back down the line. The far end then hears itself a fraction of a second late, which is uniquely disruptive to speech. Acoustic echo cancellation takes a reference of the outgoing far end signal, models how the room turns it into what arrives at each microphone, and subtracts the prediction. It must adapt continuously, so it is real processing per microphone channel, not a switch.

Where AEC lives

In a discrete system it lives in the conferencing DSP or matrix processor. Allen & Heath’s AHM processors, for example, take an optional module adding 12 channels of AEC, assigned through channel inserts on the far end and near end paths. That channel count is the practical constraint. In an all-in-one bar it is built in: Sennheiser’s TeamConnect Bar integrates automatic mixing and echo cancellation, including for microphones connected to it.

Display and sources

The industry reference for screen size is AVIXA’s display image size standard, V202.01:2016, usually called DISCAS. It defines two viewing categories. Analytical decision making works from a viewing ratio: distance to the farthest viewer divided by image height. Basic decision making adds the smallest element a viewer must resolve, as a percentage of image height, and requires a stated eye level (AVIXA gives typical values of 1200 mm seated and 1500 mm standing) and aspect ratio. AVIXA publishes free calculators for both.

Content type therefore matters as much as distance: a room watching video can use a smaller image than a room at the same distance reading spreadsheets. Check too that the bottom of the image clears the heads in front. A single display is simpler and easier to support; two earn their place where content and remote participants both need to be seen at a useful size.

Getting a guest laptop onto the screen is the commonest support call in corporate AV. Provide both HDMI and USB-C at the table, plus a USB tail for camera and audio if the room is bring-your-own-device. A presentation switcher that auto-switches on active input, scales to the display’s native resolution and handles EDID sensibly stops the display negotiating a resolution the laptop cannot drive. Wireless presentation suits visitors but needs a network policy agreed with IT and adds latency, so always keep a wired path.

Cable infrastructure

Cable pulled at first fix is cheap; adding it later is not.

• Floor boxes under the table. One per leg cluster, power and data segregated. A single box in a twelve seat table is not enough.
• Table modules. Flush plates or pop-ups with HDMI, USB-C, power and network at the seats people present from.
• Spare tails. A spare HDMI and Cat cable in the floor box, terminated and tested.
• Containment. Pull more than the design needs and leave draw cords.

Passive copper HDMI is a short in-room cable, not a structured cabling medium: as resolution and refresh rate rise the usable length falls, and failure at the limit is a black screen rather than gradual degradation. Beyond a short 4K run, use active optical HDMI or extend over structured cable with HDBaseT. HDBaseT 3.0 supports fully uncompressed 4K60 4:4:4 up to 100 m, with Category 6A U/FTP recommended for the full specification, and its 5Play feature set carries video, USB 2.0, Ethernet, control and power over one cable. See our HDMI versus SDI guide for more.

Conferencing hardware is network hardware. Ceiling microphones, DSPs, cameras and touch panels want structured cable and often power over Ethernet, and audio on Dante or AVB wants a managed switch with quality of service and its own VLAN, agreed with IT in advance.

Control: simple almost always wins

There is a simple test for how much control a room needs: does the building have AV staff? In most offices, schools and council buildings the answer is no, and the interface should then do three or four things and nothing else, on a plate or keypad labelled in plain words.

Full control systems driving camera presets, lighting, blinds and combining logic suit divisible rooms and lecture theatres where somebody is trained and accountable. They are wrong for a room operated by whoever arrives first, because every extra page is a chance to leave it in a state the next user cannot recover from. Automate what you can, lock the configuration, and keep any function you cannot explain in one sentence off the panel.

Acoustics: the cheapest big win

The most cost-effective improvement available to most meeting rooms is not electronic. A glass-walled boardroom with a hard ceiling is close to a worst case: parallel reflective surfaces, long reverberation, and microphones that hear the room rather than the talker. Beamforming helps, but it is still fighting the room.

Soft surfaces are the answer: carpet or a rug under the table, an absorptive suspended ceiling rather than plasterboard, fabric panels on one of each pair of opposing walls, blinds across glass, upholstered chairs. In refits, replacing a hard ceiling with a decent acoustic tile is often the single most valuable line item.

Then deal with noise, which in meeting rooms is nearly always the ventilation: diffusers over the table, or fan coil units in the void above a microphone. Get diffusers moved away from microphone and seating positions, and otherwise measure what you have before specifying microphones, because it changes which type works.

Accessibility and hearing access

Hearing accessibility is a legal consideration in the UK, not an optional extra. The Equality Act 2010 places a duty on service providers and public bodies to make reasonable adjustments for disabled people, including auxiliary aids, and an induction loop is the example most often cited for hearing aid users. Any room used for meetings that staff, members or the public attend should have hearing access considered at design stage and the decision recorded.

Commissioning and handover

1. Levels and gain structure set in the finished room, with furniture in and ventilation running. Echo cancellation adapts to the real room, so commissioning it in a bare shell proves nothing.
2. A far end test with a real person off site on the actual platform, with someone talking from every seat including the worst one. Ask them whether they hear themselves.
3. Presets saved and made the default, so yesterday’s meeting cannot break today’s.
4. Labelling on floor boxes, table plates, wall plates, rack panels and both ends of every cable.
5. A one-page laminated instruction on the table: how to start a meeting, how to share a laptop, how to adjust volume, and who to phone.
6. Training for at least two people per room, because the one person who understands it will be on holiday the week it matters.
7. The as-built handed over: IP addresses, DSP file and credentials, in the organisation’s own store.

Common mistakes

• Picture first, audio last. The screen is the visible spend, so it eats the budget.
• Too many open microphones. Every doubling costs 3 dB of noise and reverberation, and the gain that goes with it.
• No echo cancellation in a hybrid room. Confirm which device performs AEC, and over how many channels, before ordering.
• Loudspeakers aimed at microphones. A ceiling speaker directly above a table microphone creates the exact echo path everything downstream then has to fight.
• Laptop-only connectivity. One HDMI socket and no USB-C, or wireless presentation as the only path, will fail a visitor eventually.
• No spare cable at the table. Spare tails and containment cost almost nothing at first fix.
• No user training and no instructions. A well designed room with no one-page card is a badly performing room.

Popular picks from the shop

Conferencing hardware sells in project quantities, so these are chosen for relevance rather than sales ranking. All in stock.

Frequently asked questions

How many microphones does a boardroom table need?

It depends on type, not seat count. Goosenecks work at one per seat or shared between two, boundary microphones cover one to three seats depending on pattern, and ceiling arrays are specified by area.

Do I need a DSP, or is an all-in-one bar enough?

A bar suits huddle and small rooms where every talker sits inside its stated pickup area. You need a DSP once you have multiple microphone positions, distributed loudspeakers, sources to switch or reinforcement.

Why does the far end hear an echo of themselves?

Your microphones are picking up your loudspeakers reproducing the far end. Either nothing performs AEC, or it does not cover that channel, or the echo path is too loud for it.

What size screen do I need?

Work from the distance to your farthest viewer and the smallest detail people must read, which is what AVIXA’s DISCAS standard (V202.01:2016) formalises. Detailed documents need a larger image than video.

How far can I run HDMI in a meeting room?

Treat passive copper HDMI as a short in-room cable. For longer runs use active optical HDMI, or HDBaseT over structured cable, which supports uncompressed 4K60 4:4:4 up to 100 m.

Does a meeting room need a hearing loop?

Hearing access should be assessed wherever staff, members or the public attend meetings, because the Equality Act 2010 duty is to make reasonable adjustments. Loops are specialist work: BS 7594 requires a trained specialist, measured against IEC 60118-4.