PA SYSTEM · BACKGROUND MUSIC · CONFERENCE AUDIO
PA systems and background music
for every zone, every room,
every event.
Own-factory manufacturer of background music, public address, voice evacuation, conference audio and ballroom sound. We build the products, support ODM and OEM, and configure the complete system — one brief, one combined proposal.
15 m Maximum to nearest loudspeaker · 8 m Last loudspeaker to corridor end · +15 dB Emergency level above ambient · 100 V Constant-voltage distribution
Own-factory manufacturing
Our product families are built in our own factory, with production, testing and packing under one quality process.
ODM / OEM
Model naming, brand marking, packaging, accessories and configuration for distributors and private labels.
Full system configuration
BGM, PA, voice alarm, conference, AV and ballroom designed and configured as one coordinated package.
One combined proposal
Send the room list once. We return one equipment schedule, one interface list and one commercial proposal.
Send the briefThree lines
One manufacturer, three design languages
Public address is a zoning and life-safety discipline. Conference audio is a speech-intelligibility discipline. Ballroom sound is a music and event discipline. They share equipment, not assumptions.
BGM & public address
One head end for music, paging, scheduled bells and fire evacuation. Designed zone by zone, with the 100V line and the amplifier headroom calculated.
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Conference audio & AV
Meeting microphones, room sound reinforcement, discussion and voting, control and display. The room is designed as one system, not a rack of boxes.
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Ballroom & event sound
Line arrays, subwoofers, stage monitors and wireless microphones for banquet halls, convention centres and event venues. Meeting and banquet presets included.
View the lineProduct families
The building blocks of a working audio system
Thirteen families across three lines. Each page explains what the block does, how it is selected and what has to be confirmed before a price.
PA line · coreBroadcast control & amplifiers
Broadcast hosts, zone controllers, mixer amplifiers and IP amplifiers for background music, paging and emergency override — specified as one signal chain.
PA line · outputCeiling, horn, column & wall loudspeakers
Ceiling, horn, column, wall and landscape loudspeakers for corridors, halls, factories, stations and outdoor areas — selected by coverage and environment, not by wattage alone.
PA line · controlZone paging & paging consoles
Desktop paging consoles, remote paging stations, zone selectors and timed message players for schools, hospitals, stations and commercial buildings.
PA line · networkedIP network audio
IP audio terminals, network amplifiers, paging consoles and cloud or local management for campuses, towers and distributed sites.
Conference line · speechConference microphones & discussion
Conference hosts, chairman and delegate units, gooseneck microphones, paperless terminals and discussion systems for boardrooms, councils and lecture halls.
Conference line · reinforcementConference room sound reinforcement
Ceiling, wall and line-array loudspeakers, amplifiers and audio processing for meeting rooms, boardrooms, lecture theatres and multi-purpose halls.
Conference line · visualConference display & projection
Projectors, projection screens, commercial displays, video walls and signal distribution for meeting rooms, boardrooms, lecture theatres and command centres.
Ballroom line · reinforcementBallroom & stage sound
Line arrays, point-source loudspeakers, subwoofers, stage monitors and amplifiers for hotel ballrooms, convention halls and event venues.
Ballroom line · stageWireless microphones & stage lighting
Handheld, lavalier and headset wireless systems, antenna distribution, stage lighting and control for ballrooms, event venues and multi-purpose halls.
One building, three systems
The same building may need all three
A hotel can have public-area BGM, conference rooms and a ballroom. The lines stay technically independent, but we manufacture the equipment and return the interfaces, priority rules, documents and price as one combined package.
The loudspeaker network may be shared; the fire override, monitoring and documentation are not shared by accident. Those are agreed per system.
Application designs
Start from the space, not the box
Schools, hospitals, mosques, hotels, factories, transport terminals and venues. Each page follows the physical need, the zoning and the calculation.
Schools & campuses
One bell, one paging system and one evacuation path across classrooms, corridors, playgrounds and canteens.
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Hotel ballrooms
Meeting by day, banquet by night, with a system the hotel AV team can run.
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Hospitals & healthcare
Patient announcements, staff paging and evacuation in one system, with the privacy and zoning a hospital actually needs.
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Meeting rooms
The everyday room: display, ceiling loudspeakers and a microphone that works on the first attempt.
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Factories & industrial sites
Announcements that cut through machinery noise, indoors and across the yard, without becoming a hazard.
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Convention centres & multi-purpose halls
Dividable halls, large audiences and a technical team that needs the room to reconfigure quickly.
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Offices & commercial buildings
Background music, floor paging and evacuation in a building that has to feel calm every day and work under pressure once.
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Airports, stations & transit
Long concourses, hard surfaces and constant background noise — announcements that stay intelligible at the farthest gate.
View application designDesign desk
Two calculations before the first price
A public-address system and a conference room fail for different reasons. The PA calculator checks coverage, tap load and amplifier headroom. The AV planner checks display size, loudspeaker count and microphone count. Both return a starting point and the assumptions that still need confirmation.
PA
Zoning & loudspeaker calculator
Area, ceiling height, zones, target SPL → speaker count, spacing, tap load and amplifier size.
Open the PA calculatorAV
Conference room planner
Room size, seats, use → display size, loudspeaker count and microphone count.
Open the AV planner- Speaker spacing from ceiling height and coverage angle
- Connected tap load and amplifier headroom
- Display size from the farthest seat
- Microphone count from the seating plan
Illustrative schedule. The project calculation uses the actual room data.
Why SONTRA
A manufacturer that shows the design
The products come from our own factory. The system still has to be calculated: zoning, coverage, interface list and handover are what turn a box into a working installation.
Written design output
Zoning, SPL, tap load, amplifier headroom and line loss are documented before the equipment list is fixed.
Own-factory manufacturing
Our product families are built in our own factory. Production, testing, packing and model documentation stay under one quality process.
ODM / OEM production
OEM private label and ODM configuration on our own platforms: model naming, brand marking, packaging, accessories and documents.
One combined proposal
Send the building data once. PA, conference, ballroom and AV come back as one equipment schedule, one interface list and one commercial proposal.
How a project runs
Five steps from a building brief to a shipment
No price before the coverage is checked. No model list before the zones are agreed. One brief returns one combined proposal; no shipment before the sample and document pack are approved.
Get a combined proposalSend the building data
Floors, zones, room sizes, ceiling height, seats or tables, fire interface and drawings link. A plan sketch is enough to start.
We calculate the coverage
Loudspeaker spacing, tap load, amplifier headroom, 100V line loss, display size and microphone count are checked before a product is named.
Build the equipment chain
One family per function, built in our factory, with alternatives where the budget or the certification route requires them. The model list follows the design.
Review the documents
You receive the zoning concept, the equipment schedule, the interface list and the questions that still need an answer.
Sample, ship, support
A sample or pilot batch is tested before the full order. Export packing, documents and a commissioning checklist go with the shipment.
Questions
Frequently asked questions
The questions that usually decide the scope: loudspeaker count, amplifier size, fire interface, certification and who installs the system. If your question is not here, send it with the building data.
Ask an application engineerWhat is the difference between BGM, PA and voice alarm?
BGM (background music) is the everyday music and atmosphere function. PA (public address) is live and scheduled paging plus general announcements. Voice alarm is the life-safety function that overrides both and must meet the fire standard. The three can share a loudspeaker network, but they have different priority, monitoring and documentation requirements.
Can one manufacturer cover the PA system, the conference rooms and the ballroom?
Yes. One brief can return one combined package: public address, conference audio, AV, ballroom sound and the interfaces between them. The systems keep their own design targets, but the equipment schedule, priority rules, interface list and commercial proposal are coordinated.
Do you design the system or only supply equipment?
We do both. We manufacture the products, configure the complete system and supply the equipment. The design output includes the zoning concept, loudspeaker schedule, tap-load and amplifier calculation, 100V line check, interface list and a commissioning checklist. Installation and statutory acceptance are carried out by the local licensed contractor unless a different scope is agreed in writing.
Are you a manufacturer?
Yes. Our product families are manufactured in our own factory in Guangzhou. Production, testing, packing and model documentation are controlled under the same quality process, so we can confirm the platform, the label and the delivery schedule directly.
Do you offer ODM and OEM?
Yes. We support OEM private-label production and ODM configuration around our own platforms, including model naming, brand marking, packaging, accessory kit and documentation. The exact scope, MOQ and certification route are confirmed per model before the order.
How do you handle EN 54 or local fire certification?
Certification is model-specific. Where the project requires EN 54-16 control equipment or EN 54-24 loudspeakers, we confirm the certificate scope for the models offered and provide the documents. Where a local standard applies, we confirm the accepting authority’s requirements before the quote is fixed. We do not describe a product as certified unless the certificate covers that model and use.
What information do you need for a quote?
Building type, number of floors, zone list, room sizes, ceiling height, seat or table count, fire-alarm interface, existing cabling, country and required timeline. If you have drawings, send a link. If not, a sketch and the room schedule are enough to start.
One brief, one combined proposal
Send the building once. Get the whole system back.
Tell us the building type, zones, room sizes, ceiling height, seat or table count, fire interface and any ODM/OEM requirement. Our own factory and system team return one combined proposal: equipment schedule, interface list and open questions.
Reply within 48 hours · drawings welcome · no obligation