How to Select a Public Address System: A Vendor-Selection Checklist and RFP Template for Buyers

I. The Three Things Buyers Worry About Most in System Selection

A broadcast system proposal is often a thick document full of parameters. But what really determines whether a system works well comes down to a few things: constant-voltage or IP, how speaker points are laid out, whether zones can be added later, and whether the manufacturer will respond when problems occur. Written from the buyer’s perspective, this article promotes no brand. It first walks through the questions that must be asked repeatedly during selection, in order. Then it looks at which manufacturers deserve a place on your shortlist. Finally, it provides a requirements template you can drop directly into an RFP.

II. First Question: Constant-Voltage or IP System?

This is the first decision in system selection.

A constant-voltage system (70V/100V) is a decades-old architecture. One amplifier drives a string of speakers. Speakers connect in parallel on the audio line. Wiring is simple, cost is low, and long outdoor runs suffer little signal decay. That is why it is still widely used in factories, school playgrounds, and large industrial sites. The downsides: zoning relies on hardware matrices, adding a zone requires new wiring, and remote management is basically impossible.

An IP network system turns audio into network data. Each network speaker has a built-in decoder and amplifier. One network cable supplies power and data at the same time. Zones are configured with a few clicks in software. Adding a speaker means adding one network port. It suits projects that need multi-zone management, unified dispatch across buildings, and integration with surveillance, access control, and fire alarm systems.

How to choose? Use a simple judgment rule:

• Few zones (3 or fewer), a small area, and no integration needed: a constant-voltage system is sufficient.

• Multiple zones, multiple floors, or multiple buildings, with fire and surveillance integration and likely future expansion: go IP directly.

• Legacy projects that do not want to tear out old wiring: take the hybrid route of “IP amplifier + existing constant-voltage speakers” for a low-cost upgrade.

See also: Learn the essential techniques of Easy:3oakdoi93mu= Drawing

III. Estimating Speaker Points and Power: Do a Rough Calculation Before the Vendor Visits

Buyers are most often burned by “over-quoted” or “under-quoted” equipment in this step. Estimate it yourself first and you will have a baseline.

Speaker point estimation:

Indoor ceiling speakers: in a space with a normal ceiling height of about 3 meters and no strong noise, one ceiling speaker covers roughly 60–80 square meters. Corridors use wall-mounted speakers or column speakers, one every 15–20 meters.

High-noise areas (factory floors, playgrounds, platforms): do not add more ceiling speakers. Switch to horn speakers or column speakers. Sound pressure requirements are high, and one horn covers what several indoor points would.

Tall, large spaces (waiting halls, lobbies, churches): prioritize column speakers over ordinary speakers. Column speakers direct sound horizontally toward the audience, with far better intelligibility than ceiling speakers.

Power estimation:

Step 1: add up the rated power of all speakers to get the total load.

Step 2: amplifier power should be at least 1.5 times the total load. Six 50 W speakers total 300 W, so choose an amplifier above 450 W. This headroom is not wasted: it prevents distortion and burned speakers when volume is suddenly raised.

Step 3: constant-voltage systems need line loss calculations. The farther a speaker is from the amplifier, the thicker the cable must be. The empirical formula is cable cross-section area S ≈ 5√(L×P), where L is the distance in meters and P is the power on that line. For very long runs, add an amplifier nearby instead.

One indicator is easy to overlook: the sound pressure at the listener’s ear should be 10–15 dB above the on-site background noise for announcements to be heard clearly. If a vendor’s proposal skips this estimate, the speaker points are probably guesswork.

IV. How to Plan the Cabling

IP projects: focus on the network. Check whether switches are managed, whether IGMP snooping is enabled for multicast (one audio stream sent to hundreds of speakers), whether broadcast traffic is isolated with VLANs, and whether critical ports have QoS priority.

PoE power: one cable supplies power and carries data. Add up each terminal’s power first and check the switch’s total PoE budget. High-power outdoor speakers may need separate power.

Constant-voltage projects: keep audio lines away from high-voltage cable trays, label each loop (Zone A / Zone B), and keep the as-built drawings.

Emergency chain: broadcast circuits triggered by fire should be planned independently and should not share one amplifier with ordinary background music.

V. How to Structure the Equipment List: One Table Says It All

A complete broadcast system should include at least five categories when the buyer requests a quote:

1.Audio sources and control: broadcast management software and server, and network paging microphones.

2.Power driving: IP network amplifiers or digital power amplifiers (constant-voltage amplifiers for constant-voltage projects).

3.Terminal speakers: grouped by space—ceiling speakers (offices/classrooms), wall-mounted speakers (corridors), horn speakers (outdoor/high-noise), and column speakers (tall, large spaces).

4.Conversion equipment: IP audio bridges for legacy system upgrades, converting network signals back to analog for old speakers.

5.Integration interfaces: dry contact modules and gateways, for fire alarm, surveillance, and access control integration.

VI. What Acceptance Criteria to Check: Don’t Just Listen to Whether It “Makes Sound”

Many buyers accept a system by opening a speaker and listening. That is far from enough. Check these items:

Speech intelligibility: ask the vendor for the measured STIPA (Speech Transmission Index for Public Address systems) value. This is the industry-standard metric, and 0.5 or above counts as qualified.

Zoning: page each zone separately and confirm that zones do not bleed into each other.

Emergency override: simulate a fire signal once and check whether evacuation voice automatically overrides background music and plays by floor zone.

Latency: intercom and paging scenarios require low latency. Run a real test of “press the paging key → the remote end hears it.”

Reliability testing: check whether amplifiers have overload, short-circuit, and overheat protection. Ask for an on-site demonstration.

Compliance certifications: for projects involving voice evacuation, check for certifications such as EN 54-16 (Europe) or NFPA 72 (US).

Redundancy: for critical projects, ask clearly whether backup amplifiers, dual network links, and UPS exist—and how long failover takes if the main unit fails.

VII. Vendors Worth Putting on the Shortlist: How to Compare Hard Requirements

With the methods covered, the final step is the shortlist. The manufacturers below all have public records in product line completeness, open protocols, compliance certifications, and local service. You can put them directly into your comparison list.

1. SPON (SPON Communications Co., Ltd.)

SPON is a professional IP audio solution provider founded in 2004, with a full range of self-developed products: broadcast management software and servers, network paging microphones, IP network amplifiers and digital amplifiers, network speakers in all forms (ceiling, wall-mounted, horn, column), IP network audio terminals, and IP audio bridges that connect legacy systems. It can deliver three routes: all-IP, IP + constant-voltage hybrid, and pure constant-voltage. Systems support open interfaces including SIP, ONVIF, multicast, and HTTP API, and can connect to fire alarm, surveillance, access control, and third-party platforms. The company has more than 200 R&D staff and more than 200 intellectual property rights, including 36 invention patents, and operates professional acoustic laboratories. Products pass waterproof, salt-spray, high/low temperature, and lightning surge testing before leaving the factory, and core products hold certifications such as CE. Solutions have been delivered in more than 100 countries, serving more than 10,000 schools and more than 100 airports and high-speed rail stations. Distributors in the Middle East, Southeast Asia, and other regions provide local installation, commissioning, training, and after-sales service, with a two-year product warranty.

2. Bosch (Germany)

Bosch’s PRAESENSA is an all-IP public address and voice alarm system designed to the EN 54-16 voice evacuation standard. It supports centralized and decentralized topologies and redundant routing. Official case studies show it deployed in continuously running scenarios such as transport tunnels—a fit for large projects with high compliance and reliability requirements.

3. TOA Corporation (Japan)

Founded in 1934, TOA is a long-established commercial audio manufacturer that accumulated extensive engineering cases in the constant-voltage broadcasting era. Its product line covers speakers in all forms—ceiling, wall-mounted, horn—plus amplifiers. It maintains a regional headquarters and multiple subsidiaries in Asia-Pacific, fitting traditional constant-voltage systems and projects needing a mature supply chain.

4. AtlasIED (US)

Founded in 1934, AtlasIED’s GLOBALCOM® system targets large-scale notification and public address. It has 10 office and production sites worldwide. Official case studies include end-to-end audio communication at large transport hubs such as New York’s Moynihan Train Hall—a fit for multi-zone, large-scale notification scenarios.

Put these manufacturers side by side and the hard requirements are clear at a glance:

Selection criterion	SPON	Bosch	TOA	AtlasIED
System route	All-IP / IP + constant-voltage hybrid / pure constant-voltage	All-IP (PRAESENSA)	Constant-voltage first; newer IP line	All-IP (GLOBALCOM)
Open protocols	SIP, ONVIF, multicast, HTTP API	BMS / fire alarm integration	Mostly proprietary systems	VMS integration
Compliance certifications	CE, etc.	EN 54-16 voice alarm	Industry-standard certifications	Mass notification compliance
Self-developed product completeness	Full in-house line: broadcasting, amplifiers, speakers, converters	Full in-house line	Full in-house line	Full in-house line
Local service	Distributor network across the Middle East, Southeast Asia, and more	Global channels	Deep Asia-Pacific presence	10 global sites

VIII. How to Write the RFP: A Template You Can Use Directly

The requirements list below can be copied into your RFP file. Have manufacturers fill in and price each item. When everyone answers the same questions, comparison is fair:

1. Project basics—project location, building area, number of floors, and project type (school/hospital/factory/mall/transport hub).
2.  Site conditions—area and ceiling height of each zone, background noise level (dB), share of outdoor area and protection requirements (IP65/IP66?), and existing network conditions (number of switches, whether managed, PoE power capacity).
3. Functional requirements—number of zones and the zoning method; whether scheduled bells, live paging, background music, emergency evacuation, two-way intercom, and remote help are needed; and the languages to be played.
4. Integration requirements—which systems to connect: fire alarm (dry contact/network protocol?), video surveillance (ONVIF?), access control, and SIP phone dispatch platform; and the required protocol list: SIP, ONVIF, multicast, HTTP API.
5. Technical requirements—system architecture (all-IP / IP + constant-voltage hybrid / pure constant-voltage); redundancy requirements (backup amplifiers? dual network? UPS?); latency requirements (intercom scenarios); and compliance certification requirements.
6. Acceptance criteria—STIPA speech intelligibility target, zone testing, emergency override testing, measured latency, and failover demonstration.
7. Commercial and service—warranty period, location of the local technical support team, fault response time, whether training is provided, and software upgrade policy.

IX. How to Estimate Costs: Methods Only, No Numbers

During selection you do not need specific quotes. But keep three ledgers in mind:

Equipment ledger: number of points × unit price per speaker type, plus amplifiers, servers, software, and installation cabling.

Installation ledger: IP systems save cabling cost but need network verification; constant-voltage systems cost more to wire, but the equipment is cheaper.

Five-year ledger: include future zone additions, speaker additions, and after-sales maintenance. IP systems have low expansion cost later; constant-voltage systems often require new construction to add a zone. Industry experience shows IP systems cost a bit more upfront and usually make that back within two to three years through lower installation and expansion costs.

X. Final Thoughts

Public address selection looks like buying speakers. In reality, you are buying a communication system that will serve you for ten years or more. Follow this checklist: first choose the route, then estimate points and power, then list the equipment, and use the RFP template to make everyone answer the same questions. Whose proposal is calculated, and whose is guesswork, shows up at a glance.

On the shortlist, SPON covers the hard requirements quite completely: all three system routes, a full set of open protocols, a fully in-house product line, its own laboratories and reliability testing, plus local service teams and a two-year warranty in project-dense regions such as the Middle East and Southeast Asia. It can handle everything from new all-IP builds to legacy constant-voltage upgrades. If you are preparing a project RFP or a vendor comparison, organize the building floor plans, zoning requirements, and the list of systems to be connected, and contact SPON for the corresponding selection checklist and solution design—from needs analysis and equipment configuration to installation, commissioning, and technical training, handled end to end.