Hiring a PA system should be straightforward. But if you’ve never done it before, or you’ve been burned by poor sound at a previous event, it can feel like a minefield.
How many watts do you need? What’s the difference between a column speaker and a line array? Do you need subwoofers? What about monitors?
The honest answer is: it depends. But “it depends” is only useful if you know what it depends on. This guide breaks that down clearly, covers every main system type, and gives you a practical checklist to work through before you book.
Why getting PA size wrong is such a common problem
There are two failure modes. Both are avoidable.
The first is under-speccing. A system that’s too small for the room means the audio engineer has to push it hard to reach the back. Pushed speakers distort. Distorted sound is tiring to listen to and makes the event feel amateur, regardless of how good everything else is.
The second is over-speccing. A system that’s far too powerful for the space creates problems too. It’s harder to control, more likely to cause feedback, and you’ve spent money on capability you’ll never use.
The sweet spot is a system that fills the room cleanly, gives the operator headroom without having to push it, and suits the nature of the event. Getting there requires thinking about a few key things before you pick up the phone.
The five things that determine what PA system you need
1. How many people are attending
Audience size is the most obvious factor, but it’s not the only one. A hundred people in a tall Victorian ballroom need a different system to a hundred people in a low-ceilinged conference suite. Headcount gives you a starting point. The venue gives you the full picture.
2. The room or space
Indoor rooms have walls, ceilings, and surfaces that reflect sound. Some rooms are naturally live and reverberant — hard floors, high ceilings, glass and stone surfaces. Others are naturally dead — carpets, curtains, acoustic panels. A live room can make a modest PA sound bigger than it is. It can also turn a powerful PA into an unintelligible mess if it’s not managed carefully.
Outdoor spaces are the opposite problem. Sound disappears into open air. You need considerably more power outdoors than indoors for the same audience size, and speaker placement becomes critical.
3. What the PA is being used for
Speech and music have very different requirements. A PA system for presentations and speeches needs to be clear and intelligible above everything else. Articulate mid-range frequencies, good coverage across the whole room, and enough control to prevent feedback when microphones are in use.
Music demands more. You need the system to handle low frequencies properly, respond dynamically to changes in volume and tone, and perform consistently over a long period. If it’s both speech and music at the same event, the system needs to do both well.
4. Background noise levels
A conference in a quiet hotel suite is very different to an outdoor product launch next to a busy road, or a party in a venue with a bar full of people chatting. The more background noise there is, the harder the PA has to work to cut through it. Factor this in when thinking about system size.
5. Noise restrictions
Many London venues, especially those in residential areas or with noise licences, have strict limits on sound levels. Your PA system needs to be capable of sounding good within those limits, not despite them. A well-chosen, properly set-up system will do that. An oversized, badly configured one will hit the limiter and sound dreadful.
Always tell your AV company about any noise restrictions upfront. It affects equipment choice, speaker placement, and how the system is configured.
PA system types explained
Small portable systems — up to around 100 people
These are self-powered column speakers or compact active speaker systems. They’re quick to set up, easy to position, and more than capable of covering a small to medium-sized room for speech, background music, or a simple presentation.
Best for boardroom presentations, small seminars, intimate private parties, small workshops, places of worship with modest congregation sizes, and community events.
They handle clear speech reproduction, background music playback, and a single presenter with a microphone really well. Where they struggle is in large or complex rooms, high background noise environments, live music with a full band, or anything that needs significant bass or dynamic range.
If your event is relatively simple and the guest count is comfortably under 100, a portable active system is likely all you need. A decent one sounds genuinely good. Don’t assume small means poor quality.
Mid-range PA systems — 100 to 300 people
This is where most corporate events, private parties, weddings, and medium-sized conferences sit. The system gets more substantial. Larger active speakers, often with dedicated subwoofers for bass, and more sophisticated signal processing.
At this level, speaker placement starts to matter more. A single pair of speakers at the front of a long room won’t give you even coverage. You may need delay speakers further back to make sure guests at the rear hear as clearly as those at the front.
Best for conferences and AGMs, award ceremonies, product launches, weddings, corporate parties, and medium-sized live music events.
They handle mixed speech and music, multiple microphone sources, panel discussions, live bands with a modest stage setup, and longer events where consistency matters. Where they struggle is in very large or irregularly shaped rooms, outdoor events with big open spaces, or high-energy festival-style live music that demands serious volume.
This is also the level where having an experienced operator on-site stops being optional and starts being essential. Managing multiple microphone inputs, balancing speech against music, and keeping everything under control throughout a multi-hour event requires someone who knows what they’re doing.
Large line array systems — 300 people and above
Line arrays are what you see hanging either side of the stage at concerts, large conferences, and major corporate productions. They’re designed to throw sound consistently over long distances, maintain even coverage across a wide area, and perform at high volume without distortion.
A line array system isn’t just bigger speakers. It’s a fundamentally different approach to sound distribution. The physics of how a line array behaves in a room means it can cover far more ground with far greater consistency than a conventional speaker setup.
Best for large conferences, flagship corporate events, award ceremonies for 300 or more guests, concerts and live music events, large-scale product launches, and festival stages.
They handle large and complex rooms, long throw distances, high-volume live music, and events where consistent coverage from front to back is critical. Where they struggle is in very small or low-ceilinged rooms where the system can’t be flown properly, or events where the budget doesn’t stretch to the crew needed to operate it correctly.
Line array systems require experienced engineers to set up and operate. The rigging, the processing, the tuning of the system to the room — all of it takes expertise. If someone quotes you a line array and doesn’t mention a skilled engineer to go with it, ask why.
Outdoor and festival systems
Outdoor sound is a different discipline. There are no walls to help contain and direct the sound. It disperses into open air rapidly, which means you need more power, more coverage, and more careful planning around speaker placement and directivity.
Weather is a factor too. Equipment needs to be protected. And noise restrictions at outdoor venues are often stricter than indoor ones. Neighbouring properties, local licensing conditions, and environmental noise assessments can all come into play.
Festival setups range from a modest outdoor stage for a community event to full-scale multi-stage productions. The complexity and the crew required scale accordingly.
Best for outdoor corporate events, garden parties, festivals, outdoor ceremonies, street events, and sports events.
Key things to think about are power supply (generators may be needed), weather protection, noise restriction compliance, audience distribution across open space, and site logistics for delivery and rigging.
For any outdoor event of meaningful size, a site visit from your AV company beforehand is strongly recommended. The variables are too unpredictable to quote and plan accurately from a description alone.
PA systems for specific event types
Indoor corporate events
The priority is clarity. Every word from the stage needs to be heard cleanly at every seat in the room. Multiple microphone inputs are common — lapel mics for presenters, handheld or lectern mics, floor mics for audience Q&A. The system needs to handle all of these without feedback and without the operator constantly fighting the desk.
For anything above a small meeting room, a professionally specified and operated PA system is worth every penny. Poor audio at a corporate event reflects on the organisation running it.
Outdoor events and festivals
Scale and coverage are the priorities. You’re working against open air, background noise, and often a dispersed audience that doesn’t stand in a neat block in front of the stage.
Think carefully about how the audience will move around the site. Are there multiple areas that need coverage? A main stage and a secondary space? Each needs its own solution. Delays and distributed speakers may be needed to cover a wide area evenly.
Plan for more power than you think you need. Outdoor events almost always benefit from the headroom.
Live music and concerts
Live music demands the most from a PA system. Dynamic range, low-frequency reproduction, volume, and consistency over a long performance are all non-negotiable.
For a live band, you also need to think about stage monitoring — speakers facing back toward the performers so they can hear themselves. A great front-of-house system with inadequate monitors leads to a poor performance, which leads to a poor event regardless of how good the sound is for the audience.
The engineer matters as much as the equipment here. A skilled live sound engineer working a good system will always beat an inexperienced operator working a great one.
Private parties and weddings
Weddings in particular often have multiple audio requirements across the day. A ceremony, a drinks reception, a dinner, and an evening party. Each has different needs, different room dynamics, and different volume expectations.
For the evening party and dancing, subwoofers are almost always worth including. Bass is what gets people on the dancefloor and keeps them there. A PA system without proper low-end sounds thin and flat for music, however good it is for speech.
Discuss the full run of the day with your AV company so they can design a system that works for each phase rather than just the headline moment.
Common mistakes to avoid
Assuming the venue’s house system is good enough. Many venues have installed house systems that were chosen for cost rather than performance. They may be old, poorly maintained, or simply not powerful enough for your event. Always ask your AV company to assess the house system before assuming you can rely on it.
Not thinking about microphones alongside the PA. A PA system is only as good as the signal going into it. A poor-quality or incorrectly chosen microphone will let down even the best system. Tell your AV company exactly how the mics will be used and let them specify accordingly.
Skipping on-site crew to save money. Hiring equipment without an operator for anything beyond the simplest setup is a false economy. Someone needs to manage levels, handle transitions, respond to feedback, and keep everything running smoothly in real time. That’s a skilled job. Budget for it.
Forgetting about power. PA systems need power. Large systems need a lot of it. Make sure your venue has adequate power supply and that your AV company knows about it in advance. For outdoor events, generator hire may be needed. Factor that in early.
Booking too late. Good AV companies with quality equipment and experienced crew get booked up, especially on Fridays and Saturdays. The closer you leave the booking, the fewer options you’ll have.
Not mentioning noise restrictions. Noise limits affect everything. System choice, speaker placement, how the engineer configures the system. Find out if your venue has restrictions and tell your AV company before they quote. It’s much easier to design around limits from the start than to retrofit a solution on the day.
Quick sizing checklist
Before you call an AV company, work through these questions. The more of them you can answer, the more accurate your quote will be and the more likely you are to end up with the right system.
About the event: What type of event is it? Speech, music, or both? How many guests are attending? How long will the event run? Are there multiple phases with different audio needs?
About the venue: Is it indoor or outdoor? What are the approximate room dimensions and ceiling height? Is the room acoustically live or dead? Are there any noise restrictions? What power supply is available? What are the load-in and load-out times?
About the audio sources: How many microphones are needed and what type? Lapel, handheld, lectern, audience Q&A? Will there be live music and how many inputs from the stage? Will there be audio playback from a laptop or DJ?
About crew: Do you need a technician on-site throughout? Is there anyone in-house who can assist, or does the AV company need to be fully self-sufficient?
The bottom line
The right PA system is the one that fills your space cleanly, suits your event type, works within any restrictions, and is operated by someone who knows what they’re doing. It doesn’t have to be the biggest or the most expensive. It just has to be the right fit.
If you’re not sure what you need, that’s what we’re here for. Tell us about your event and we’ll advise you honestly. No upselling, no jargon, just a straight answer on what will work.