The School Bought New Curtains. Why Was the Hall Still Hard to Hear In?

The new curtains are finally up in the school hall. They frame the stage beautifully, soften the afternoon glare and make the room feel ready for parents’ day. Then the headteacher tests the microphone. At the front, the announcement is clear. Near the back, the beginning of the next sentence seems to arrive before the previous one has finished fading. A teacher asks whether thicker curtains would help. The operator reaches for the volume control.

Picture being the administrator who must approve the next expense. The school has already paid for something everyone expected to improve the sound, yet the original complaint remains: pupils hear a voice but miss the instructions. Another supplier proposes larger speakers. Someone recommends covering the walls with foam. Each suggestion sounds plausible, but none answers the most important question. What, exactly, is preventing the words from being understood?

This is where a useful audio discussion needs to slow down. A hall can have too much lingering sound, uneven speaker coverage and competing background noise at the same time. Those problems interact, but they are not interchangeable. Curtains may help one part of the picture without resolving the others. Understanding the difference gives the school a better basis for spending than simply buying the next thing described as “soundproof”.

Start with what happens to a single spoken word. Sound travels from the loudspeaker directly towards a listener, but it also reaches the floor, walls, ceiling and other surfaces. Some reflected sound arrives soon after the direct sound and can support the impression of the voice. Other energy arrives later or persists through repeated reflections. When that lingering sound becomes excessive for speech, it overlaps the details of the next word. The problem is not that sound failed to reach the pupils. Too many versions of it reached them over time.

The distinction is easier to recognise with an announcement than with music. A sustained musical note may still sound pleasant in a lively room, while a sequence of names, dates or instructions becomes difficult to follow. The brief consonants that distinguish similar words are particularly vulnerable to being masked by lingering sound and noise. A pupil may hear the rhythm and loudness of the headteacher’s voice without confidently identifying which classroom or meeting time was announced. Asking whether the hall is loud enough misses that difference.

Distance adds another layer. Near a properly aimed loudspeaker, the direct voice can dominate what the listener hears. Farther away, its advantage over the room’s reflected sound may diminish. A demonstration beside the stage can therefore sound reassuring while the rear seats remain tiring to listen from. A speaker’s coverage pattern and aiming matter because the system should put useful sound where people sit, rather than unnecessarily exciting large reflective surfaces.

Turning up the same speaker raises both its direct contribution and the sound it sends into the room. It may help if the announcement is simply too quiet relative to background noise, provided the system has appropriate headroom and the level remains comfortable. But it does not automatically improve the balance between direct and reflected sound at a difficult seat. That is why repeated volume increases can make the front rows uncomfortable without giving the back rows the clarity everyone expected.

Now consider what the curtains actually change. Soft materials can absorb some of the sound energy that reaches them rather than reflecting it all back into the room. The amount and frequency range of that absorption depend on the fabric, its construction, fullness, mounting and the area covered. Thin decorative fabric pulled flat against a window should not be assumed to perform like a substantial, tested acoustic curtain. Equally, an attractive heavy curtain is not automatically suitable for every frequency or every installation.

The location of the material matters as much as its appearance. Curtains across the windows may reduce some reflections from that side of the room, while leaving a large ceiling and bare rear wall untreated. If those remaining surfaces contribute strongly to the problem, making the window curtains thicker may deliver less benefit than expected. A room can also become less bright-sounding without its more persistent low-mid-frequency problems being adequately addressed. Less sharp is not necessarily the same as more intelligible.

This explains why buying random patches of thin foam is not a dependable next step either. Absorbers differ in how they perform across frequency, and a token quantity of material may make little difference in a large hall. Successful treatment is not about covering whichever wall is easiest to reach. It is about selecting suitable absorption, placing enough of it where it addresses the room’s behaviour and preserving the conditions needed for the hall’s other activities. For a significant project, that calls for a competent acoustic assessment rather than a photograph-based guess.

There is also an important distinction between absorption and isolation. Absorption manages sound within the hall. Isolation concerns sound passing into or out of it. Curtains that soften internal reflections do not necessarily prevent traffic, playground activity or a neighbouring lesson from competing with speech. If a passing vehicle masks the announcement, that observation points towards a different part of the problem from words continuing to linger after the speaker has stopped. Both may need attention, but they should not receive the same diagnosis.

Ventilation makes this especially practical in a busy school. Closing doors or windows may reduce some outside noise, yet the room still needs appropriate airflow and safe access. An audio plan that works only when an occupied hall is uncomfortably sealed is not a complete plan. Observe the space in its normal operating condition, including the openings staff actually use, rather than approving a demonstration that cannot be repeated during assembly.

Try one listening exercise before the next purchasing meeting. Ask a staff member to read short, unfamiliar phrases through the normal microphone while colleagues listen from the front, centre and rear. Include names, numbers and brief instructions, because familiar material can be guessed even when the sound is unclear. Keep microphone distance and speaking style consistent, leave the PA controls unchanged and have listeners write down what they actually hear. The aim is to locate misunderstandings, not to reward people for recognising a rehearsed sentence.

Where curtains can be operated safely from floor level, compare them open and closed under otherwise similar conditions. Use equivalent fresh phrases rather than repeating the same answers, and do not turn the system up between comparisons. Note whether missed words become less frequent, whether speech feels less tiring and whether particular seating areas remain poor. This is a practical observation exercise, not a laboratory measurement, but it gives the school a much more useful record than “it sounded better to me”.

The pattern of the results helps frame the next investigation. Consistently poor rear-seat results may justify checking coverage and the balance of direct and reflected sound there. Errors that increase mainly when outside activity starts suggest background noise deserves closer attention. A clear improvement when curtains close suggests they are contributing usefully, though it does not establish that more curtains are the complete answer. These are clues to investigate, not automatic diagnoses or permission to order equipment without checking further.

A sharp clap can reveal an obvious flutter or lingering tail, but it cannot tell the school exactly which treatment to buy. A phone recording has limits too: its microphone position and automatic processing may make the room sound different from what a seated listener experiences. For a substantial upgrade, ask the assessor to explain the measurements, listening observations and proposed changes in plain language. The team should understand what each part of the quotation is intended to improve.

Repeat the listening check under representative occupied conditions before signing off the final setup. People and their clothing alter absorption and scattering, so an empty hall does not behave exactly like a full one. That does not guarantee that occupancy will solve the problem, and it is not a reason to skip testing. It means the acceptance check should reflect the real seating layout and use of the room, not only a quiet demonstration with three adults beside the sound desk.

The eventual solution may combine better aiming, appropriate coverage, targeted acoustic treatment and control of competing noise. Additional speakers sometimes help cover difficult areas, but their positions, levels and timing need to be designed together. Simply adding another loudspeaker at the back can create overlapping arrivals and a new clarity problem. The question is how the system serves the listeners as a whole, not how many boxes the budget can buy.

Finally, judge the plan against the school’s actual programme. Assembly speech, a choir rehearsal, a music performance and an examination briefing do not place identical demands on the room. Ask for appropriate material-performance information and a professional installation plan that accounts for mounting, access, ventilation and suitable fire performance. Agree on the listening checks that will demonstrate improvement before the work begins, so the outcome is not judged only by how finished the room looks.

At Zamar Audio Solutions, choosing a school PA starts with where the pupils sit, what they need to understand and what the hall is doing to the sound. Equipment selection makes sense only within that picture. The goal is not to dismiss the curtains or sell a bigger speaker, but to give the school a clear reason for every next step. Define the problem first, then choose a system that fits the plan instead of paying for another guess. Explore PA systems for a properly planned school setup.