Acoustic checks to make before the winter broadcast schedule

Most live studios get quieter on the calendar at some point between the end of summer and the winter schedule, and that gap is the cheapest time to look at the room. Treatment work needs a clear floor, sometimes a few days of dust and ladders, and nobody enjoys doing it between a morning bulletin and an evening interview. I would rather see a producer book a measurement visit now than discover a problem during the first cold snap of live coverage.

There is a practical reason as well. Rooms change with the seasons more than people expect. Heating comes on, windows stay shut, extra equipment goes into the gallery, and the sound of the building shifts with it. A studio that behaved well in July can sound noticeably different by November, and a measurement taken in these weeks reflects the conditions the room will actually work in over the winter.

The first step is always measurement, not treatment. We take a reverberation reading across the studio floor and in the gallery, note where the room rings, and record the background noise with the lighting and ventilation running as they would be on air. This gives a number for each room and a map of where the trouble sits, which is far more useful than a general impression that the place sounds a bit lively.

Buying foam panels first is the mistake I see most often. Panels placed where they happen to fit will absorb the wrong frequencies and leave the real problem untouched, usually the low and mid range that muddies speech. Duncan, who leads our acoustics work, will not specify anything until he has the readings in front of him. That discipline saves clients money, because treatment is then placed where the measurements show it will make a difference.

• Reverberation time in studio and gallery
• Background noise with all systems running
• Position of any strong reflections near the presenters

Autumn brings its own noises. Fans and air handling work harder as the weather turns, and a unit that was barely audible in summer can become a steady hum under a quiet interview. Rain on a roof light or a lightweight studio roof is another one, and it tends to be discovered only on the first wet day of a live programme. It is worth listening for these before the schedule fills up.

The remedy is rarely dramatic. Often it means slowing a fan, adding a short duct silencer, moving a noisy rack away from the gallery wall, or isolating equipment that vibrates against a stand. These are small jobs, but they need to be found with the room running normally. A walk-round with the studio at working temperature, and someone listening with headphones at the presenter's position, will uncover most of them in an afternoon.

Echo is only half of the story. What matters on air is whether a guest's voice stays clear and consistent, and that depends on where people sit as much as on the walls. A desk placed near a hard corner, a glass backdrop behind the presenter, or a reflective floor under the interview chairs can all colour the voice in ways that no microphone choice will quite cure.

The gallery deserves the same attention, because the people who mix and monitor speech work there all day. If the control room is too reverberant, the engineer compensates by turning things up or down in ways that the audience then hears. A modest amount of treatment behind the desk and on the ceiling can make monitoring honest again. Fixing the gallery first is often the quickest route to better sound on air.

• Check desk positions against hard corners
• Look at glass and reflective floor surfaces
• Treat the gallery as carefully as the studio

Once the readings are in, the work can be divided by disruption. Some measures need no downtime at all: heavy curtains, freestanding absorbers, repositioned furniture. Others, such as wall or ceiling panels and duct work, need the room empty for a day or two. Knowing which is which lets a producer slot the work into a gap rather than cancelling a recording.

I advise clients to bring the most disruptive jobs forward into early autumn and leave the adjustments for later. Fine tuning with the presenters present, once the main treatment is in, takes only an hour or so and can often be done between programmes. A short written summary of what was measured and what was changed also helps whoever manages the room next year, because the next person will want to know why a panel sits where it does.

You do not need us to begin. Before the winter schedule starts, clap once in the middle of the studio and listen to how long the sound lingers, then sit in the gallery with the equipment running and notice what you can hear that you could not hear in summer. Those two minutes tell you whether a proper measurement is worth booking.

If the answer is yes, write down the times of day the room is at its noisiest and bring them to the visit. Knowing when a problem occurs often points straight to its cause. Everything else, the readings and the choice of treatment, can follow from there in a clear order, and none of it needs to interrupt your programmes.

• Clap test in the studio centre
• Listen in the gallery with all systems on
• Note when noise is worst, and tell us