How to Check a Studio Room Before You Treat It for Sound

Start by listening before you measure

Most acoustic problems can be heard before a single instrument is switched on. Take a presenter, a guest chair and a quiet half hour, and walk the room while someone reads a few paragraphs of script at normal volume. Stand where the cameras stand, not only where the talent sits. Clap once, sharply, and listen to how long the sound lingers and whether it rings, flutters or dies quickly.

Write down what you hear in plain words, with the position in the room next to each note. A phrase such as hard slap from the back wall near camera two is far more useful than a general remark that the room sounds boxy. These notes become the brief for any later measurement, and they keep everyone honest about which complaints are real and which are habit.

Do this at the hours the studio is actually used. Mid autumn brings heating that cycles on and off, wet-weather traffic noise and building ventilation running harder, all of which change what reaches the microphones.

• Listen from camera positions as well as talent positions
• Note each problem with a place in the room
• Repeat the check at the hours the studio is used

Find the noise that is not the room

Before blaming reflections, switch every microphone to a quiet gain and listen on headphones with nobody speaking. Air handling, lighting ballasts, monitor fans and rack cooling often supply a steady hiss or hum that treatment on the walls will never remove. Turn equipment off one item at a time and note what changes.

Doors and corridors matter just as much. A gallery door left slightly open, a lift shaft next to the set or a loading bay on the other side of a thin partition will be heard on air during the quietest moment of a bulletin. Record a minute of room tone at each position, because it gives you something to compare against after any change.

Separate these sources from the reverberation problem in your notes. Fixing noise at source is usually cheaper than treating the space, and it stops you buying absorption that cannot solve what is really wrong.

• Switch equipment off one item at a time
• Check doors, corridors and shared walls
• Record a minute of room tone at each position

Take simple measurements you can trust

You do not need a full laboratory to learn something useful. A calibrated measurement microphone, a laptop and free measuring software will give you a reverberation time and a frequency response at the presenter position. Place the microphone at mouth height, away from walls and desk surfaces, and take several readings with the set dressed as it is on air.

Run the measurement with the lights, desk and furniture in their normal places, since a bare floor and an empty set give misleading figures. Take at least three positions and compare them. Large differences between positions point to a particular reflection or standing wave, while similar figures everywhere suggest the whole room needs the same kind of attention.

Keep the files and label them by date and position. The point is not a perfect number but a record you can repeat after treatment to see whether anything improved.

• Measure at mouth height with the set dressed
• Take at least three positions
• Label and keep every file for later comparison

Match the treatment to the problem

Different faults call for different fixes. Flutter echo between parallel hard walls responds to absorption or diffusion placed at the reflection points. A low, boomy build-up usually needs thicker absorption or bass traps in the corners, since thin foam does almost nothing below a few hundred hertz. A dull, dead room is a sign of too much absorption and may need some surfaces uncovered.

Start with the first reflection points on the side walls and ceiling nearest the presenter, then deal with the rear wall behind the cameras. Avoid covering every surface evenly. Treat in stages and measure again after each, so you stop when the speech sounds natural rather than when the budget or the wall space runs out.

Remember the set itself. Glass, polished desks and video walls reflect strongly, and a change of backdrop can alter the sound more than a panel on the ceiling.

• Flutter echo: absorb or diffuse at reflection points
• Boominess: thicker absorption and corner traps
• Over-damped room: uncover some surfaces

Check it on air, not just in the room

Once treatment is in, test it through the real chain. Send a rehearsal through the desk, the gallery speakers and the output feed, and have someone outside the building or in a separate room listen to the programme sound. A room that feels pleasant to stand in can still sound distant or hollow after microphones and processing have done their work.

Try different guests as well. A quiet speaker leaning back, a loud one close to the microphone and a pair sharing a table all behave differently in the same space. Ask the sound operator what they find hardest to manage, because their gain riding is an honest measure of how much the room is still fighting them.

Record the test and compare it with your first set of notes. Where an old complaint has gone, strike it off. Where a new one has appeared, add it, and decide whether it is worth another round.

• Listen through the real programme chain
• Test with quiet, loud and shared-table speakers
• Ask the sound operator what is still hard

Keep a short acoustic log for the studio

Rooms change slowly. Furniture moves, panels sag, a new monitor wall goes up and nobody remembers what the room sounded like before. A single page kept in the studio folder, listing the date, the measurements, the treatment fitted and the problems still open, saves a great deal of guesswork a year later.

Include photographs of where panels sit and the heights at which they were hung, so a repair or repaint does not undo careful placement. Note any complaint raised by presenters or sound staff, even minor ones, because patterns show up when they are written down.

Review the log whenever the set is redesigned or a new camera position is added. Small changes to the room are cheaper to correct when they are caught early, and a studio that is heard cleanly week after week is usually one where someone kept the notes.