The Tools and Methods We Use to Measure a Studio Room
A look at the measurement tools, test signals and treatment materials we rely on when assessing a studio, and how each one informs the advice we give.
Starting with a measurement microphone
Every acoustic assessment I carry out begins with a calibrated measurement microphone on a stand, placed where a presenter's head would be. Ears are good at noticing that a room sounds wrong, but they are poor at telling us why. A microphone with a flat response gives us a record we can compare from room to room and from visit to visit, which matters when a client wants to know whether treatment has actually helped.
We usually take readings at several positions rather than one: the host chair, the guest chair, beside each camera and at the gallery window. Voices behave differently across a set, and a spot that sounds fine for an interview can be muddy a few metres away. Mid autumn is a useful time for this work, because heating systems are coming back on and we can measure the room with its real background noise present.
I note the microphone height, the distance from nearby walls and the state of the room, including whether doors are open and monitors are running. Without those notes a measurement is hard to repeat.
Test signals and what they reveal
We excite the room with a swept tone played through a small loudspeaker, then record the response. The sweep lets us calculate how long sound takes to fade away at different frequencies, which is the reverberation time most people have heard of. What matters more in a television studio is how that decay varies across the spectrum. A room can look acceptable on average while a low-frequency ring makes male voices boom.
A simple handclap or a balloon burst also has its place. It is crude, but it tells us quickly whether a flutter echo is bouncing between two parallel walls, something a sweep can hide. I often use the clap first on arrival, as a way of deciding where to look more carefully.
- Swept tone for decay time by frequency
- Handclap check for flutter echo between parallel walls
- Pink noise to compare levels across the set
Measuring the noise floor
Reverberation gets the attention, yet unwanted noise is the problem clients describe most often. With the studio quiet and the equipment switched on, we record the background level over several minutes. Ventilation, lighting transformers, monitor fans and traffic through a thin wall all contribute, and each has a different character.
Once we have a figure, we run the room in stages. Switching off the extraction briefly, or powering down a rack, shows which source is responsible. This is slow, plain work, but it stops us recommending thick wall treatment when the real culprit is a single noisy fan unit.
We write the findings up in order of how much they affect speech on air. A tonal hum is usually more distracting to a viewer than a higher but steadier hiss, so the ranking is not simply by loudness.
Choosing treatment materials
Absorbent mineral wool panels are the material I reach for most often. They are predictable, they come in known thicknesses, and the performance of a panel depends on its depth and the air gap behind it. Thin foam tiles absorb mainly high frequencies, which can leave a room sounding dull while the real problem, low-frequency build-up, goes untouched.
Where a set needs to look good on camera, we cover absorbers in acoustically transparent fabric and match the colour to the design. Diffusing surfaces such as slatted timber help in larger rooms where too much absorption would make speech feel lifeless. Heavy curtains on tracks are a useful, adjustable option for studios that serve more than one purpose.
I always size the treatment against the measurements instead of a rule of thumb, and I say plainly when a corner needs a deeper trap than the budget first imagined.
- Mineral wool panels with a measured air gap
- Fabric-wrapped absorbers colour-matched to the set
- Timber slat diffusers for larger rooms
- Track-mounted curtains for flexible spaces
Checking the result after treatment
After panels go up, we repeat the original measurements from the same positions with the same equipment. Comparing the two sets of readings is the only honest way to judge the work. Sometimes the improvement is large; sometimes one reading shows that a panel has been placed slightly off and needs moving.
We then listen on headphones and through the monitors in the control room, because a good number on a chart is no use if dialogue still sounds strained to the sound operator. A presenter reading a short script at normal pace gives us the final test.
The measurement files and a short written summary go to the client, with positions marked on a simple plan, so that a future engineer can see exactly what was done and why.
Keeping a simple record
Rooms change. A new set piece, a repainted wall or an extra rack alters how a space behaves. We encourage teams to keep the measurement files and repeat a quick check whenever the layout moves significantly.
A short log with the date, the room state and a few headline readings is enough. It turns acoustics from a one-off project into something a production team can maintain with confidence.
Good acoustic advice rests on measurement, not guesswork. A calibrated microphone, a few honest test signals, a careful look at background noise and sensible materials will tell you more about a studio than any impression on first entering it. If you want your room assessed, we will measure it, explain what the figures mean, and suggest only the treatment the results justify.
Priya Nair
Acoustics and Audio SpecialistPriya measures and treats studio spaces so dialogue is intelligible on air and in the control room.
Send us a message
- Phone
- 01305 842160
- By email
- [email protected]