TV studios
Television studio: ducts, air noise and lighting heat
The ambient microphone picks up everything: the whistle of a diffuser, the knock of a damper and the hum of a fan working hard against the heat of the lights.
By Limpieza de Ductos Panamá
Studio ducts make noise for three causes that are checked in order: air moving too fast through diffusers or narrow sections, loose parts that rattle with the airflow and a system forced to run flat out by the heat of the lighting. A duct with dust or misadjusted dampers makes all three worse. The camera inspection and the diffuser check are done between recordings, without shutting off the air during the show.
Air noise: whistles and rattles
Duct noise comes in two families. The first is flow noise: air whistles when it passes through a small opening at high speed, and that opening can be a diffuser with its blades nearly closed, a half open damper or a section where accumulated dust reduced the free area. The second is mechanical noise: a damper with a loose shaft, an unbraced sheet of duct that drums, a poorly seated filter that knocks against its frame or the vibration of the unit carried along a rigid duct with no flexible joint.
Telling them apart is simple with the studio silent: flow noise changes when the diffuser blades are moved or the fan speed is reduced, and mechanical noise stays the same or comes and goes at intervals. That test is done in a gap between recordings and guides the whole review that follows.
Lighting heat and airflow
A lit set is a heat source concentrated in a few square meters, under a lighting grid and with people who cannot sweat on camera. To compensate, the air system runs at its maximum flow, and at maximum flow everything sounds louder: diffusers whistle, sheets rattle and the fan hums. If the filter or the coil are loaded on top of that, the unit pushes against more resistance and the noise rises without the temperature dropping. In a studio with LED lighting the heat is lower, but the airflow stays high because of occupancy and electronics.
To coordinate a visit related to tV studios, Climatiza answers inquiries and confirms availability according to the schedule of the place.
| Symptom during recording | Likely cause | What is checked |
|---|---|---|
| Constant whistle at one diffuser | Closed blades or free area reduced by dust | Blade position, camera in the branch |
| Knock or rattle at intervals | Loose damper or unbraced sheet | Damper shafts, long unsupported runs |
| Low hum rising with the lights | Unit at full load against a dirty filter or coil | Filter, coil, flexible connector of the unit |
| Noise only in one area of the set | Damaged diffuser or obstructed section | That diffuser and the section feeding it |
What to check in the set diffusers
The set diffusers are the last piece of the system and the closest to the microphone. They are checked one by one with the air running, noting which ones sound and which do not, and then the camera is run through the branch of each noisy diffuser to see whether there is dust, loose insulation or some object left behind during a set remodel.
- Diffuser blades evenly open, with no single narrow slot.
- Fixing screws tight and frame with no play against the ceiling.
- Visible dust on the blades or in the neck of the diffuser.
- Branch balancing damper with a firm shaft and a marked position.
- Internal insulation of the branch intact, with no loose pieces fluttering.
- Flexible connector between the unit and the main duct in good condition.
The ASHRAE 180 standard for inspection and maintenance of commercial HVAC systems includes the review of ducts, dampers and diffusers among the tasks a building should document. In a studio that documentation has an extra use: when production complains about a new noise, the record says what was fine last time and shortens the search.
Working between recordings
A television studio does not shut down to check ducts, but it has gaps: the set change, the lighting rigging block and the days without production. The review is spread across those gaps and split into two kinds of task. The noisy ones, such as opening access panels or running the camera, go in the long gaps. The quiet ones, such as listening to diffusers or reading the filter pressure drop, fit into a set change.
- Listening test with the set silent. Each noisy diffuser is identified and it is noted whether the noise changes when the blades are moved.
- Filter and coil in the next short gap. A loaded filter explains much of the hum. It is photographed and changed if due.
- Camera and adjustments in the long gap. Noisy branches, dampers and flexible connector. Whatever needs cleaning is decided with the criteria that separate cleaning from just adjusting.
- Check with the lights on. The listening test is repeated with the full grid on, because the noise that matters is the one during recording.
Report for production and engineering
In a channel there are two readers with different interests. Production wants to know whether the set will be silent on recording day. Engineering wants to know what was touched, in which unit and with what result. The report is written on two pages: the first, a plan of the set with each diffuser marked as silent, corrected or pending. The second, per unit, with photos of filter, coil, dampers and camera, and the adjustments made.
The EPA notes that duct cleaning has not been shown to prevent health problems, and in a studio that promise is not needed either: the result is measured by ear and with the set thermometer. This routine resembles that of a room with many workstations, equipment running and air at full flow and, in the newsroom offices of the channel, that of an office floor that depends on the building system. To spread attention across several sets, the planner that ranks priority by use and signs helps.
More about the inspection and cleaning service that applies these criteria is on the Climatiza duct cleaning page and on the Climatiza home page.
Sources
On this site
- Call centersHow the work is organized in this sector
- Offices and corporate towersA neighboring sector
- Camera inspectionThe real condition before deciding
Climatiza and Radar Panamá
Frequently asked questions
Does lowering the fan speed remove the noise?
It reduces flow noise, but also the airflow, and the set heats up with the lights on. Before lowering the speed it makes sense to recover airflow by cleaning the filter and coil and opening the diffuser blades that were nearly closed.
Can dust in the duct make noise?
Yes, indirectly. Dust reduces the free area at necks and dampers, and the air passes faster through the remaining gap, which produces a whistle. It also loosens pieces of insulation that flutter in the branch. The camera confirms it.
Does the air have to be off during recording?
It should not be necessary. If the only way to record in silence is to shut off the air, the system has a speed, loose part or load problem that is corrected in the gaps between recordings, not during the show.
What about control rooms and editing suites?
They have equipment generating heat and people listening closely, so the noise is noticed just the same. They are checked with the same listening test, but their diffusers are usually few and the work fits in a short gap.
Keep reading
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- info@climatizapanama.com
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