What is in this article?:
- Monitor placement in broadcast studios
- A source of cancellation — the wall behind the monitors
- Sound coloration — the effect of early reflections
- Calibration — the method to ensure quality and consistency
Broadcasters have monitoring rooms of varying sizes and shapes. To achieve consistent quality in recording, live productions and on-air transmission, complete control of the audio reproduction quality in all facilities is essential. This implies careful audio monitor installation, systems calibration and setup of the audio monitors in the production spaces.
Radiation space — a changing monitor behavior
Why would the sound of a monitor change if located in different places in a room? Are corners not a good place for monitors?
First, at low frequencies — below around 200Hz — monitors and subwoofers radiate very long wavelengths and generate a certain volume of air flow. This air flow spreads into all directions much like a pulsating sphere. Hence, if one limits the space — by means of a wall of floor — while keeping the monitor sound output identical, the low frequency will be boosted in the newly limited space. (See Figure 1.)
As a consequence, placing the monitor on the wall, or very close to it, will contribute to an increase of low-frequency sound level. The measured response of the monitor will no longer be flat. Hence, to avoid having monitors sounding boomy or bass-heavy, which will fool the subjective sound perception, it is important to correct the monitor’s response to maintain a flat and balanced frequency response in the listening area.
It should be noted that at high frequencies, the monitor no longer radiates in all directions. As the frequency increases and the wavelength becomes shorter, the monitor radiation becomes increasingly more directional. So, placing the monitor on the wall does not contribute to an increase of high-frequency sound level.