Audio Engineering

Room Acoustics 843

25 dBA or less, which subjectively is very quiet. (The majority of domestic living rooms,
considered by their occupants to be quiet, generally measure 30–40 dBA.)

The background noise level in a studio is made up from a number of different sources and
components and for control purposes these may be split up into four basic categories:

● External airborne noise,

● External structure borne noise,

● Internally and locally generated noise,

● Internal noise transfer,

Each source of noise requires a slightly different approach in terms of its containment or
control.

Achieving low noise levels in modern studios is a complex and generally costly problem
but any short cuts or short circuits of the noise control measures will destroy the integrity
of the low noise countermeasures and allow noise into the studio.

10

20

30

40

50

60

70

80

90

31.5 63 125 250 500 1000 2000 4000 8000

Frequency (Hz)

Octave band sound pressure level dB ref 2

10

^5

N/m

2

70

65

60

55

50

45

40

35

30

25

20

15

NC

Figure 29.1 : Noise criterion (NC) curves.