How to Use an Anechoic Box

AEB

An anechoic box can be placed right next to the desk of the person in charge of research and development. Since its box has the same level of sound insulation performance as an anechoic chamber, it allows him/her to quickly check the correlation between its data and the master data acquired in the anechoic chamber.

Using an anechoic box in combination with an anechoic chamber may accelerate efficiency of research and development, while the acquired data in the low frequency range will be different, since the volume and the thickness of the sound absorption layer differ from those of the anechoic chamber. The difference of performance level calculated from the acquired data in an anechoic chamber can be used as an offset, which enables the data to correct the performance level measured in an anechoic box. Since no standards nor clear criteria are defined unlike an anechoic chamber, an anechoic box is suitable to be used for the ancillary and simple purpose.

How to use a sound level meter with an anechoic box (example)

• 1. set the microphone extension cable into the sound level meter
• 2. insert the extension cable through the cable port of the anechoic box and run it through
• 3. screw the lid of the cable port on to insulate the sound
• 4. set the microphone (sound receiving point) inside the anechoic box
• 5. place the measurement target under test (sound source) in the anechoic box
• 6. close the door and conduct an acoustic measurement from outside the anechoic box using a sound level meter

Unlike an anechoic chamber, a free sound field does not occur in an anechoic box. However, the sound insulation performance is equivalent to that of an anechoic chamber, so the background noise inside the box is at the same level as in an anechoic chamber. (i.e. a very quiet space). Therefore, it is possible to measure small sounds.

There is also another way of use to compare and correct the acoustic measurement data measured in an anechoic chamber and an anechoic box respectively.

Sonora offers suggestions on how to set up the measurement targets and the measuring instruments, as well as the selection of measuring instruments themselves, according to the measurement conditions.