Nois level inside Anechoic Chamber

[schola]

Dear sirs:

If an anechoic chamber was for sound isolation, inside noise level should be below 20 decibels.

Is the same requirement mandatory or advisable for RF anechoic chambers?

What is the noise level usually recommended?

Thanks

schola

 

[IceStationZebra]

First, I don't think of an anechoic chamber as being designed for "sound isolation". Instead think of it as minimizing reflected sound (which I admit could be seen as isolating the sound source from the reflected sound). Semi-anechoic chambers are designed to replicate the ideal free field site. A fully anechoic chamber is the same except in all 6 directions.

Second, you can't say that the ambient sound level in any anechoic chamber must be below 20dB. The minimum level required depends on the minimum level you wish to measure and what you level of certainty you want/need. It may also be dependent on some industry spec. If you are trying to measure a jet engine at 140dB does it really matter if the background is 20 or 30dB?

So in regard to you question:
- Do you need to meet some industry spec?
- Depends on the minimum level you wish to measure and what level of certainty you want/need. (which also drives the measurement devices)
- budget (as always!)

ISZ

 

[GregLocock]

20 dBA would be a ridiculous target if the cooling air and other services were operating at full capacity, for example, for a car. 50 dBA would be acceptable.



Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.