sound level meter problem

[Foufou]

When a measure the sound preasure in db using a sound level meter in my room, I found 40 dB.
I have an audiometer that generate sounds from 125 Hz to 8000Hz for intensities varying from -5 dB to 120 dB. I would like to measure these intensities using the sound level meter

for best mesurement of Sound Presure Level, should I obtain 0 dB (20µPa) in the absence of sounds?

how can I do this in my room specialy for low intensities -5 dB 0 dB 5 dB, knowing that in the absence of any sound the SPL in 40 dB ?

thanks

 

[FvM]

Hello,

Basically, that's not possible in this room. You need a more silent enviroment. I don't know the usual operating conditions for audiometers, e. g. how an ear specialist in a big city does it, if he has to build a dead room in his treatment facilities?

Some suppression of enviroment interferences could be achieved probably with special headphones.

Regards,
Frank

 

[laktronics]

Hi,
If you keep the mic input of your sound level meter as close as possible to the output of the audio meter, the sound level meter may show the reading correctly.
Regards,
Laktronics

 

[rikie_rizza]

Sound signal power is not accumulative, means that the pressure would not add more if we apply more sound. So, in this case, if the ambient sound is already 40dB, than you cannot measure sound less than that. Different from light, if you measure the ambient is about 1Cd, a 0,5Cd light can be measure by offset zero the ambient light. For sound, I'm sure there's an offset setting technique but...I don't know where.

Build a silencer for the room to create quieter room with no reverb.