What are sound level meter dB scales?
When measuring sound using a sound level meter, you have several types of decibels to choose from. All of them are based on the decibel sound pressure level. You could read dB in an octave band, for instance. Or you could select the filter scale for dB types A, B or C. These filters reduce the energy of primarily low frequency energy. Figure 4. Illustration of the A, B and C scales and the unfiltered, linear scale. From Quest Electronics Instructions for Model 1800 Sound Level Meter. So, if you are measuring a low frequency sound, like the bass sound from a stereo at 100 Hz, you will read 20 dB lower with the A filter setting selected on the sound level meter. So, as you can see, it does matter which type of decibel you use! That is one of my biggest pet peeves, it ranks right next to not specifying how far away one is from the sound source. (Duh, is it 100 dB A at the speaker, 3 inches from the speaker, 3 feet from the speaker ) The A, B and C scales have different uses. The A scale i
