The Amprobe SM-10-A Sound Meter has been designed to check compliance with safety regulations and perform acoustic analysis by safety engineers, health, industrial and safety offices as well as quality control. They use two different weighting filters required by the IEC651 and ANSI S1.4 Type 2 for audio filtering. The A weighting is for general noise sound level and the C weighting is for measuring sound level of acoustic material control in various environments (ie 94dB 1 kHz etc.)