Rob, An A-weighted sound is a measurement that applies the ANSI A filter to the raw data. The purpose of this filter is to raise some bands and lower others a few dB so that it sounds even across the range to the human ear. The octave band adjustments are below (from ISO 7779:1999)
Hz dB 125 – 16.1 250 – 8.6 500 – 3.2 1k 0.0 2k 1.2 4k 1.0 8k – 1.1 16k – 6.6 These defined adjustments to the octave-bands and third-octave bands are in Tables 2 and 3 of ISO 7779:1999. BTW, this is typically a setting on the measurement device. Hope this helps, Sam --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.651 / Virus Database: 417 - Release Date: 4/5/2004 This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
