I saw a posting which said add 6dB for a factor of 2. That is incorrect; when you are dealing with sound. My apologies to this poster; no disrespect intended.
When dealing with sound and power, add 3dB for a factor of two. A factor of two only works out to 6dB if you are dealing with voltage, field strength (and possibly some other measurements). There was a long thread which went into the gory mathematical details about a year ago. I'll spare everyone the details; but I'd be glad to explain to anyone who contacts me offline. For sound, the worst case would be to add 3dB for each shelf. However, in the real world, the noise probably won't all add together (there will be power/phase/frequency differences). I saw Paul Hare's response which said to add 13dB for 20 chassis. That "sounds" about right to me ;-) Chris Maxwell | Design Engineer - Optical Division email [email protected] | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ 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://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
