On Wednesday 12 December 2012 03:19:28 pm Rob Landry wrote: > My understanding is that dB is always a measure of power ratio. 10 dB down > means 1/10 the power.
NOT true ! A db is a ratio of magnitudes. Can be voltage, current, power, magnetic field strength, sound, lumens, whatever. Anything that has a magnitude. Could even be water pressure, though I know of no one who's ever used the terms that way. > For example, 1 volt RMS across 100 ohms is the same level as 1 volt across > 1,000 ohms, but the ratio between the two cases is 10 dB. Again, not the case. The voltage ratio is the voltage ratio, in this case 0 db. The power ratio in this case is 10 db. > Maybe it's time we actually start calling a volt a volt. And in too many cases, I wish we would !! Using terms not fully understood by the people involved leads to misunderstandings, and "truths" that are not. Too many assume that db means the same as voltage, when it's no such thing. -- Cowboy http://cowboy.cwf1.com _______________________________________________ Rivendell-dev mailing list [email protected] http://lists.rivendellaudio.org/mailman/listinfo/rivendell-dev
