Hello Mike!
Welcome to the forum!
Quote:
Originally Posted by mikefloutier  Firstly, can I clarify. Are you saying that the RMS figure is calculated by applying the corrected formula (sorry Andreas!) to a rolling window of the "Peak" (ie actual dbFS) signal. |
That's the usual way, yes. It needs some time and you can get that either through a bunch of succesive samples in digital domain, or through capasistance or mechanical ballistics of the VU meter needle, in analogue.
And don't be sorry, I'm very happy that someone spotted my fault! (Also a bit dissappointed that no one in here did it..) Had not done these calculations prior to writing that message. Just had an intuitive understanding of it. Have now done some manual calculations and finally learned the math way too.
Quote:
Originally Posted by mikefloutier 1. A completely steady signal would yield a figure for RMS that was the same as Peak whereas, |
If you mean a single repeating number when you say steady state, that's correct. It's a "sort of average" and an average of a single number is that number. Another way to think of it is that a steady state signal is a direct current. RMS is the DC equivalent of an AC. Since the signal you're testing is already a DC, there's no difference.
Quote:
Originally Posted by mikefloutier 2. When I did the "steady signal" experiment in practice with my DAW there was around a 7db difference between RMS & Peak. |
Now that's odd! One possibility is that it's the DC nature of the steady state signal being measured that messes with the
audio workstation. Many audio things remove or ignore DC by default. That could perhaps give rise to a short click at start/stop or similar that could give the measurement you got.
Andreas