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Originally Posted by DanDan  If you stop a 63 Hz tone or third octave of pink suddenly, the waveform and energy content will be very different at each random stop. |
That could be, which is probably another reason REW uses a swept sine wave, in addition to a sine sweep being better than pink noise for frequency response too. When software sweeps a sine wave the identical signal is output every time. And a room should respond the same way every time too.
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Regarding the Non Linearity. That seems a bit deep, and Ethan can turn into a bit of a Terrier sometimes....:-)
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It's a fine line between being passionate and standing up for what you believe in, versus being an asshole. I try hard to stick to the former but I may not always succeed.
If anyone can show a room responding differently at different SPL levels, I'll be glad to change my position!
More on that: Earlier I said that nonlinearity adds distortion into the room, but I didn't explain why. Assuming at least one person here cares, I'm glad to explain.
Using a sine wave as an example, SPL is an average of all the points along the sine wave. A single sine wave at 100 dB SPL has a minimum (zero) and a maximum (about 1.4 times the average level an SPL meter would display). So a sine wave does not have a single level, but rather a
constantly changing level. Now, if you add a material into the room that "behaves" nonlinearly (whatever that means), as was suggested earlier for rockwool, that means the low-level portions of the wave will be affected differently than the high-level peaks. And if that's true the result would be distorted music with the inevitable added harmonics and IM products! And we all know that's not true.
--Ethan