Higher pitches indeed are attenuated more quickly with distance than lower pitches. Whether one octave will make a big difference for audibility or not is a different matter.

Here's an online calculator to demonstrate. http://www.sengpielaudio.com/calculator-air.htm

Put in 440 Hz: dB attenuation per meter is 0.2. So if wife is 3m away, the air attenuation at that note is 0.6; not too much.

Put in 880 Hz: dB attenuation per meter is 0.4. Same 3m away, she's 1.2 dB lower where you stand than what she hears.

Put in 1320 Hz: dB attenuation per meter is 0.6, or 1.8 dB lower where you stand compared to what she hears.

2640 (upper range of flute notes, yes?) and the attenuation is 1.6 dB/meter. Now we're talking some real attenuation.

Those attenuations in the normal playing range really aren't that significant at the distances you are working with her.

John, you could also use some isolating in-ear monitors - they will help. Use one side in, one side just hanging around your neck.

Have you gone to see Marshall Chasin yet? He will have several, well informed potential solutions for you to try.

-Scott

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