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Mars2020 landing cameras
Gerald
post Aug 28 2016, 12:34 PM
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I don't think, that sound attenuation poses any significant issue on Mars on the meter scale, especially when relative humidity is very low.
With this calclulator for atmospheric absorption, for sound of 1000 Hz, I get
0.014 dB / m for 103 kPa at 0C with 10% relative humidity, and
0.0255 dB / m for 0.6 kPa at -20C with 1% relative humidity.

Above 10 kHz, it may be going to become an issue on the meter scale.

The microphone membrane, however, might be required to deal with reduced sound intensity, since the low-pressure atmosphere transports less sound energy for the same amplitude.
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rlorenz
post Oct 12 2016, 05:33 PM
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QUOTE (Gerald @ Aug 28 2016, 07:34 AM) *
I don't think, that sound attenuation poses any significant issue on Mars on the meter scale,
The microphone membrane, however, might be required to deal with reduced
since the low-pressure atmosphere transports less sound energy for the same amplitude.


Yes, 6mb CO2 conveys sound quite happily over distances of a few meters. Here is some music played ('quite loud' in 1 bar air, but considerably
quieter here at 6mb simply because a loudspeaker diaphragm displacement at a given speed produces a lower sound pressure level simply because the
air density is lower, as you note). The sound is a bit distorted (ethereal, dare I say..?) because of reverberation/multipath between the parallel
metal walls of the chamber (these were tests I did a couple of weeks ago at the Mars Environment simulation chamber in Aarhus, Denmark).
There's also a lot of plant noise (electrical, rather than vibration/acoustic)

http://www.lpl.arizona.edu/~rlorenz/oxygene_on_Mars.mp3

More details to be presented at the Mars Atmosphere workshop in Granada in January

Ralph Lorenz
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