I'm working with an application where I'd like to detect a short sound from a distance up to 100 m. An ultrasonic chirp has been unreliable so far. I was contemplating the use of the snap of an electrical arc spark (like a gas stove lighter), which ostensibly would produce a small shock wave that would not attenuate as quickly as a normal sound wave in air. Does anyone have experience with this and is there a reliable way to recognize this "snap" over other background sound?
Sparks like that are used in room acoustic scale modeling. They are not good at driving low frequency and mid frequency sound fields, and they are not particulaly omnidirectional.
Air absorption is high for high frequencies and it varies with the relative humidity. Dry air is more absoroptive.
A start gun will work nicely for the purpose, I think. It does take use of hearing protection and there should not be any listeners closer than say 50 m from it without protection, maybe even out to 100 m for safety.
An other option is to use an omnidirectional or a half sphjere speaker with sufficient power or make something like that from a PA setup and run fairly slow sweeps. Our strongest sources have an LwA of about 120 dB ish, but it is weakest in the lowest frequencies. These are made for sound insulation measurements from 50Hz - 5000Hz. Norsonic for sound insulation and B&K omni speaker for room acoustics. The omni setup is weaker.
A low background noise level is, of course, also useful.
I do have a lightning app on my phone using data for lightenings registered in a central or several around the country and possibly globe. I think these work on the electromagnetic (EMP) pulses generated. Sparks are plasma which generates light, but also radiowaves, long wavelength EM waves. I think it is easier to design something based on EM waves than sound for sparks.
There are systems used in weaponry for detection of positions of snipers and other shooting Based on acoustic detection. These algortims are probably not easy to get a hand on. They probaly rely on a rather strong signals, including knowledge of the time history of a shot from weapons. There is more than one incident.
DR DON!!
Please take a look at the following useful links:
https://hal.archives-ouvertes.fr/hal-00810828/document
Article Characteristics and application of laser-generated acoustic ...
DR Don--have a look at the following links:
Article Shock wave generated by high-energy electric spark discharge
and
Article On the characteristics of a spark generated shock wave
Hope this helps:
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