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ParaMike

by FMMT666, published

ParaMike by FMMT666 Aug 9, 2012

Description

ParaMike, a functional and printable, parabolic microphone for kids and geeks.

Recent Comments

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An interference tube works fine but is less sensitive, on other side they have better overall response to all frequencies. Parabolic microphone are far more sensitive, but depending on the size of the paraboloid, the low frequencies response is bad. I've been experimenting with parabolic microphones and found out that most recordings don't require good response at low frequencies to obtain good results. You have to choose between high quality&low sensitivity (not that much) X lower quality&high sensitivity (really sensitive). With one of my microphones (34cm diameter) I've made recordings at 100m with great results! Shotgun microphones can be improved via high gain electronics, but the noise generated by the electronics will also increase, so parabolic microphone tend to be better for great distances, while shotgun mirophones should be used at short distances.

"Parabolic microphones are generally not used for high fidelity recording applications because dishes small enough to be portable have poor low frequency (bass) response. This is because, from the Rayleigh criterion, parabolic dishes can only focus waves with a wavelength much smaller than the diameter of their aperture. The wavelength of sound waves at the low end of human hearing (20 Hz) is about 17 metres (56 feet); focusing them would require a dish much larger than this. A typical parabolic microphone dish with a diameter of one metre would have little directivity for sound waves longer than 30 cm, corresponding to frequencies below 1 kHz.

A shotgun microphone may be used as an alternative for applications requiring high fidelity."

http://en.wikipedia.org/wiki/Parabolic_microphone

Wouldn't an interference-tube yield better results?

The finished product sort of reminds me of K9 from the Doctor Who series.

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License

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Instructions

The given STL files contain a very small, 125mm diameter parabolic mirror. It can be scaled (up) to any size. The handle, however, should not be scaled (unless you you know what you are doing)

Except for the "overview file", all parts inside the STL files are centered and directly printable.

Electronics can be found here: http://www.askrprojects.net/hardware/paramike/index.html

WHAT TO DO

  • print all parts
  • glue parabolic mirror sides together
  • Attach the parabolic mirror to the handle, using

Wouldn't an interference-tube yield better results?

An interference tube works fine but is less sensitive, on other side they have better overall response to all frequencies. Parabolic microphone are far more sensitive, but depending on the size of the paraboloid, the low frequencies response is bad. I've been experimenting with parabolic microphones and found out that most recordings don't require good response at low frequencies to obtain good results. You have to choose between high quality&low sensitivity (not that much) X lower quality&high sensitivity (really sensitive). With one of my microphones (34cm diameter) I've made recordings at 100m with great results! Shotgun microphones can be improved via high gain electronics, but the noise generated by the electronics will also increase, so parabolic microphone tend to be better for great distances, while shotgun mirophones should be used at short distances.

"Parabolic microphones are generally not used for high fidelity recording applications because dishes small enough to be portable have poor low frequency (bass) response. This is because, from the Rayleigh criterion, parabolic dishes can only focus waves with a wavelength much smaller than the diameter of their aperture. The wavelength of sound waves at the low end of human hearing (20 Hz) is about 17 metres (56 feet); focusing them would require a dish much larger than this. A typical parabolic microphone dish with a diameter of one metre would have little directivity for sound waves longer than 30 cm, corresponding to frequencies below 1 kHz.

A shotgun microphone may be used as an alternative for applications requiring high fidelity."

http://en.wikipedia.org/wiki/Parabolic_microphone

The finished product sort of reminds me of K9 from the Doctor Who series.

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