DIY parabolic reflector microphone (1 Viewer)

[Jaysan]

Hi. I have been thinking of sound recording for some time, but being the person I am, want make my own DIY microphone (ideally a parabolic reflector type). Does any one know where I can get this info?

Thanks,
Jaysan

 

[chrisij]

Hi. There's some info here, including a link to instructions for a DIY mike (but not a parabolic reflector).
http://www.wildlife-sound.org/equipment/newcomersguide/microphones.html

Chris

 

[GrahameNZ]

Hi Jaysan
A bit of theory
http://www.wildlife-sound.org/equipment/stereo_parabol/index.html
Some ideas
http://www.wildlife-sound.org/equipment/technote/micdesigns/index.html
And a cheepie reflector
http://www.bambooturtle.us/ParabolicMicrophone.html
Also wok lids and metal bowls etc can be used, tad heavier though.
Have Fun

 

[Jaysan]

Thanks Chris and Grahame. Thought there were no responses after a few days and gave up checking.

The bambooturtle website is great. Just what I needed.
Does any one know why the minimum dia should be >50 Cm.

Thanks again,
Jaysan

 

[ermine]

I've used a CJ Wildbird squirrelguard as a reflector, which is nice as you can see through the dish.

> Does any one know why the minimum dia should be >50 Cm.

the aperture of the dish determines the frequency response. All dishes focus sharper as the frequency rises, but to a first approximation once the dish width is less than the wavelenth of sound the LF response drops away massively as the sound simply bends round the dish (massively simplified)

sound has a speed of 330 m/s in air at room temp and 1atm pressure. So a wavelenth of 0.5m correspods to a LF cutoff of 330/0.5 ~ 700Hz. Purists will argue that sound waves are longitudinal and not transverse so the result is more complex. But 0.5m is sort of okay for birds unless you are after owls