Ideas Ideas Ideas...

Here's another idea that I've been trying to play with lately.

I've been looking into noise cancelling technology. However they only seem to work on headphones for the moment. I'd like to be able to attach these to the likes of fans where there's a low frequency hum. Noise cancelling only really works for low frequency waves as it is able to reproduce the opposing wave to cancel it.

Just as a quick physics mention here. Waves work in peaks and troughs (they go up and down). To cancel a wave, you must recreate each peak's or trough's exact opposite. This opposing wave must match the original's wave amplitude and wavelength. That's the basics, don't want to go into too much detail here.

Anyway, my idea is based upon PC cooling fans and trying to eliminate the noise of them completely. To build it, I would get one small microphone pointing away from the fan. I may need to add multiple microphones around the fan for this to work completely. Then using a speaker alongside the fan and connecting circuitry between the microphones and speaker we can then produce it's inverted wave.

Unfortunately this is a slightly difficult task. Waves do not just travel in the one direction, they radiate in every direction and this is where the problem lies.
Hopefully, because I just want to cut out the noise of fans specifically, I can achieve this goal without having to do too much work on it.