Why no Noise Cancellation in PC cases???

[Thingi]

The basic principle of active noise control is to create "anti-noise" in order to cancel the existing noise.

An active noise control system consists of a microphone that picks up the noise to be cancelled. This noise is then fed into a controller connected to a loudspeaker which creates a opposing waveform (180 degrees out of phase with the original wave and of the same magnitude).

Why has this not been looked into by the companies selling extreme air cooling? High end air cooling is just too loud, instead of having to resort to water (which still requires fans)?

thingi

 

[Crash893]

i asked about this a while back the consense was that anit noise oly works good in a small area if you used the anti nosie in your case it would be quite as long as your head was in the case

thats why most anti noise systems have headphones


as far as i know

 

[Annoyingrob]

Yes, you need a small area because the the cancellation wavelegnth has to exactly cancel out the original sound. For that to work, you would have to have an inverse sound eminating from the exact location as the original to block it, which just isn't possible. Alternatively, you could modify the wavelegnth to appear as the exact inverse as the original to a specific landing point (Like your ear), but that would require a lot of computing to ge the proper signal, and you would need a sensor, like a microphone at your ear anyway. And if you have already gone that far, might as well just stick the inverse source at your ear too.

Swimming in the deep end is very interesting

 

[Crash893]

not all that complicated they have a set at brookstone for liek 99bucks and you can use them as regular head phones

they work pretty well at getting rid of that background hum of a/c and other fans type stuff

 

[Annoyingrob]

There are even plans on the internet to make your own. It's simply in inverting op-amp.

 

[Crash893]

show me

 

[Annoyingrob]

http://www.headwize.com/projects/noise_prj.htm Here you go.

 

[Crash893]

sweet

 

[Scudrunr]

Sweet, I'll have to pass that link onto my brother. Hes a pilot. We tried to make something like that for an aux imput, but it went badly, maybe this will work better.