anti-noise to make PCs quiet

[VJ]

http://tv.ksl.com/index.php?nid=5&sid=81082

Their noise-control unit consists of four tiny loudspeakers and microphones built into the case around a fan.

The four microphones measure the fan's noises and signal a tiny microprocessor that drives the speakers, which make sound waves precisely canceling out the sound waves of the rotating fan blades. From the speakers come a sound pressure inverse to the pressure made by the fan, Sommerfeldt said.

Now this sounds interesting... (pun intended, ok, bad pun )


Jörg

[DukeP]

Works, but is prone to interferrence.

Its a nasty cure, tho - use more energy to suppress noise made from waisting energy...

Saw/heard it once at a car show.

My old Atari Falcon could do it, by using its dsp. Had some nice and funny tricks.


~~DukeP~~

[SpiralDragon]

heh... other wise know as phase inversion.... can be nasty when you have a muliti mike setup on stage and sudenly you cant hear somethings are miced..... its also a method used to cut out noise from a recording... one mic is put in the oposit direction of what your are picking up (actual depends on case) then you either invert the cables on that mike or do it in the post... end result.. noise cancelation

[Jammrock]

It would be easier just to make a fanless computer and use a silent HDD.

[Kurt]

Originally posted by DukeP
Works, but is prone to interferrence.

Its a nasty cure, tho - use more energy to suppress noise made from waisting energy...

Saw/heard it once at a car show.

My old Atari Falcon could do it, by using its dsp. Had some nice and funny tricks.


~~DukeP~~

OMG you had a Falcon?? I never could put my hands on one here! Selling it? j/k

[Wombat]

They've been working on anti-noise for PCs for years. Old news, and it's not there yet.

[Greebe]

Originally posted by Wombat
They've been working on anti-noise for PCs for years. Old news, and it's not there yet.

I'll second that. It'll not only be expensive but won't be anymore effective than reducing noise more than 3-6dB.


Spira it's significantly more involved than simple phase inversion.