anti noise theory

[Pounder2000]

just wondering if anyone has tried the same idea they use in some factories with massive machines that pump out the same frequencies over and over?

the idea is to have a speaker reproducing the same soundwaves only mirrored so that when the noise from the machine and the speaker meet they cancel eachother out.

i think this could be done to reduce if not cancel out fan noise.

all you would need is a mic, an amp and a speaker (right?) anyone got any ideas?

maybe someone could try it out and post the results.

(please dont flame me for being stupid if this is wrong. this is just me thinking after a long day at work.)

[cowanrg]

my friend actually had that same idea. i dont see why it wouldnt work. i wish i had some noise cancelling headhphones or something so i could try it out. it SHOULD work. let me know if you try it. im really curious.

maybe ill go out to best buy or something and get a pair, and test it out, then return em if they dont work ;-)

[typhoonmike]

Heh didn't they have an episode of the new Batman that had an evil villan with a item like that? Interesting idea.

[Kingslayer]

But I already use my speakers as "fan noise cancelling devices". I use them in conjunction with my volume knob.

Works great.

[KILLorBE]

Originally posted by Pounder2000
(please dont flame me for being stupid if this is wrong. this is just me thinking after a long day at work.)

Don't take this as a flame cuz it will work.(and your not stupid, there's only one guy here that's stupid and that's.....uuuhhh me :rolleyes: )

Problem #1 the mic (one that could do the job) would cost you about $200 (or more)

Problem #2 Get over problem #1 :D

Its just waaaayyy to expensive, you'll need very VERY good equipment to do that.

Sorry didn't want to burst your bubble.

[WyrmMaster]

You can buy noise cancelatin devices, im not sure how much, but i think only about $50. Spendy,but if it makes your PC virtually silent even with a 80mm delta...

[KILLorBE]

Originally posted by cowanrg
i wish i had some noise cancelling headhphones or something so i could try it out.
maybe ill go out to best buy or something and get a pair, and test it out, then return em if they dont work ;-)

They will work and they would cost you ~$110 w/o S&H (I'm sure you can find them for less), as the noise canceling headphones kill the background noise, they kill a lot if not all the game sound when playing a game.

There are NC Headsets that let you listen to music (or any other type of audio), but you could of course use regular headphones.

Originally posted by KILLorBE
Problem #1 the mic (one that could do the job) would cost you about $200 (or more)

Wrong, you won't need a full range mic, so a ~$25 mic will probably do the job.

I think the best way to go is:

Record the noise of the fans, get a sampler or something that lets you loop the sound/noise (Record and mirror it on your PC? ) and just play that (looped of course).
Guess that will work, but you're gonna need a extra pair of speakers and an Amp or a mixer (well only if you wanna play games or listen to some mp3s and a like)

Originally posted by KILLorBE
there's only one guy here that's stupid and that's.....uuuhhh me :rolleyes:

Yup, your right :D

[Pounder2000]

think im gonna give it a try because im waiting for my comair rotron fan to come, and i think i'll be needing this to cancel out the noise from that beast.

iv got a 300 Watt amp, a mixer and speaker spare, so in theory all i hav to do is record it, miror it and record it onto CD or sumthing and patch it through close it all up and it should be silent (right?) or hav i missed something?

honestly didnt think i'd get much response to this post, cheers ppl.

[KILLorBE]

Originally posted by Pounder2000
or hav i missed something?

Maybe a mic?

I did forget something, actually 2 things.

1 You might need to synchronize the sound (use the pause button).

2 Fans put out a pretty monotone (or whatever it's called) noise/sound, that's why I think it'll work.

I'm just guessing as I didn't try it myself, but this would be the easiest (and most important) cheapest way.

Cant think of a better (and cheap) way to do it.

Let us know if it works.

[SLuR]

It is a good idea
You would need to put the speakers near the fans thought or you will get constructive as well as destructive interference patterns as the sound waves travel different distances. Sound bouncing off the walls, celing and objects in the room will create a more complicated pattern of constructive and destructive spots.

Speaker placement would be no problem if u only care about noise cancelation where u sit when u useur computer.

[Pounder2000]

it sits at my feet so i could really do with this.

i just got my fan in the post (biggest thanks to Intraveinas) and i'l hav it in by Monday if i find time at the weekend.

should be able to set the sound canceler up by wednesday, i'l let you all know.

if anyone else wants to give it a go and tell us all i would be really interested to see if we get the same kind of results.

[Robbie]

higher freq are ALOT harder to cancel then lower ones. Ever wire the speakers in your car wrong? Notice how you can bearly feel or hear the BASS?? But the highs sound ok?!?!? Well the lower freq are canceling each other out, but the higher ones don't.

Hope this helps

Rob

[Slurgi]

higher freq are ALOT harder to cancel then lower ones. Ever wire the speakers in your car wrong? Notice how you can bearly feel or hear the BASS?? But the highs sound ok?!?!? Well the lower freq are canceling each other out, but the higher ones don't.

What would be the sound frequency of the fans?

I would assume it is low pitched, but this is judging solely by putting my ear next to my intake fan :)

[Coolio]

Originally posted by Slurgi


What would be the sound frequency of the fans?

I would assume it is low pitched, but this is judging solely by putting my ear next to my intake fan :)

I thought Deltas had a high pitched whine. Kinda like a blow dryer.

[Pounder2000]

yeah its a bass sound at the minute. dont think the high pitch frequencies will occur. they will be harder to cancel as the actual wavelength is shorter for them (i think thats right).

Also i think the effect i'm trying to create is known as a "standing wave"

[Intraveinous]

No problem on the fan, mate! Lemme know if it works as I still have my other one and it's loud as heck... running it at 7 volts is about the only way I can stand it as it draws too much current to put any rheostat I can find on it...
Slurgi, where in Iowa you from???
Peace
John

[Pounder2000]

been talkin to a friend of mine who gave me the heater matrix from a car he uses for spares and he thinks that he can get me a rheostat/pot that can take 20+ watts. this would be perfect i think.