Noise Reduction On The Cheap

[james_bond_rulez]

i know the physics, i am just a bit overwhelmed...

I got an A in physics during high school and I took a few Uni physics courses so ya I know my material

[tesco]

Originally posted by james_bond_rulez@8 April 2004 - 22:08
i know the physics, i am just a bit overwhelmed...

I got an A in physics during high school and I took a few Uni physics courses so ya I know my material

hmm, i did good in the electrical physincs stuff of grade 9, but this year in grade 10 physics im just so overwhelmed...and we only started 2 days ago

[Skillian]

Flying Dutchman, thanks heaps for your help. I think I understand what you're saying. I've been away for a few days which is why I didn't reply sooner, but I will have a look through your ideas over the next couple of days and see what is feasible to implement.

As an aside, I got an 80mm CPU fan adapter on Friday and I haven't had a chance to properly test it out yet, though it seems to have reduced the sound a decent amount and dropped my load temps by about 5 degrees. The dominant sound from my rig now is a low whoosh from the 80mms, rather than the higher pitched whining sound from the 60mm. So some success already I am pleased to report.

[Skillian]

I had a play around last night:

At the moment I'm using side intake, rear exhaust and CPU and PSU fans. None of these are quiet fans. From what I understand, you are suggesting adding three more fans at front, top and exhaust, and disabling the side fan. Yesterday I moved the side fan to the front and temporarily closed all other holes and case temps increased by about 10 degrees. The posistion of the front fan doesn't allow enough in so I won't use that as my only intake fan. The side fan is necessary to allow fresh air into the case. I think the CPU and exhaust are pulling this air over the mobo so it does provide some cooling to the parts. The front intake would only cool the front devices like HDD and CD, and the air won't reach the back of the case.

Twisitng the grill on the PSU is a good idea, the grill design is slightly different to the example, but I think it will still get good results.

I will try the duct, though for this to work I would have to reverse the flow of the CPU fan. I think I will buy two low revving fans, one each for the CPU and the PSU, and check my temps with those flowing in both directions. I still don't know a CFM to be aiming for when buying a fan for the CPU, so I will have to see how it goes.

This way only involves me buying two slow revving case fans, rather than 4 or 5 which at £10+ a go could prove pricey.

Sorry for the windy post, this thread really must be boring for everyone in here!

[FlyingDutchman]

Originally posted by Skillian+12 April 2004 - 15:32--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Skillian &#064; 12 April 2004 - 15:32)</td></tr><tr><td id='QUOTE'>
I had a play around last night:
At the moment I&#39;m using side intake, rear exhaust and CPU and PSU fans. None of these are quiet fans. From what I understand, you are suggesting adding three more fans at front, top and exhaust, and disabling the side fan.
[/b]

Right &#33;

The idea is to establish a more efficient airflow for cooling.

Originally posted by Skillian@12 April 2004 - 15:32

Yesterday I moved the side fan to the front and temporarily closed all other holes and case temps increased by about 10 degrees. The posistion of the front fan doesn&#39;t allow enough in so I won&#39;t use that as my only intake fan.

Now you are telling me you mounted a 80 mm fan on a 120 mm grill. Did you tape the portion of the grill not covered by the fan? I fear NOT.
When not, air would be allowed to pass around the sides of the fan to the front, only to be recycled again. Please tell me you weren&#39;t THAT careless&#33;

Originally posted by Skillian@12 April 2004 - 15:32

The side fan is necessary to allow fresh air into the case.

I hope not, and hope to prove to you you don&#39;t need it.

Originally posted by Skillian@12 April 2004 - 15:32

I think the CPU and exhaust are pulling this air over the mobo so it does provide some cooling to the parts. The front intake would only cool the front devices like HDD and CD, and the air won&#39;t reach the back of the case.

Perhaps it helps when you change your point of view. Don&#39;t regard cooling as supplying cool air to hot parts. Look at it this way: cooling is "removing hot air from the case".

Originally posted by Skillian@12 April 2004 - 15:32

...
I will try the duct, though for this to work I would have to reverse the flow of the CPU fan. I think I will buy two low revving fans, one each for the CPU and the PSU, and check my temps with those flowing in both directions. I still don&#39;t know a CFM to be aiming for when buying a fan for the CPU, so I will have to see how it goes.

Now, when you do the "duct thing", imagine what will happen.
*- Hot air from the CPU is captured and expelled from the case immediately ----&#62;
*- Thus the CPU doesn&#39;t heat up the case anymore ----&#62;
*- The air in case will become cooler than it is now ----&#62;
*- The air to cool the CPU will be cooler than it is now ----&#62;
*- The CPU needs less air to be cooled ----&#62;
*- You can get by with less powerful fans ----&#62; noise reduction.

Originally posted by Skillian@12 April 2004 - 15:32

This way only involves me buying two slow revving case fans, rather than 4 or 5 which at

£10+ a go could prove pricey.

You can de-power existing fans by under-volting them.
A Zalman "Fan-mate" costs something like 5 pounds and is powerfull enough to regulate two medium speed fans (.5 Amps max)
Connecting two fans in series has them each operating at 6 volts and costs nothing.

<!--QuoteBegin-Skillian@12 April 2004 - 15:32

Sorry for the windy post, this thread really must be boring for everyone in here&#33;

[/quote]
The ones that are bored to death by this subject can skip it, and of course I hope to spread &#39;the gospel&#39; to more people than just you.
Air-cooling can be done so much better than it is usually done.

[Skillian]

I did block the air vents around the grill, along with any other holes behind the front bezel - only with sellotape but it seemed to be pretty airtight.

I still find it difficult to imagine efficient aircooling with only one intake fan and a very poorly placed one at that. Indeed my tests with it seem to suggest it is much less inefficient than my current set up.

This pic shows the ONLY vent at the front for air to get through to that front intake fan - with the USB wires in there it is close to useless.

[FlyingDutchman]

Originally posted by Skillian+12 April 2004 - 21:27--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Skillian &#064; 12 April 2004 - 21:27)</td></tr><tr><td id='QUOTE'>
I did block the air vents around the grill, along with any other holes behind the front bezel - only with sellotape but it seemed to be pretty airtight.
[/b]

Ok, you closed them. Glad you did.

Originally posted by Skillian@12 April 2004 - 21:27

I still find it difficult to imagine efficient aircooling with only one intake fan and a very poorly placed one at that. Indeed my tests with it seem to suggest it is much less inefficient than my current set up.

My current rig doesn&#39;t have an intake fan at all. Air flows in naturally to fill up the space left by the expelled air. So, you can get by without.

<!--QuoteBegin-Skillian@12 April 2004 - 21:27

This pic shows the ONLY vent at the front for air to get through to that front intake fan - with the USB wires in there it is close to useless.

[/quote]
It would be improved a little When you place the case a little higher. Some books perhaps?

When you find your PC gasping for air don&#39;t forget you can open up the slot-covers&#33;

[Skillian]

I&#39;ll have a further play around with the positions but so far my results are:

1 side intake, 1 rear exhaust - 30 under load
1 front intake, 1 rear exhaust - pushing 40 under load

sys temps, not CPU

It&#39;ll need a serious turnaround for me to switch that intake fan.

[FlyingDutchman]

Originally posted by Skillian@12 April 2004 - 22:07
I&#39;ll have a further play around with the positions but so far my results are:

1 side intake, 1 rear exhaust - 30 under load
1 front intake, 1 rear exhaust - pushing 40 under load

sys temps, not CPU

It&#39;ll need a serious turnaround for me to switch that intake fan.

Even 30 under load is too high, and of course you can&#39;t have a 40 degrees case temp when summer hasn&#39;t even arrived yet.
5 to 7 degrees over room temp is what I strive for.
But when you construct a duct we should see a marked improvement.

Man, I wished you were living close by, so I could lend you a hand.

[Skillian]

Originally posted by FlyingDutchman@12 April 2004 - 21:18
Man, I wished you were living close by, so I could lend you a hand.

Me too, perhaps you could bring your nibblers