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Which direction should I aim the fans I have on top of my Onkyo 805. I had them in exhaust mode(firing out the top in the back/middle right) with little results, it was cooler, but not significantly. Then, I switched the direction of the fans, now firing down and lo and behold the temps went from 59/53 over heavy usage(The Rock on BR at about -13 db) to 39/34 in less than a minute. All I did was flipped the fans over. BTW, I'm just using 2 old biscuit fans I ripped out of some old XBOX prototypes that never worked anyway.


Any danger in firing the fans down into the 805 chassis? dust?
 

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This may sound funny, put pantyhose are are a good way to filter out dust. Just cut them to size and tape or rubber band them to the fans.


They're free if you're married.
 

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Sweet, I'm not too concerned the dust, I mean, it's going to get dust in it anyway...any thought on the DANGER, er is it bad to fire the fans down...?
 

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Quote:
Originally Posted by Captain Slow /forum/post/12974814


This may sound funny, put pantyhose are are a good way to filter out dust. Just cut them to size and tape or rubber band them to the fans.


They're free if you're married.


Hahaha! That's a great idea. I'll try that later tonight as the filters I bought were WAY too restrictive. I'll also post my cooling solution which keeps my receiver EXTREMELY cool.
 

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I always thought pulling hot air out of boxes was the preferred direction. Anyway, increasing the air pressure inside a case should push air out through the vents. Seems it should would that way, anyway.


You could always buy one of those nifty (but pricey?) laser (infrared?) thermometers to check things out.
 

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Quote:
Originally Posted by MichaelJHuman /forum/post/12981892


I always thought pulling hot air out of boxes was the preferred direction. Anyway, increasing the air pressure inside a case should push air out through the vents. Seems it should would that way, anyway.


You could always buy one of those nifty (but pricey?) laser (infrared?) thermometers to check things out.

From what I've seen and read when building computers, ideally you'll want both solutions. You want the cool air to blow across the motherboard and the resulting warm air pulled out of the back. So I generally put 1 larger fan on the inside of the front of the tower and face it toward the back, then on the back and top I have fans pulling the air that just got heated flowing over the motherboard out of the case.


In this situation blowing at or across the board is probably fine because it is so well vented along its edges, but I would still consider using some sort of filter (nice pantyhose idea btw, haha) to ensure a cleaner, longer-lasting receiver.


-Daniel
 

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Quote:
Originally Posted by MichaelJHuman /forum/post/12981892


I always thought pulling hot air out of boxes was the preferred direction. Anyway, increasing the air pressure inside a case should push air out through the vents. Seems it should would that way, anyway.


You could always buy one of those nifty (but pricey?) laser (infrared?) thermometers to check things out.

Pulling the air out is a preferred way, however, that is only if the air is pulled from/through where you need it to be pulled from. In some cabinet situations, the air can be pulled around equipment instead of through it which may not cool as well. In these situations, a fan blowing on equipment can be better directed to components.


I have my cabinet setup with an intake fan on the bottom left and an exhaust fan on the top right. In between, there is a shelf which has 3" of clearance between the front and the glass. This helps with pulling air across the receiver and taking out the warm ambient air, but that's not all I have done. I also cut a hole in the middle of the shelf and directed a fan upwards through the bottom intake vents of the receiver. It is amazing how cool my receiver stays now.


Before the cooling, I just opened the door when I used the receiver. This still allowed the heat to collect and I was uncomfortable with it. Another thing I did was plug the fan controller/PSU into the back of the receiver so it comes on when the receiver is turned on. I used Yate Loon 120mm fans @7v so I cannot even hear them.


On the other door of the cabinet, I have the same intake and exhaust setup for the Xbox 360. While this kept it much cooler than just opening a door, it was still warmer than I really liked given the reliability of these consoles. I made a duct from the Xbox fans to the cabinet exhaust fan which now keeps the console very cool with the door closed... Most of all, I got rid of the noise!
 

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As promised... Please excuse the mess and the mess of wires... I'm waiting for my new fans to arrive from NexFan (not happening) so I haven't cleaned everything up yet.














Test fitting of a wall/duct to keep the heat from affecting the Xbox. It works well, but I want to make a nicer looking solution, however, the doors are closed 99% of the time, so you don't see anything anyway.

 

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The airflow coming out of a fan (the high-pressure side) is directional, while the airflow into it (the low-pressure side) is diffuse and non-directional. Therefore, having the fan blow air directly onto what needs cooling (e.g., the heat sink fins) is usually the more effective approach.
 

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Quote:
Originally Posted by mlobitz /forum/post/12974771


Which direction should I aim the fans I have on top of my Onkyo 805. I had them in exhaust mode(firing out the top in the back/middle right) with little results, it was cooler, but not significantly. Then, I switched the direction of the fans, now firing down and lo and behold the temps went from 59/53 over heavy usage(The Rock on BR at about -13 db) to 39/34 in less than a minute. All I did was flipped the fans over. BTW, I'm just using 2 old biscuit fans I ripped out of some old XBOX prototypes that never worked anyway.


Any danger in firing the fans down into the 805 chassis? dust?

Are you reading this immediate 10 C temperature drop where the air is now exhausting from the cabinet? Or are you just taking both reading at the top of your cabinet (or maybe over the top of your receiver)?


I would think that the only correct way to calculate the effectiveness of your cooling setup would be to measure the exhaust temp and subtract the input temp. You could then directly calculate the amount of heat you are extracting from the system. It really sounds like you are not measuring the delta-temperature (dt) and could be leaving some hot-spots within your other components.


The most effective way to cool your rack is to have enough exhaust at the top of your cabinet; there realy isn't a need to push air into the bottom, unless your cabinet is not sealed very well and you want to make sure your system is getting some cool air circulating around the lower components.


Joe
 

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After looking at your setup(yamahaSHO)I think my setup with only 3 inch's at the top and wide open in back,front and both sides should be fine where is it that 705 gets the hottest or would my best bet would be to get the 605.
 

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Here's a picture of the two fans I added behind my 805, blowing diagonally across the unit. I only have 1.5" clearance above the receiver, though essentially open on all other sides. The fans don't have a ton of airflow (as seen in reviews at Newegg, see below), but they do a good job of clearing out the air above the unit. As a result, the receiver I would describe as cold in normal use, and sometimes barely warm after a high volume action movie. The fans are only $6.49 each and are totally silent. I can't hear them at all, even sitting directly in front of the receiver in a dead quiet room. I was hoping they'd help heat the room, but the air I can feel coming to the front isn't that warm.



The fans:

http://www.newegg.com/Product/Produc...82E16811999199


 
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