AVS Forum banner
Status
Not open for further replies.
1 - 13 of 13 Posts

·
Preditor
Joined
·
1,510 Posts
Discussion Starter · #1 ·
Just curious if anyone has thought of (or in fact done so) replaced the fans in the JVC D-ILA units with quieter fans?


I see these kinds of discussions in the HTPC groups so wondered if anyone tried it with the projectors?


-Brian




------------------

*always looking for Hi-Vision laserdiscs*
 

·
Registered
Joined
·
4,720 Posts
Brian,


What makes the D-ILA noisy is the sound of the air flow.

But with the JVC's Xenon arc-lamps - you need that degree

of air flow for adequate cooling. The D-ILA fans, are

not intrinsically noisy - it's just that they have a more

difficult job to do relative to other projectors that use

cooler lamp technology like UHP.


It's not all bad - the D-ILA's high color temperature is

what gives you the rich colors that the JVCs are noted for.


When you put a D-ILA in a hushbox - the hush box has a

cooling system to exhaust the cooling air. However, you

can exhaust the cooling air somewhere else beside the room

that you are watching the movie in - or you provide the

box with a large exhaust port area - like the multiple

exhausts of a Whisperflow. The greater area means you can

maintain the same mass flow at a lower air velocity.


[You could design a projector with the higher area / lower

velocity - if you made the projector itself almost as big

as a Whisperflow. ]


Unfortunately - in the physics of projectors like elsewhere;

there's no free lunch.


Dr. Gregory Greenman

Physicist
 

·
Preditor
Joined
·
1,510 Posts
Discussion Starter · #6 ·
I do have a hush box, and it has cut noise by 45%, but I want to cut noise down to nothing. My box is 1/8 thick oak, lined with 6.5mm neoprene. Guess I need to add some foam next.


I have both exhausts of the D-ILA hooked up to flexible dryer vents that output into my attic (so no cooling issues with the D-ILA or hushbox).


I see some high output but quieter fans for PC's so wondered if this may do the trick.


-Brian


------------------

*always looking for Hi-Vision laserdiscs*
 

·
Registered
Joined
·
4,720 Posts
Brian,


Exactly - you moved the noise problem to the attic - where

it isn't a problem. The dryer vent hose also has a larger

cross sectional area than the outlet on the projector.


Therefore, you can have a lower air velocity, and still

handle the mass flow rate of cooling air out of the JVC.


If you went up into the attic and listened at the dryer

vent hose - you'd see you still have a noise issue - it's

just that you've moved it to somewhere you don't care about.


PCs don't have components that operate at Xenon arc-lamp

temperatures. The cooling requirements for the D-ILA are

much more challenging. Hold your hand near the exhaust

fan for your computer - try to feel the flow, and feel the

heat. Now put you hand near the exhaust of the D-ILA - and

you certainly do feel both the flow and the heat.


Dr. Gregory Greenman

Physicist
 

·
Registered
Joined
·
159 Posts
One of the dealers in San Jose area does this. I dropped by his store about a year ago and he said that he doesn't sell the stock G15 without changing the fans because it was ooo loud.


- Chi
 

·
Registered
Joined
·
763 Posts
Brian:


We had the same issue. After installing the hush box we still could hear the fans. So , I think mark or Rich Peterson experimented with acoutical foam, lining all the inside surfaces of the hish box and also installing an optical clear panel (Edmonds optical glass I think) over the lens to completely seal the box.


This now has dropped the noise level significantly. I can hear it ever so faintly in a completely quiet passage but I have to really work at it to do so.


Chuck
 

·
Registered
Joined
·
1,679 Posts
Viking2000,


Watercooling is a solution for situations where you need extreme cooling without the associated problems of airflow. Instead you have other issues like condensation, tube and waterblock integrity, pump noise, radiator cooling (usually using fans), bacterial blockage, cleaning/draining the system and redundancy. That doesn't even bring into if you start using thermoelectric coolers like peltiers. You're also faced with how to mount the waterblock. I don't know if the lamps in D-ILAs or other projectors have heatsinks or not - if they don't the waterblock is going to be a problem. I've tried most cooling solutions including TECs, water cooling and air based. I would only recommend extreme cooling for situations where there's absolutely no way of getting around it as the result of a failing cooling system can be catastrophic. I'm perfectly willing to risk a $250 CPU+motherboard - no way I'd do the same with a multi-thousand dollar d-ila.


Before going that way there's a number of things you can do with fan based cooling:


- replace the fans with quieter ones that can still output the necessary airflow

- reduce the voltage going to the fan if it's overdimensioned

- if there's a grill in the way remove it - it restricts airflow slightly and will emphasize the noise more

- change the mounting of the fans so that the fan doesn't create vibration noise. I've always been a fan of doublesided tape for this

- hushbox <- of all the most effective. Properly dampened you won't hear the projector at all


------------------

/frode


[This message has been edited by Frode (edited 07-17-2001).]
 
1 - 13 of 13 Posts
Status
Not open for further replies.
Top