CurtPalme.com Home Theater Forum

[damien55]

Hi,

My Barco 808 is currently sitting on a table in my living room between two couches. As I am renting the place there is no way I can fit it to the ceiling so I need to live with that noisy beast sitting next to me.

I did some research and apparently there is no quiet fan that could produce the pressure and airflow of the original NMB fans.
The common solution is to build a hush box but in my configuration this is not possible (too big, Housemates will not agree).

So I thought about a few other things that could be done and wanted to see with you if it was daft or not.

-1st option : Egg box foam on the inside of the covers. This should muffle the sound that comes from the chassis. Egg box foam in the Fan compartment at the back of the projector. Basically everywhere except from the back grille, the fans and the EHT Board. This should absorb some of the noise that reflects on the input PCB and the CPU case. A nice and big piece of foam on the wall 20cm behind the rear of the projector to prevent the sound from reflecting on the wall.

-2nd option : Ask NMB for modern quieter replacements. The original ones have been superseded by new models and might be quieter (Doubt it though).

-3rd option, change the Rubber mounts as the old ones are a bit dry and hard now.


So what do you think? Am I being stupid or would it be worth my time and money (foam is cheap after all and my time is cheap too)

Damien

[zGman]

Normally the noisiest fan on 808 is the one in front in the convergence tray.

It takes a fair amt of work to improve the airflow to the convergence amps
and reduce the front fan noise.

If the rear fans are really loud, you should check the voltage, normally it will
be about 7.5vdc. Otherwise there may be some issue with cooling.

G

[damien55]

The fans at the back are indeed the noisy ones in my case. I will check the voltage because to me they are going at the same speed all the time. So they may be running at max speed for no reason.

Thanks for your help

Damien

[AnalogRocks]

If you go with the foam do a flame test. Many types of foam will light up into a flash fire in an instant. I once had 30 hard drive boxes here with fitted foam. I did the fire test and immediately went and discarded them.

A few fan tips to quiet things down that I have learned from PC's.

If there's a grill in front of the fan it will be noisy. Remove the grill if you can. If you can't make a spacer so the fan sits further away from the grill.

Mount the fans with a gasket. I used silicone but an old mouse pad is perfect too.

Isolate the mounting screws. I use large cable ties and rubber grommets from the plumbing isle. You use the cable tie in place of the screws. One goes through the hole in the case ( with a grommet ) and the other zip tie you use it's end to secure the first one to the fan.

Sound deadening. If you have a panel that vibrates you can quiet it down with a commercial product such as dynamat or you can go get some plumbers putty ( buttle rubber ) and apply it to the panel that's vibrating.

[AnalogRocks]

If you go with the foam do a flame test. Many types of foam will light up into a flash fire in an instant. I once had 30 hard drive boxes here with fitted foam. I did the fire test and immediately went and discarded them.

A few fan tips to quiet things down that I have learned from PC's.

If there's a grill in front of the fan it will be noisy. Remove the grill if you can. If you can't make a spacer so the fan sits further away from the grill.

Mount the fans with a gasket. I used silicone but an old mouse pad is perfect too.

Isolate the mounting screws. I use large cable ties and rubber grommets from the plumbing isle. You use the cable tie in place of the screws. One goes through the hole in the case ( with a grommet ) and the other zip tie you use it's end to secure the first one to the fan.

Sound deadening. If you have a panel that vibrates you can quiet it down with a commercial product such as dynamat or you can go get some plumbers putty ( buttle rubber ) and apply it to the panel that's vibrating.

[Ile]

Egg foam made little improvement in my 801s. 808 have metal cover under plastic one so there's is not as much room for foam. By making all possible mods you still can't cut noise much, few db drop isn't probably enough for you.

How about coffee table hushbox? Those aren't that bad looking, not sure how effective those can be though.

[damien55]

Thanks AnalogRocks, I didn't even think about Fire Hazard. Will take that into account.

As for grilles and and fan mounts I think Barco has done a decent job as they are all mounted using "Rubber screws" and they are not again a grille. I need to see if moving the fans futher away from the frame would make things better but then I would have to build some kind of custom duct.

Damien

[zGman]

The fans' proximity to the card cage does cause more noise -
but it is a lot of work to fabricate extensions, and there is not
much room.

Replacing the rubber mounts will help a little.

G

[gjaky]

It might sound weird, but try headphones.
There are very good options to enjoy full spatial sound on a simple headphones, and it is supresses the noise very well.

[Person99]

I'm not sure why the hushbox is a no go. You can build it to be pretty much like a table between two chairs.

Secondly, why rule out ceiling mounting? It only takes 4 lag bolts to hang it. That is not much to patch up when you leave. I hung a couple barcos for years with just 4 lag bolts holding unistrut then cross pieces of unistrut which held the mount. It is not THAT hard to mount them and it is so much better--right now you are giving the PJ the best seat in the house!

[damien55]

Just checked the voltages on the fans and it is 7.2V only. I guess the problem is the fans themselves. The Projector has around 3000 hours on the clock so they should not be noisier than new ones.

[Revox]

In the moment i try to denoise a Barco Reality for a friend. The Idea was, that we use 4 Wire PWM Fans and control them via a Arduino Board (Atmega 25xx). The Special thing is, that we whant to implement a Mode in wich the Fans cool the PJ depending on the Moviesound.
So if there are loud Parts, the Fans run at fullspeed. In silent Movieparts, the Fans run down to a "minimum" (but this is not possible over a long period!!!).
Whe will see if this is a good idea!

The PJ temperature is measured via 15 Sensors, placed all over the unit, so whe can monitor the most important parts by testing our concept.

What i dont understand is, why Barco let every Fan blowing out! The ones in the front and in the Back. So we try out to change the blowing direction of the convergence Fans.

You can get much more silent fans than the original ones. The bearings and vibrations of newer Fans are much less than on those older ones. I think on industrial Products Noise was not a important factor.

[Elaine Benes]

You should check the components in your projector for heat and see if they are working properly. My 808s sits directly above my head less than 4 feet away and I can't hear it AT ALL. However, when it is inordinately hot, ie. if I've had it on for 3 days straight, then turn it off and right back on again, the fans run much, much faster and it is very loud.

Barco fans are very high quality, to state categorically that "bearings and vibrations of newer Fans are much less than on those older ones." is simply not true. Finding a replacement fan, with equal capabilities and quality would be prohibitively expensive and difficult. These aren't cheapo Chinese computer case fans, they were chosen to work effectively in the most difficult industrial environments for years and years and years. If your Barco is VERY loud, its because the temperatures INSIDE the projector dictate it.

[Revox]

When i look at my NMB Fans of the Marquee, they are well made! But the problems are the vibrations of the motor. The "glglglgl" is even louder when it is amplified by the blades. The NMBs on the LV Supply in Marquees are really terrible, but you are right, that those Fans withstand tests in industrial sourrounding. The Manufactures sacrifice a few db for a few thousand ours of lifetime. For example the "cheapo" Arctic cooling PWM fans do not vibrate when you runn them in your hand. The accelation of the fanblades seems to me very constant, i think the engeniers of the motorcontroll did a very good job. This Fan costs 5€.
That is something the old fans are not able to provide, none looked for silent fans and silent motor controls those times. The "chepo" PC marked opend this sector and the products are realy priceworthy. And for me the Fan must not run 20 000 ours, for me its ok, to change after 4000 ours to a new one.

I wonder about the fancontrol in this reality one: Why is there a special controlled fan for the horizontal deflection board. It is switched of when you start the PJ.
Is it to run the HDM at a constant temperature? The second thing is, how the Barco mentioned that the Fans are not running, there is no sense Pin.

[gjaky]

I think the fan speed could be judged by the supply current of the fan, however this is not the easiest way..

About fans: I doubt it that the evolution of fans has stopped in the past 10 years...

I saw (and heard) a Marquee LVPS with papst fans, and it was much quieter, then the other one, with NMBs. As I know the best fans are made by papst and sanyo-denki.

[Elaine Benes]

[AVphile]

Agreed. I tried "super-silent" low-rpm fans from Scythe and they did not move enough air (static pressue) so they ended up just as loud as stock NMB after warm-up. Then I tried giant "static-pressure" fans from Scythe and they sounded like a jet engine from the other side of the house. Went back to stock NMB with resistors (I know, they ultimately get loud after warm-up).

At this point I would like to try installing additional fans but I don't know where? Where is the temp sensor in the 800 chassis? It must be under a nice warm blanket of dust or something.