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Non-surgical solutions to reduce projector noise without going full hush box

1360 Views 24 Replies 12 Participants Last post by PotentialProjectorBuyer, 4 d ago

NOAMattD

Discussion Starter · 7 d ago (Edited)

Some chatter in the BenQ HT2060 / HT4550i thread regarding projector noise got me looking around to see how one could potentially reduce projector fan (and now XPR) noise without building a hush box or niche, and without opening the precious up to perform fan surgery.

Share your solutions or ideas! This is AVS so nothing is too dumb, ugly, or convoluted as long as it's effective! We'll add the WAF/PAF/SAF/HAF later!

Posting this in the $3k and under subforum just because the pricier options like your Epsons on up seem to be naturally very quiet as per test results.

There aren't a great deal of current threads on this topic on AVS right now and a lot of the older ones no longer have their images available.

Anyways to start off here is my situation. It is absolutely one of, if not THE, worst possible configurations you could ask for in a dedicated media room: A one-way vault with a huge WEST-FACING window on the back wall opposite the screen, subjecting me to both direct sunlight AND more or less eliminating any ability to treat the back wall acoustically (separate topic). Oh, and no good option for building a shelf either (I could, but then I have no way to do a shade).

Making matters worse is that to the right of the room (where I took the picture) is the full glass front door. That's getting replaced this summer with a half-glass model that's more noise and energy efficient. Small victories.

(please ignore my ghetto temporary shade)

Wood Shade Comfort Building Tints and shades

that projector is a venerable BenQ TH670 I got refurbished 5 years ago for a birthday party. it's held up quite well with only one bulb replacement and now a very minor dust blob I can only see in pitch black scenes. But I am ready for an upgrade and heavily considering the HT4550i. Hence, this thread. More on the next post.

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NOAMattD

Discussion Starter · #2 · 7 d ago

So on to solutions. I can try and archive them here if anyone posts and season with keywords that'll help future searches.

My first idea, for mine, was to just velcro up like a 2' x 2' acoustic foam panel or something directly to the bottom of the projector to block some of the higher-frequency fan noise without restricting airflow at all. It would look absolutely stupid but maybe it'll work. I plan to try it at some point when I can.

This guy came up with an effective solution that cost exactly zero USD. This is what I'd consider the extreme functional end of the "functional - attractive" spectrum.

robbyc30

· #3 · 7 d ago

For any type of enclosure where you’re adding length and turns to the air path, you need to add fans. The internal fans are not designed to deal with all the added restrictions to the air path, and the pj will overheat. Depending on the pj and the enclosure design, it might not be enough to shut down the pj, but long term heat damage is probable.

Reactions: 1

PixelPusher15

· #4 · 7 d ago

@SirMaster wanna share your approach?

SirMaster

· #5 · 7 d ago

IMO most of the loudness comes from your ear being able to directly hear into some fan grill or sound bouncing off a close by hard surface into the fan grill.

So IMO you can just build some barrier around a part of the projector to put a solid piece of wood and ideally add some foam to the wood to block the direct sound between the projector noise source and your ear.

This can cut down the sound quite noticeably and shouldn't have concerns about cooling.

Some pics here of what I did to my projector.

http://imgur.com/a/cYq6461

Annoying fan noise in high lamp since sitting directly underneath, as a vast majority of the sound comes from the front side to the left of the lens and your ear can hear directly into that fan opening.

So I surround the noise source from below where your ear is, and also absorb a bit of the ceiling reflected sound as well and it sounds much quieter after.

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SirMaster

· #6 · 7 d ago

To add another idea, I briefly had an NZ8, and even thought the chassis was the same as the NX5, all the noise came out the back. Different internal design due to laser vs lamp.

Anyways, I had already started formulating my idea for how to quiet that NZ8 down in that mounting position, and what I would have done had I kept the NZ8 was build essentially a "wall" around the projector with a bottom on it, but open from the sides and top. Maybe even partially closed on the sides towards the bottom if the wider seats could "hear" into the sides too easily.

Rectangle Font Parallel Diagram Drawing

So, very different design than the NX5, but same overall concept.

And I would not be against adding some very quiet computer cooling fans to move air into the tighter spaces I have created just to keep it moving a bit.

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RayGuy

· #7 · 7 d ago

Clearly, this needs a Klippel solution. That way you will know the exact frequencies you need to address and their dispersion pattern around the projector. Maybe you can talk Erin into doing it for you?

Reactions: 1

DavidK442

· #8 · 7 d ago

Desperate times call for desperate measures.
If your projector mount is stout enough I would attempt to built a lightweight foam lined box using 1/4 plywood then hang the entire thing from your mount. Drill precision holes in the top of the box to act as a mounting plate for your projector. Use longer bolts and spacers to account for a layer of foam insulation. Space the mount's arms so that you can bolt through the top of the box while the projector is installed. If you need to enclose 5 sides to adequately control sound then the box will need to be quite wide for ventilation. You might find that having a top, back and bottom is sufficient in which case the box can be much smaller with perhaps ready-rod at the two front corners holding the bottom on.
I would agree that you are dealing with the worse case situation there.
I like your terms of engagement "Share your solutions or ideas! This is AVS so nothing is too dumb, ugly, or convoluted as long as it's effective! We'll add the WAF/PAF/SAF/HAF later!"

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Sid3Effect

· #9 · 7 d ago

5

My projector is about 4 feet above my head. The XPR noise was driving me crazy not so much the fans. My solution was to use a wall mounted server cabinet. XPR is mostly caused by vibrations/resonance so the best material to use is rubber. Foam does nothing. I lined my cabinet with Alubutyl. The fan noise is about the same in volume because the heat needs to be removed but it is a much nicer deeper fan noise that 140 mm fans make rather than the annoying higher pitched noise that smaller fans make. Noise is now somewhere in between Eco and Smart Eco with greatly reduced XPR so I am happier.

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Rectangle Audio equipment Gadget Gas Electronic device

Ventilation fan Gadget Output device Gas Audio equipment

Circuit component Digital camera Cameras & optics Camera Gadget

Fixture Building Wood Automotive exterior Composite material

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Daboyle82

· #10 · 7 d ago (Edited)

do a test first- buy one of these, then hang it with duct tape from the top of PJ mount to see if the noise levels improve. My guess is it will substantially

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NOAMattD

Discussion Starter · #11 · 7 d ago

Great responses so far.

SirMaster said:
IMO most of the loudness comes from your ear being able to directly hear into some fan grill or sound bouncing off a close by hard surface into the fan grill.

So IMO you can just build some barrier around a part of the projector to put a solid piece of wood and ideally add some foam to the wood to block the direct sound between the projector noise source and your ear.

This can cut down the sound quite noticeably and shouldn't have concerns about cooling.

Some pics here of what I did to my projector.

Annoying fan noise in high lamp since sitting directly underneath, as a vast majority of the sound comes from the front side to the left of the lens and your ear can hear directly into that fan opening.

So I surround the noise source from below where your ear is, and also absorb a bit of the ceiling reflected sound as well and it sounds much quieter after.

That's mostly along my lines of thinking. Physical barrier of some sort between ears and source of the noise is the top factor.

RayGuy said:
Clearly, this needs a Klippel solution. That way you will know the exact frequencies you need to address and their dispersion pattern around the projector. Maybe you can talk Erin into doing it for you?

Erin, Amir, and anyone else with a Klippel can come to my theater and borrow whatever they want to measure LOL

Sid3Effect said:
My projector is about 4 feet above my head. The XPR noise was driving me crazy not so much the fans. My solution was to use a wall mounted server cabinet. XPR is mostly caused by vibrations/resonance so the best material to use is rubber. Foam does nothing. I lined my cabinet with Alubutyl. The fan noise is about the same in volume because the heat needs to be removed but it is a much nicer deeper fan noise that 140 mm fans make rather than the annoying higher pitched noise that smaller fans make. Noise is now somewhere in between Eco and Smart Eco with greatly reduced XPR so I am happier.

So that's interesting. XPR noise is something I'm worried about looking at the BenQs. Mine has served me well so they have a lot of cred with me right now in terms of durability and reliability. For a ceiling mount you're suggesting some kind of rubber dampening agent, like rubber washers on mounting bolts, or even a rubber sheet contacting the body of the projector housing reduces XPR noise?

Daboyle82 said:
do a test first- buy one of these, then hang it with duct tape from the top of PJ mount to see if the noise levels improve. My guess is it will substantially

Thinking you forgot a link there bro but if it involves duct tape it must have potential.

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bud16415

· #12 · 7 d ago

Like a lot of people in the <3000 forum I have a less than whisper projector and because we use normal rooms in our homes as media / theater room we select some of the shorter throw projectors that give us the immersion we want for a single row and that places the projector directly overhead and around 3-4 foot above us.

In today’s world the only way to want a projector for me is to have a cinema-like experience in a small room that is treated and pitch black when in use. If I wanted a living room TV-like experience there are now 85-95” flat panels TVs that will give most a nice immersive viewing. So with a dark room for me it is not a beauty contest in terms of the room. I want comfy seating, great sound and a beautiful FP image.

My projector is a tad annoying in the fan department, but I have been putting up with it as my sound system drowns it out in all but the quiet parts. My hope for the last few years has been solid-states LED lower heat and promise of low dB. At first I thought it would be when Viewsonic came out with the X100-4k with a nice big case and very low lumens. It was even a good looking projector with tons of nice features other than the CR sucked. Surely they would fix the CR and I would never have to think about hush-boxes again. They fixed the CR pretty well and went backwards on case design making a screamer again. Other makers did similar. I just don’t get it.

My plan now because I sit right under it and there is no need for lots of extra head room is to build kind of a false ceiling over my seating area. Build it out of solid material and cover the top of it in acoustic foam as well as the real ceiling above the projector. I can make it look good enough and it might even feel cozy with a lower ceiling coming out about 3’ from the back wall.

I’m still hoping for a low heat low noise solid state, but not holding my breath.

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GeoFly

· #13 · 7 d ago (Edited)

@NOAMattD I'm thinking your setup will more difficult to deal with then mine. I posted a photo of my setup. My current projector is 2.6 feet from my head. Seems like it might be possible for me to build a shelve below mine like @SirMaster suggested.

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Sid3Effect

· #14 · 6 d ago

NOAMattD said:
So that's interesting. XPR noise is something I'm worried about looking at the BenQs. Mine has served me well so they have a lot of cred with me right now in terms of durability and reliability. For a ceiling mount you're suggesting some kind of rubber dampening agent, like rubber washers on mounting bolts, or even a rubber sheet contacting the body of the projector housing reduces XPR noise?

Yes I had some improvements using rubber materials. Before the enclosure I was using a rubber backed giant mouse mat material in between the projector and the shelf and it did help with XPR hum. The problem with XPR noise is that at certain frequencies it tends to become very distracting even if it is not necessarily very loud. It's like bass where you feel it in your body and skull and almost makes you feel like your under attack after prolonged periods. I know that is a bit dramatic, but it was stressing me out. I could go upstairs and still hear/feel the XPR hum through the ceiling.

clint357

· #15 · 6 d ago

First, perform a test to see what works. Take anything solid, like a piece of rigid cardboard or a piece of wood and put a couple layers of folded bath towel on top of it. Have one person sit under the PJ and another hold the towel and support piece a few inches under the PJ and see if it helps. We can pontificate on ideas all day, but sometimes you just have to start testing ideas.

Sid3Effect said:
Yes I had some improvements using rubber materials. Before the enclosure I was using a rubber backed giant mouse mat material in between the projector and the shelf and it did help with XPR hum. The problem with XPR noise is that at certain frequencies it tends to become very distracting even if it is not necessarily very loud. It's like bass where you feel it in your body and skull and almost makes you feel like your under attack after prolonged periods. I know that is a bit dramatic, but it was stressing me out. I could go upstairs and still hear/feel the XPR hum through the ceiling.

That may be overly dramatic for the average person, but you are speaking to a self-selecting group of people who are very particular about sound. I had/have a strange high frequency hum from a bad sub amp and I swear that if I work on my theater room and tune into that frequency, it sticks with me for the rest of the day where I think that I hear it everywhere.

Reactions: 2

Daboyle82

· #16 · 6 d ago

NOAMattD said:
Great responses so far.

That's mostly along my lines of thinking. Physical barrier of some sort between ears and source of the noise is the top factor.

Erin, Amir, and anyone else with a Klippel can come to my theater and borrow whatever they want to measure LOL

So that's interesting. XPR noise is something I'm worried about looking at the BenQs. Mine has served me well so they have a lot of cred with me right now in terms of durability and reliability. For a ceiling mount you're suggesting some kind of rubber dampening agent, like rubber washers on mounting bolts, or even a rubber sheet contacting the body of the projector housing reduces XPR noise?

Thinking you forgot a link there bro but if it involves duct tape it must have potential.

haha youre correct, link fixed. if it does work, simply wrap in fabric and mount underneath your projector

PotentialProjectorBuyer

· #17 · 5 d ago

Simply enclosing it seems like not a great solution since the heat still has to go somewhere. The other concern to be aware of is anything near a 200W+ constant heat generator is going to need to be flame resistant. Things like blenders or, well, generators or HVAC equipment that generate heat can have enclosures that are designed to mitigate sound generation but still function. Typically at the cost of more energy being required to still move the heat somewhere, just not as easily as air based heat mitigation.

PotentialProjectorBuyer

· #18 · 5 d ago

I may have heard you wrong. Not an actual quote but the flammable part is at least accurate.

clint357 said:
Take anything flammable, like a piece of rigid cardboard or a piece of wood and put a couple layers of folded bath towel on top of it.

Melamine padding at least is not cheap nor super durable for physical use but is generally good at flame resistance is my understanding. The other issue is the formaldehyde part of it though.

clint357

· #19 · 4 d ago

PotentialProjectorBuyer said:
I may have heard you wrong. Not an actual quote but the flammable part is at least accurate.

Melamine padding at least is not cheap nor super durable for physical use but is generally good at flame resistance is my understanding. The other issue is the formaldehyde part of it though.

I did not say to touch anything to the PJ, but to just hold these items under it to block sound. Also, there are no vents on the bottom so it would not effect the air flow. I don't think that having a towel (just to test) a couple inches under the PJ is going to get hot enough to combust. It is a projector, not an infrared heater.

Sid3Effect

· #20 · 4 d ago

On the x3000i the intake is on the right and the exhaust on the left it doesn't get hot or even warm at the back, top or bottom. This is good because I was able to use right angle cable adapters to allow only a few cm's space at the rear, and this didn't cause any issues. The exhaust air is warm not hot. These things have giant heatsinks inside. Even if the fans failed the heatsink would keep the unit cool enough to allow the unit to throttle brightness or power off long before a fire could start. The fan speed is dynamic in all modes on the x3000i even Eco. It seems that it is a constant speed at first, but I have noticed that if you allow the cabinet to warm up it does actually have an internal temperature sensor that increases the fan speed automatically.

I tested mounting 140mm directly to the right and left sides the idea being that the temperature sensor would then lower the internal fan and make it overall quieter. This didn't really work as I would have liked, but I might try it again soon with just the extra exhaust fan. I have a feeling I was creating more internal heat by having the extra intake.
When using a cabinet it is an advantage to keep the fan speed higher in smart eco or custom as that exhausts more air from the projector which can then be removed from the cabinet easier and more quietly. When the projector is in Eco mode and the fan is slower it builds up heat inside the projector which in turn makes it more difficult to remove from the cabinet quietly.

A material like Alubutyl which I lined my cabinet with is a rubber aluminium sound deadening material that has fire resistance as it's designed for automotive uses. Far more effective and safer than foam or sheets. Also standard rubber would work well. Foam should be avoided. Polyester fibre could work.

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