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Discussion Starter · #1 ·
Hi everyone.


Please note that my intention in posting this thread is not to solicit sales or market an item, but to see what you guys think of an idea to potentially offer a unique hushbox for the LT150.


The technical details of specifying the components for a high-quality hushbox have been fairly well discussed on this forum, so I won’t bother you with the details at this time (glass, fans, etc.).


I envision a compact enclosure made of exotic hardwoods with a furniture grade finish. An enclosure that you could bring home to your wife and tell her you will be hanging it from the ceiling or setting it on the coffee table. Based on a cursory survey, it appears that the only hushboxes that are available are somewhat bulky and unorthodox. I propose a very compact, sleek design that would blend nicely with furniture, yet be beautiful enough to “stand outâ€.


I am a civil engineer by day, but also an accomplished woodworker, having built furniture, cabinets, and a few beautiful electric bass guitars of exotic hardwoods.


Obviously, such an enclosure would appeal to only a small group of people (LT150 owners with a good sense for design and aesthetics), but perhaps the concept could be carried over to the next “hot†projector.


I am confident that I can build an enclosure that will perform the necessary noise-reduction and be beautiful as well. I just don’t know if a market exists. Of course, if I decide that such a market exists, I would follow the appropriate procedures with the AVS Forum to assure compliance with the rules, before marketing anything here.


What do you guys think? Is there a significant potential niche market? Do you think that people would appreciate an aesthetically pleasing hushbox, or do people just want something inexpensive (home-built)?


Jeff Streitz

Iowa City, IA

 

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Discussion Starter · #3 ·
Lawdawg-


The goal would be to bring it to market near the price point of the hushbox that is currently available, offering a different aesthetic with similar performance and cost.


Jeff
 

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Jeff,


I considered hardwood before choosing 3/4" MDF for my VT540 dustbox/hushbox. The extreme temperature cycling does not bode well for any solid wood product (I'm an EE and also a woodworker). I also considered applying veneer over MDF but ended up with one coat of primer and two coats of flat black - that's what made the box the least noticeable in my particular location.


I used fairly conventional cabinet construction and cabinet hardware (rabbeted and screwed glue joints and European-style concealed hinges). I segregated the projector air intakes (of which there were two) and the single exhaust port with an internal hushbox partition, effectively creating seperate cold and warm air chambers, which actually reduced exhaust temperature a couple of degrees as it avoided recycling exhaust air to the intakes. Then I added a HEPA filter and two quiet muffin fans with battery backups (then we never had the rolling California blackouts I was anticipating). The exhaust temps declined further with the fans, and further still when I used closed cell foam as gasketing between the projector and partition.


The worst case temperature rise is following a power failure when the projector doesn't get a cooldown cycle for the bulb, hence the fans and the cold air/warm air plenums - when you pull the plug on my box, the battery-powered fans continue to push air through the projector to cool down the optical assembly. (My NEC manual warns that the projector can be damaged internally by the lack of cooldown.)


The projector hangs from a conventional Chief ceiling mount bolted to the inside top of the box, and can be aimed in all three axis and removed through the hinged front door, which also has an inset plexiglas disc that the lens shines through.


Generally I'm pleased. The VT540 is bigger than an LT150 but I wanted the box as small as possible. That and the other required features prolonged the design and construction for the better part of a week.


For your LT150 hushbox, do not underestimate the design effort. That projector lacks UL approval for inverted operation, thus you cannot buy a ready-made ceiling mount such as I used, so plan on adjustable aiming hardware. It also is noisier and hotter than my VT540 and it may prove harder to segregate the intake and exhaust air.


I'm not saying it's impossible, just that the effort will probably be greater than you anticipate and the market fairly small. Not to mention that I've been hanging around the AVS Forums for over two years and find most members to be - ahem - somewhat demanding as customers. I hope you have lots of tolerance for such behavior.


I'd be interested in pictures of your prototype.


Gary McCoy

San Jose, California

 

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Discussion Starter · #5 ·
Thank you for the well-written response Gary! You raise many important points. I have been giving this project some more thought, but seeing how this thread dropped quickly with few responses, it is apparent that the interest level in such a product might not be sufficient.


Jeff Streitz

Iowa City, IA




[This message has been edited by Jeffrey (edited 09-12-2001).]
 

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i used cherry plywood with some cherry trim and some cherry edge tape. no issue with heat and looks great.


greg


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If anyone is interested in a somewhat semi-hush box, I built one simply using a pine intable. It is a simple intable (for use next to beds) with a drawer. I used pegboard for the bottom for better ventilation - when you pull the drawer out, there may not be a bottom. I bought mine at a nude furniture store and stained it - that way I could find something that was right for my setup.


Just alternative way to reduce some noise and still look good. I love it b/c people never know I have a projector until I show them.




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Gary M,


I'm impressed with your comments, and (in words alone) it's hard to understand your design. Would you please include (or e-mail me) a diagram (scanned, drawn) showing the divided areas, fan location, temp sensors, etc.


I have a NEC G-15 and am designing mine - and it will be in the garage (warm summers, cool damp fall/winters, and dusty); I was going to use a bathroom fan to exhaust air, with a HEPA intake; but maybe you've got a better mousetrap.



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The search for excellence is unending . . .
 

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Jeff,


I would have been interested in purchasing a hushbox made out of wood for my D-ILA, but I'm now awaiting delivery of a whisperflow hushbox from Dave in New York. I asked him if he could build one out of wood that I could cover with sheetrock and make it look built in complete with crown molding to match the rest of the room, and he said it would not be dense enough to mask the sound. I still may try to cover his plexiglass box with sheetrock or wood and try to add crown molding. I just don't like the idea of a big ugly plastic box hanging from the ceiling in a room that otherwise has wonderful wood cabinets and molding. No offense meant to the builder of the whisperflow hushbox. I don't have the woodshop expertise to build it myself or I would have to take a year and learn a new hobby (woodworking). I still might be interested if the whisperflow hushbox doesn't work out.

Larry
 

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Yes - how about a hushbox with Brazillian rosewood

back and sides, an Englemann Spruce top, some

Abalone inlays...


Whoa - I'm getting confused with ordering custom

acoustic guitars - which is my other "money-sink" hobby.


Greg
 

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Discussion Starter · #11 ·
It doesn't look like I will be putting the time into the design/construction/marketing of these hushboxes. I'm so busy taking care of my 4-month old twins and 4-yr-old daughter that I don't even have time to watch movies.


I think the way to do it would be MDF and veneer. There are some great looking veneers available.


Morbius- I have built a few custom electric bass guitars. The beauty of the woods is what drove me to ask the questions in the title of the thread. BTW, how about a nice box of curly-figured Koa?


Jeff
 

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Jeffrey,


Curly-figured Koa? We can call it the

"Hawaiian Hushbox"!


I wonder if we can get James Goodall interested in that?


Greg

 

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Discussion Starter · #13 ·
Yes Greg, The Kona Quieter, The Maui Muffler, The Molokai Mute, The Hana Husher... You get the idea http://www.avsforum.com/ubb/biggrin.gif


Jeff




[This message has been edited by Jeffrey (edited 10-03-2001).]
 

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Curly-figured Koa? Isn't she the shapely lass in the grass skirt that greets you at the airport in costume and lei's you?


Stew M, as I've said before I've been unsuccessfull at taking pictures of my hushbox, as it's been painted flat black inside and out, and I've only got a web cam. Nor did I retain the few pencil sketches I made (which did not exactly represent what I built anyway). I have, however made several descriptions in several messages. I would suggest you proceed as follows:


1) Study the projector carefully and note what areas are cold air intakes and what are warm air exhausts. These will be seperated from one another via the partition inside the box, which effectively divides the box interior into a cold air chamber and a warm air chamber.


2) To cool my 160w projector I only needed two small muffin fans, which suck air through the HEPA filter on the side of the box, and one blows the cool air directly onto the side air intake, and the other blows against an air deflector which directs this air stream against the second, front-located projector air intake.


3) My projector exhaust is above the lens of the inverted projector, which mandated that I hollow out the front door of the box to avoid obstructing the exhaust flow. The actual box exhaust is two round holes on top, so any sound is directed at the room ceiling (a 16ft cathedral ceiling, so I don't hear the fans).


4) Consider projector cabling and access - my cables enter via a notch in one rear corner, foam gasketed to avoid air leaks, and the rear panel is screwed but not glued on, and is removed to pass cable connectors inside, then replaced.


5) As I stated in one prior message, I monitor air temps with a simple probe thermometer - the overtemperature cutoff is built into the projector itself, all I did was confirm it had this feature.


6) Preventive maintenance on my projector includes air filter cleaning every 100 hours - so the front of the box has spring-loaded European cabinet hinges and I can reach the cable connectors just behind the door, then the whole pj comes out the open front after I loosen the thumbscrews on the Chief mount.


It seems to me your application is somewhat different, being in an adjacent room - and your projector is much hotter than mine. However, you also do not need a tiny box which was a design objective that caused me a lot of grief, but was needed for spousal approval of the plan. I would suggest you go with the high capacity exhaust fan, and locate the air intakes on the box as near the projector air intakes as is practical, so that as you exhaust the warm air, cool filtered air flows directly onto the pj intakes.


If you want the emergency cooldown feature I implemented, you could mount some DC fans in series with the exhaust blower, and arrange to have them come ON when power goes away, by use of a "double throw" relay which has an AC coil and switches the DC battery voltage via the contacts. The relay contacts will be marked "NC" and "NO" which stand for normally closed, normally open.


Alternatively, use an UPS with enough capacity to run the projector, the blower, and the remote control repeater through the pj cooldown period, and shut off the pj manually as soon as power failure occurs, and allow it to do it's own cooldown while powered by the UPS.


Think through all the design features you need, make drawings, and begin construction. Nothing obscure or difficult about it IMHO (sorry but it's difficult to be objective when you've been a practicing EE for 25 years).


Gary

 

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Gary, do you have any more details on the fans that you used?? Where you bought them, make, model, price, part number? I would like to start putting mine together and if the fans you chose are working fine, I would like to use the same ones. Same for the HEPA filters. Thanks for the help.
 

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OK, I checked at home. The fans I'm now using are Enermax model UC-8FAB. These are double ball bearing, variable speed, 12v DC fans in the popular 80mm size (as used in PC power supplies). These are much quieter than the original brand "X" fans I got at Fry's, even though I have them adjusted to maximum 3000 rpm - they have an adjustment to go as far down as 1000 rpm if needed. I needed to replace my Antec HTPC power supply fan and discovered these - ended up using two in the hushbox as well. They are a strange purple color with clear blades and gold-plated wire guards.


I bought them at $10.99 apiece at Central Computer Systems at 3777 Stevens Creek Bl, Santa Clara, CA 95051. They also have stores in San Francisco and Newark. The Central part number on the barcode sticker is MISCCF8C3P3S. They also have a web site (I can't tell where your location is from the Forum profile):

http://www.centralcomputer.com/PriceList/PriceList.htm


These come with both standard motherboard fan plugs (three pin for speed monitoring) and 2-pin inline adapters for standard disc drive power harness - the harness is about a foot long, and the speed adjustment is another 2-wire harness with a little tweeker pot at the end, also about a foot long. Highly reccomended, 3000 rpm is whisper quiet, and 1000 rpm is totally silent.


The HEPA filters are Eureka part number 60140 for a package of two for about $16 at a Sears store (vacuum cleaner accessories rack), but you can probably get them elsewhere. They are pleated paper, rated for 0.3 micron filtration, and are about 4X4.5X5/8th's inches including some rubber and foam gasketing glued to them. I have vacuumed the exterior of the HEPA filter when I cleaned the projector filters every 100 hours, so far after 440 hours of projector use, I'm still on the first HEPA filter.

Gary
 
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