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4 Pi Home Theater Build [message #67585]

Thu, 12 May 2011 13:31

NWCgrad
Messages: 143
Registered: March 2010
Location: Frederick, United States ...

Master

After a couple of years of going back and forth between the 4 Pi and the Deluxe Econowave, I have committed to building three 4 Pi's. Of which, two will be vented with the center being sealed (per suggestion from Wayne Parham). I will be going fully uprgaded (JBL 2226H and B&C DE250 + upgraded crossover componets).

Unfortunately I can only complete two of the speakers now - but I am building the third cabinet so it will be ready!

I am adding extra reinforcement to the MDF cabinets because the speakers will need to survive at least two - possibly three - military moves. I am moving this summer for 2 years in Cambodia, so I need to ruggedize as best I can (was going with birch plywood but had issues beyond my control so ended up with MDF). To accomodate, the speaker depth has been increased from 14.25" to 15.75" - internal volume will be as close to Wayne's spec as I can get (+0.1 Ft^3) so not to screw up tuning or induce standing wave issues. Both the front and rear baffle will be 1.5" thick (however, the back baffle has cutouts to bring the volume down from .75" to .5" - the cutouts shown in the second attachment will not be used as a window brace but rather will be glued and screwed to the back panel).

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Attachment: window brace.jpg
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VIRIBUS MARI VICTORIA

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Re: 4 Pi Home Theater Build [message #67586 is a reply to message #67585]

Thu, 12 May 2011 13:42

NWCgrad
Messages: 143
Registered: March 2010
Location: Frederick, United States ...

Master

Here is the cut MDF for the project:

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VIRIBUS MARI VICTORIA

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Re: 4 Pi Home Theater Build [message #67587 is a reply to message #67586]

Thu, 12 May 2011 13:59

NWCgrad
Messages: 143
Registered: March 2010
Location: Frederick, United States ...

Master

Some of the smaller pieces were damaged, so I glued them using Titebond II.
index.php?t=getfile&id=394&private=0

Gluing the ports:
index.php?t=getfile&id=395&private=0

Attachment: 4 Pi Build 003.jpg
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Attachment: 4 Pi Build 001 - reduced.jpg
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VIRIBUS MARI VICTORIA

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Re: 4 Pi Home Theater Build [message #67588 is a reply to message #67587]

Thu, 12 May 2011 14:08

NWCgrad
Messages: 143
Registered: March 2010
Location: Frederick, United States ...

Master

Final pictures...for now.

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VIRIBUS MARI VICTORIA

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Re: 4 Pi Home Theater Build [message #67591 is a reply to message #67585]

Thu, 12 May 2011 19:04

Dave_S
Messages: 28
Registered: April 2011

Chancellor

It looks like you are making good progress.

My 4Pi speaker kits arrived Monday. I chose the same upgrades as you, but I took a step down in the capacitors.

I am tweaking the design and will probably begin the build this weekend. My original plan was to use plywood sides and a solid wood front. Then, I started worrying that the plywood is dimensionally stable and the wood would want to expand and contract. People online have reported the solid wood cracking with that type of design. I decided to go with mostly plywood. Then, I read Wayne's comments about the possiblity of crud rattling in the voids of some types of plywood, so I decided to use baltic birch. I still may do a veneer over the top since I would prefer cherry. MDF with a cherry veneer probably would work for my purpose, but I am more comfortable with working with plywood.

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Re: 4 Pi Home Theater Build [message #67594 is a reply to message #67591]

Thu, 12 May 2011 21:16

NWCgrad
Messages: 143
Registered: March 2010
Location: Frederick, United States ...

Master

Progress seems to be going well, at least the enclosures are square! This is my first build with MDF, and I avoided the cutting by having them CNC'd.

The final boxes will be covered with either oak or cherry veneer, with the front and rear baffles painted flat black (will use a foam roller to apply Duratex the same as BigmouthinDC).

I am not sure if either veneer is better than the other - does anyone have info? Seems like cherry is less porous than oak, this may be important during overseas transport.

Good luck on your build.

VIRIBUS MARI VICTORIA

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Re: 4 Pi Home Theater Build [message #67598 is a reply to message #67594]

Thu, 12 May 2011 21:35

Wayne Parham
Messages: 18787
Registered: January 2001

Illuminati (33rd Degree)

That's excellent! Thanks for taking the time to write-up the build process and include pics. I love it when you guys do that!

On the veneers - wait a day and see if Epstein sees this thread and gives his 2¢. He is really a master woodworker, and will probably have some helpful advice. If he doesn't see it in a day or so, post your question on the Craftsmen forum.

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Re: 4 Pi Home Theater Build [message #67601 is a reply to message #67594]

Thu, 12 May 2011 23:31

Dave_S
Messages: 28
Registered: April 2011

Chancellor

If you are looking for durability for moving, I would say use oak over cherry.

I just made a couple of TV stands as gifts over the winter out of cherry plywood and solid cherry. Cherry is a much softer wood and reminded my more of working with a soft wood like pine. It was almost fun because of how easily it sanded. However, it probably dent's much easier than oak.

Oak is more porous, but finish would seal the pores.

There is a link on veneering a few posts down. The recomendation to use only the stuff that warns about being toxic or explosions is pretty valid. I had good luck with veneering until I selected a latex? based contact cement due to the smelly stuff being out of stock. The finish soaked through the veneer and disolved the contact cement. I haven't done any veneering for 20 years though.

For shipping, you will want to wrap the speakers with plastic and possibly throw some desicant in with the speakers. I was just in Singapore cleaning up after an inadequately prepared shipment.

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Re: 4 Pi Home Theater Build [message #67602 is a reply to message #67591]

Fri, 13 May 2011 06:16

Bill Epstein
Messages: 1088
Registered: May 2009
Location: Smoky Mts. USA

Illuminati (2nd Degree)

Dave_S wrote on Thu, 12 May 2011 20:04

My original plan was to use plywood sides and a solid wood front. Then, I started worrying that the plywood is dimensionally stable and the wood would want to expand and contract. People online have reported the solid wood cracking with that type of design.

It's amazing to me that thousands of years after the Egyptians invented frame and panel doors, people are still unaware of the seasonal movement of wood. They think cabinet doors are made of 5 pieces solely for aesthetics?

Wayne exaggerates; do I have to trot out the pic of the Bat Speakers again?

Table of wood densities/hardness http://www.engineeringtoolbox.com/wood-density-d_40.html

NWC, you're going to finish with polyurethane? Ordinarily, I'm against it, but just as contact cement veneering will protect the MDF from moisture, so too will goopethane protect the veneer. At least better than the alternatives. You can make it less shiny-plasticky-looking by rubbing out with 0000 steel wool and paste wax.

Ask at your local Lowes/Depot in receiving (just walk back there) for them to save you the large-bubble bubble wrap that some refrigerators come packed in. Pack your speakers in that and forget about which veneer is harder.

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Re: 4 Pi Home Theater Build [message #67610 is a reply to message #67602]

Fri, 13 May 2011 20:01

NWCgrad
Messages: 143
Registered: March 2010
Location: Frederick, United States ...

Master

Bill Epstein wrote on Fri, 13 May 2011 06:16

NWC, you're going to finish with polyurethane? Ordinarily, I'm against it, but just as contact cement veneering will protect the MDF from moisture, so too will goopethane protect the veneer. At least better than the alternatives. You can make it less shiny-plasticky-looking by rubbing out with 0000 steel wool and paste wax.

Ask at your local Lowes/Depot in receiving (just walk back there) for them to save you the large-bubble bubble wrap that some refrigerators come packed in. Pack your speakers in that and forget about which veneer is harder.

If polyurethane will provide the best protection then yes. Is there any particular brand I should avoid? I plan on buying the finishing materials from a local wood retailer (http://hardwoodsincorporated.com/tools_accessories.aspx) instead of the big box stores.

Is polyurethane compatible with HeatLock veneer glue? I cannot put a bumpersticker on my car without bubbles, I am afraid that contact cement is a disaster waiting to happen.

Thanks for the tip about the large bubble wrap, I will pursue that option.

VIRIBUS MARI VICTORIA

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