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Old 17th March 2013, 06:47 PM   #11
AndrewT is offline AndrewT  Scotland
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Have you read about Linkwitz transform?
That will tell you a lot about getting back some bass from a sealed box speaker.
But it comes at a price: Very high power at the bass frequencies. So much so, that maximum SPL is severely compromised if you ask the transform for too much downwards extension of the bass.
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Old 17th March 2013, 07:08 PM   #12
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Location: Mar del Plata, a BIG seasonal getaway city, can see the Ocean from our residence.
MDF by all accounts seems to be the default material to use for enclosures, Plywood is a different animal...One must choose a "void free" type of plywood...which is an 'un-common type....and consistency seems to be highly variable. Internal bracing can be a multitude of types....the idea of build it stronger than you think it needs, seems to be in order here. Stuffing the inside has two benefits....Reducing the size of the sealed enclosure appx 15% via Isothermal Process.....Damping of internal reflections...so that waves inside the enclosure do not rebound off the walls to "re-energize" the cone.
Myself, I use MDF for its' workability....& I won't use anything less than one inch thickness, no matter the size. This makes for a very stout structure...albeit very heavy inert structure...but I will "suffer" that choice. I use two inch screws(For 1" thickness), pilot hole, spaced every five inches, simple butt corners(One inch is great for simple butt) appropriate wood glue & screw it all down...very stout!!

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Last edited by Richard Ellis; 17th March 2013 at 07:17 PM.
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Old 17th March 2013, 07:18 PM   #13
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Quote:
Originally Posted by Kingnoob View Post
Stereo Integrity site suggests a 3 cubic foot sealed box
Any Tips on bracing? or building box.
I take it Dampening material inside makes the box sound louder?

If MDF better than plywood for sealed box?
Braces can be made of the same material the rest of the cabinet is made from, around 3" strips connecting opposing sides stiffen walls.
Dampening material can make a sealed box acoustically appear larger.
In a ported box dampening can reduce resonances, but will also reduce output level.

MDF is not as rigid as good plywood, and does not hold screws as well, and absorbs moisture more readily.
It is easier to get a nice looking finish than plywood, but does not hold up well on the road.
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Old 17th March 2013, 09:10 PM   #14
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3/4" plywood is rather durable right?
Void free is the best correct
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Old 17th March 2013, 10:30 PM   #15
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Plywood, void free/high quality is the best inside/outside where there's humidity.
Another thread on the same driver by OP here,
SI sub?? help
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Old 17th March 2013, 10:48 PM   #16
tinitus is offline tinitus  Europe
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closed apperiodic design
especially leightweight, and portable
though light, still very stiff and 'dead', due to bracing
and stuffed, the bracing also works as acoustic valve, for the apperiodic system
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Old 21st March 2013, 07:28 AM   #17
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DO I need to use a box building program??to create a blue print or what

I'm not sure how to cut speaker holes... but Is it hard?

Last edited by Kingnoob; 21st March 2013 at 07:37 AM.
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Old 21st March 2013, 10:51 AM   #18
Jay is offline Jay  Indonesia
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Quote:
Originally Posted by Kingnoob View Post
DO I need to use a box building program??to create a blue print or what
Of course. You need to use a program to calculate box volume, driver location on baffle, port diameter and length, and in some cases throat cross section, mouth cross section, length of pipe, etc.

Quote:
Originally Posted by Kingnoob View Post
I'm not sure how to cut speaker holes... but Is it hard?
If you don't know, it means you don't have the tools, it means difficult (I prefer to pay third party to build mine)
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Old 21st March 2013, 02:52 PM   #19
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Kingnoob,
You seem really interested. As Jay said you can use the services of a professional carpenter. People that do it themselves use a jigsaw, a router or a CNC but you don't have to learn if don't feel to.
By the way what is your flag/country. Do you use metric or imperial units where you live.
CNC Routing
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Old 30th March 2013, 04:28 AM   #20
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Quote:
Originally Posted by Inductor View Post
Kingnoob,
You seem really interested. As Jay said you can use the services of a professional carpenter. People that do it themselves use a jigsaw, a router or a CNC but you don't have to learn if don't feel to.
By the way what is your flag/country. Do you use metric or imperial units where you live.
CNC Routing
me & a freind built box but I have to seal up up with extra wood bracing , plus it needs more bracing so back of box doesn't flex.
I went sealed but box is large enough to make it ported if I disliked sealed.
approx 4.5-4.8 cu footer

Awaiting box'es need for extra bracing it is ported because back is open down-facing, sitting on the Styrofoam that came with the sub when shipping...Port doubles output almost.. but It seems like bass is not very controllable
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Last edited by Kingnoob; 30th March 2013 at 04:32 AM.
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