Sandbox OB H Frame Build Completed

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AlexH

Sandbox OB H Frame Build Completed
« on: 5 Jun 2020, 10:08 pm »
So I have decided to try and build a sandbox version of the H frame OB sub. Is the effort worth it?  I have no idea. I was originally going to build two sandbox sealed subs and upgrade my X-Statiks because it fit into this year’s audio budget. But after reading everyones comments on how good OB base sounded, I decided to build one OB this year and a second one next winter. I will be building both H frames now though because if you are going to build one you might as well build two at the same time.  After talking to Danny briefly when ordering supplies he said ¼” or 3/8” of sand was good enough. Since I was not going to use no-rez I thought I would go with ½” of sand because bigger is always better.  :roll:

My Plans:

 All four sides will have 3/4” mdf  / 1/2” sand/ 3/4” mdf. The exterior will be veneered with fiddleback Makore framed by curly Maple on the front side and domestic cherry on the backside. I my case both front and back will be visible.  I am trying to match my X-Statiks as much as possible which are done in pommele Makore with curly maple. I could not find pommele Makore at a reasonable price but did find a good price on some fiddleback Makore. And since I am not going to use no-rez I thought I would veneer the inside with domestic cherry veneer so it would looked good when I showed my friends, which most of whom couldn’t care less. :lol:

I see three possible outcomes from this build:

1)   At the end of this thread you will see what I consider a nice piece of kit. :thumb:

2)   At the end of this thread you will see a failed project sitting on the burn pile outside of my shop. :cry:

3)   At this end of this thread you will see a couple of OB subs sitting in my shop because they are too damn heavy to move and transport home. :o

Stay tuned.
« Last Edit: 4 Jul 2020, 06:37 pm by AlexH »

AlexH

Re: Sandbox OB H Frame
« Reply #1 on: 5 Jun 2020, 10:15 pm »
Here are my first pics:



Because every good build starts with a pic of a 4 x 8 sheet of MDF  :lol:




And then a pic of a 4x8 sheet of MDF cut into little pieces





AlexH

Re: Sandbox OB H Frame
« Reply #2 on: 5 Jun 2020, 10:22 pm »
I decided to build the top and bottom panels first.  Fill them with sand before assembly. I had a sheet of 1/2" mahogany mdf core plywood in my shop for 15 years and I finally found a use for it. I made the 1" baffle and  the 1/2" spacers you see out of it.







Tyson

Re: Sandbox OB H Frame
« Reply #3 on: 5 Jun 2020, 10:23 pm »
Dude, that's gonna be so ridiculously over the top.  Love it!

AlexH

Re: Sandbox OB H Frame
« Reply #4 on: 5 Jun 2020, 10:29 pm »
OK first mistake. After building the top and bottom panels I could here the sand moving if I shook the panel.  So I drilled a 3/8" hole in the end, used a funnel and a 1/4" dowel to pack the sand into the panel.

Note to self: You should have just filled the panel through the hole in the first place. :duh:







AlexH

Re: Sandbox OB H Frame
« Reply #5 on: 5 Jun 2020, 10:32 pm »
Building of side  panels.












« Last Edit: 6 Jun 2020, 09:40 pm by AlexH »

AlexH

Re: Sandbox OB H Frame
« Reply #6 on: 5 Jun 2020, 10:39 pm »
And a brief mock up.


« Last Edit: 6 Jun 2020, 11:43 am by AlexH »

AlexH

Re: Sandbox OB H Frame
« Reply #7 on: 5 Jun 2020, 10:42 pm »

Here are the baffles veneered with the cherry.







« Last Edit: 6 Jun 2020, 11:45 am by AlexH »

Hobbsmeerkat

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Re: Sandbox OB H Frame
« Reply #8 on: 6 Jun 2020, 01:09 am »
That's pretty rad! Whenever I decide to build a pair I'll probably do something like this or some form of constrained layer damping and norez.
I'm curious how much of a difference sand makes in an OB setting, esp since they don't have to deal with internal pressures of sealed subs.

Captainhemo

Re: Sandbox OB H Frame
« Reply #9 on: 6 Jun 2020, 06:39 pm »
They're gonna be cool Alex  :thumb:

Anxious to see what they come in weight wise... I know one of our  dual kits made from   solid 1.5" MDF  and  1" Medex (baflle/braces) is around  75 lbs.....   some quick math  and I figure  you'll get  maybe .3 cu ft of sand  in  the cabinets so roughly   an additional 30 lbs....   might not be too brutal  .... 

jay

rollo

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Re: Sandbox OB H Frame Build
« Reply #10 on: 6 Jun 2020, 08:41 pm »
  Does the thicker cab or sand actually do something measurement wise. Is it overkill ? Not against it need to know question thanks.

charles

AlexH

Re: Sandbox OB H Frame Build
« Reply #11 on: 6 Jun 2020, 09:38 pm »
To be honest I really don't know. I had posed that same question earlier.  My thought is that it will deaden the panel rez. When I told Danny what I was going to do he didn't say not to.  :D










MHL

Re: Sandbox OB H Frame Build
« Reply #12 on: 6 Jun 2020, 11:14 pm »
A little history on sand filled speakers pioneered by Gilbert Briggs of Wharfedale starting back in the 1930's.

https://www.inner-magazines.com/audiophilia/wharfedale-sfb3/

rollo

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Re: Sandbox OB H Frame Build
« Reply #13 on: 6 Jun 2020, 11:24 pm »
To be honest I really don't know. I had posed that same question earlier.  My thought is that it will deaden the panel rez. When I told Danny what I was going to do he didn't say not to.  :D

   Alex my thought would be exactly the same. Deaden that sucker. If Danny did not reject thought done.  MHL thanks for the read. I actually use sand filled plywood boxes with a wood plinth for my TT's Mono and stereo. The most affective support we ever used.


charles

AlexH

Re: Sandbox OB H Frame Build
« Reply #14 on: 7 Jun 2020, 07:17 pm »
Was able to get a little more work done today. Got the dado's cut, and some more veneer done to the interior
















Hobbsmeerkat

  • Jr. Member
  • Posts: 258
Re: Sandbox OB H Frame Build
« Reply #15 on: 7 Jun 2020, 08:05 pm »
Those are coming along great!

AlexH

Re: Sandbox OB H Frame Build
« Reply #16 on: 8 Jun 2020, 08:30 pm »
Pic of the fiddleback Makore veneer. Absolutely beautiful stuff.




rollo

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Re: Sandbox OB H Frame Build
« Reply #17 on: 8 Jun 2020, 08:47 pm »
  What a talent you have. Looking great.


charles

AlexH

Re: Sandbox OB H Frame Build
« Reply #18 on: 9 Jun 2020, 11:08 am »
Thank you for the complement.

AlexH

Re: Sandbox OB H Frame Build
« Reply #19 on: 14 Jun 2020, 06:35 pm »
Was able to get some done on these. It seems Pickleball and bike riding keeps getting in the way.