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post #1 of 14 Old 10-05-2013, 07:42 PM - Thread Starter
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The Plasmad Pocket Sub




41x48x15" roughly 12-13cuft after bracing
single sheet baffles front and back but the bracing should take care of that.
2" port about 37" long
SI18
Bash 500w


Since there are more than a couple of people out there that have flat pannels in the corner I figured I would design a sub that would benefit us. Since its not that wide and the driver is back in the corner you won't run the risk of it hitting an entertainment center. The other part is that I needed something with a bit more extension than my tapped horn with an 8" drive . This thing could do about 110db at 35hz but dropped like a rock after 28hz.



After doing some digging and waiting around I jumped on the stereo integrity deal last year. Instead of going crazy multiple sub and watt builds, as I didn't have the room or acceptance from the wife to do it I decided to stay within some limits and build a fairly large box that would work with a 500watt bash amp. Sims plotted out 110 at 20hz and about 107 at 12hz. The driver will run out of gas at 9hz but its beyond tunning. It won't do reference at 120db but I'm wasn't looking for that. You may be able to turn the box into a dual sealed design and hit it with a ep2500 but I had no desire to do that as it would add more and more dollars to it. The design of this sub for what I wanted was a single driver and plate amp. No muss no fuss, just plug in and go.




Having never build a ported sub before and just building, ported speakers, sealed subs, FLH, and tapped horn subs this one was new. I put it all together with two sheets of 3/4 arruco and used the left over section to brace the heck out of the interior. In the above image I showed a middle set of crossbraces and that was wrong. There is just braces on both baffles and then and interior rib running around the each interior width wall(top, bottom, front and back).



Its pretty massive but the TV hides it well. Still haven't had time to measure it but the bass is incredibly smooth and uniform out of it.


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post #2 of 14 Old 10-05-2013, 07:51 PM
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did you modify the resistors in the plate amp?

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post #3 of 14 Old 10-05-2013, 08:03 PM
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with the stock values that come in the amp, the high pass filter will be around 30hz, q=1.3, which gives this:

red = raw response. green = built in filter.



http://www.parts-express.com/pdf/300-752.pdf

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post #4 of 14 Old 10-05-2013, 08:59 PM - Thread Starter
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scratch that,

its an oaudio sub with a 12hz hpf and a bit of a boost but they went out of business so i keep calling them Bash.
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post #5 of 14 Old 10-06-2013, 09:12 AM
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Very nice ! What is your center channel ?
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post #6 of 14 Old 10-06-2013, 09:52 AM
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"scratch that"

yeah...my bad, you put a picture of the amp right there! not sure how I didn't make the connection...anyway, I've been thinking that his kind of form factor or something quite similar could be used for multiple purposes and am glad that you decided to make it happen. it is a good solution for minimizing "into to the room" footprint, while still allowing for a big sub and some interesting placement options.

props.

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post #7 of 14 Old 10-08-2013, 08:12 PM - Thread Starter
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yeah its a great sub and can be put together for about 500-550.


seems like everyone just goes over kill with these SI drivers in the multiple sealed configuration though.
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post #8 of 14 Old 01-08-2014, 12:43 PM
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bump...just because I linked to it again. :-)

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post #9 of 14 Old 01-15-2014, 07:13 PM
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Neat build. When the levels get up, does it move around at all?
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post #10 of 14 Old 03-20-2014, 08:15 AM - Thread Starter
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Not that I know of.

One of the panels sits on it and it hasn't fallen off the wall. I was going to readjust the panel but never got around to it.


I should see if I can find some cut sheets for it. I used some spare wood to brace it.
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post #11 of 14 Old 04-26-2014, 08:44 AM
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bump...just because I linked to it one more time! :-)

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post #12 of 14 Old 04-26-2014, 09:49 PM
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Quote:
Originally Posted by stgdz View Post

Not that I know of.

One of the panels sits on it and it hasn't fallen off the wall. I was going to readjust the panel but never got around to it.
Thanks for the reply but I didn't see it until LTD bumped it this morning.

I wondered because I have 2 FTW21 and two more due to arrive shortly. I wish to place them in an an area behind the screen in 2 tallish thin cabinet similar to yours but a little L shaped in cross section with this volume extending out 20-30cm from the main vertical box at the bottom and would be the height of the drivers, about 60cm. With 2 drivers on the bottom of each vertical face, looking directly towards the MLP, I'm wondering if they'll move at level, or if I should make each box dual opposed with a driver in each pointing toward the L/R walls and the inner pair facing each other. The first is aesthetically what I'd prefer.

Sorry for rambling, just thinking out loud. Might just do it the way I want, and if they move, screw some wood into the front panel behind the screen and then to the brick walls beside. They'll be 18mm Arauco ply with a modified matrix style bracing so the should be heavy.
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post #13 of 14 Old 04-26-2014, 10:07 PM
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Though this is a great solution, and one that would also work well behind a screen in the front wall, a triangular CSA version would also work and potentially look great, even if the port might be more difficult. Still TOL.
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post #14 of 14 Old 06-01-2014, 11:22 AM - Thread Starter
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Not much time these days

off of soho's measurement dvd

10hz 84db
15hz 85db
20hz 95db
30hz 95db
45hz 97db
55hz 101db
65hz 94db
80hz 90db

I'm pretty certain those sub 20hz numbers are accurate with my ratshack meter rolleyes.gif
I have double pane glass windows with internal decrocrative window braces. It was flexing them pretty good at 10hz and thats about as good enough for me when it comes to measuring these things.
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