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Discussion Starter · #1 ·
This weekend I'll be returning to my home town for some weeks during the holidays. This is the time I will build the two beasts I've been dreaming about for 6 months... They are going to be ported designs. The material chosen is 3/4" MDF. Inner measurements are WxHxD 19.68x51.18x15.74. There will be two braces in the box, approx 19.68x15x74 with a 17.3x13.4 rectangle cut out, each brace should displace about 0.96 litres.

The port will be a rectangular one as I don't know where to get 6 or 8 inch ports here, importing is expensive... Inner measurements of the port (millimeters): 400x40x615 (or 15.74x1.57x24.2 inches). I was planning on running the port along the side of the box. I don't think (but I'm not sure) that the air speed will be a problem, at 650 watts input. ca 20m/s @ 12.5Hz and 14m/s @ 21Hz. If I could use Google Sketchup or something I'd given you some nice pictures. :eek:

The internal box volume, including braces, driver and the port lands at 236.3 litres, tuned to 17.77Hz.

It will be a double baffle as well, so the driver is mounted "flush" to the baffle, gives it a cleaner look. What I'll probably do is complete the box, then just glue the outer baffle onto the front of the box.

PDF with graphs, etc: http://www.2shared.com/file/4477811/bceede4/Tempest-X-vented-box.html

T/S parameters of the Tempest-X: http://www.subwoofer-builder.com/driver-exodus-tempest-x.htm

Bassbox Pro design file: http://www.2shared.com/file/4477913/e402e6ff/Tempest-X_240L_slotport_F3_195Hz.html

So I guess my question is, do you see any showstoppers? Or should I just get to it?

Regards,

Mathias
 

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Using WinISD, port air speed with 600 watts input would be 21 m/s at 20 hz, 29 m/s at 15 hz and peaks at 33 m/s at 11 hz. The port dimensions are wide and narrow, not the best for air flow. Changing the dimensions to 3" by 9" by 27" long would be a better choice. It will help with air flow and has a slightly larger surface area to reduce air speed.
 

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Discussion Starter · #3 ·
Using WinISD, port air speed with 600 watts input would be 21 m/s at 20 hz, 29 m/s at 15 hz and peaks at 33 m/s at 11 hz. The port dimensions are wide and narrow, not the best for air flow. Changing the dimensions to 3" by 9" by 27" long would be a better choice. It will help with air flow and has a slightly larger surface area to reduce air speed.
Yeah I kinda had an itch saying that the port would be a problem in this respect. However, inputting your parameters into bassbox shows only 1m/s difference on most frequency, strange. I thought I'd do the port as wide as the depth of the box for simplicity. :)

Well, it just means a bit more cutting and planning. Thanks for the input!
 
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