Hello everyone, to make a long story short, I had someone design me a ported enclosure for the Alpine SWS-10D4 subwoofer which will be used for home theater duty.
Being that I had certain size constraints, the external dimensions of the enclosure with 0.75" MDF would be 12"W x 12"L x 28"H with a slot ported tune of 25hz. (Downfiring driver)
Using the internal dimensions of 10.5 x 10.5 x 26.5 yields a volume of 1.69 ft3, inputting the internal volume and port dimensions of 1.25"H x 10.5"W, WinISD recommends a port length of 30.36 inches but after reviewing the cut list for the enclosure designed for me, the slot port definitely seemed MUCH longer.
I confirmed that by modeling the enclosure in Sketchup and found out that the port length using the center was 48.76 inches (attached a screen shot)
I'm not really well versed in the art of creating ported Subwoofer enclosures, is there anything that I missed? Why such a length discrepancy between WinISD and the person who designed the enclosure for me?
Thank you to anyone that can help 🙂
Being that I had certain size constraints, the external dimensions of the enclosure with 0.75" MDF would be 12"W x 12"L x 28"H with a slot ported tune of 25hz. (Downfiring driver)
Using the internal dimensions of 10.5 x 10.5 x 26.5 yields a volume of 1.69 ft3, inputting the internal volume and port dimensions of 1.25"H x 10.5"W, WinISD recommends a port length of 30.36 inches but after reviewing the cut list for the enclosure designed for me, the slot port definitely seemed MUCH longer.
I confirmed that by modeling the enclosure in Sketchup and found out that the port length using the center was 48.76 inches (attached a screen shot)
I'm not really well versed in the art of creating ported Subwoofer enclosures, is there anything that I missed? Why such a length discrepancy between WinISD and the person who designed the enclosure for me?
Thank you to anyone that can help 🙂
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Well, wouldn't have thought it would be that much difference and maybe not, but there's losses when using tight bends, so Googling to refresh my memory turned up lots of info, but no quick reference, though did find this calculator to maybe get an idea or maybe what he used: bend losses in ducts - Google Search
On-Line Duct Friction Loss
GM
On-Line Duct Friction Loss
GM
With those internal dimensions, the slot port can be created with using two sides of the enclosure. I don't get the idea, why they have created such a complex design, if that duct with so many bends is the final result.
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