Downfiring subwoofer - benefits ??? - diyAudio
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Old 9th March 2004, 07:26 PM   #1
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Default Downfiring subwoofer - benefits ???

I am planning to build active subwoofer with 2 Westra SW300-2808 drivers in bassreflex box. I saw that many subwoofers that I can see in stores have drivers on bottom side of the box. What are the benefits of that kind of construction (except more SPL), and how can I calculate the right distance from the floor ? Does more distance means deeper bass because of more added mass of air in front of the speaker, or what ?

And one more thing. If bass is on the bottom side of the box, should the port also be on that side of box ?

Thank You in advance for any answer given.
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Old 9th March 2004, 10:01 PM   #2
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AFAIK, it's mostly cosmetics and provides protection for the driver. There may be some acoustical benefit but I suspect it's minimal.
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Old 9th March 2004, 10:04 PM   #3
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Don't think there are any discernable acoustic improvements, but you'd definitely understand why they exist if you have babies and small children underfoot.
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Old 9th March 2004, 10:53 PM   #4
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http://www.adireaudio.com/tech_paper...rientation.htm
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Old 9th March 2004, 11:46 PM   #5
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One other advantage, especially with lighter subslike sonosubs, is the mechanical forces of the driver work against the total weight of the sub. So, instead of rocking back and forth, itjust jumps up and down!

Pete
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Old 10th March 2004, 12:14 AM   #6
sreten is offline sreten  United Kingdom
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With two drivers you should horizontally
oppose them IMO, to allow force cancelling.

Port towards the floor has some adavantages,
but complicates simulation results.

sreten.
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Old 10th March 2004, 01:06 AM   #7
Bull is offline Bull  United Kingdom
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I thought down firing subwoofers was a bad idea with weak motor systems/loose suspension such as rubber.Because the voice coil might shift,and suspension sag.
Not a problem with tight surrounds like cloth and paper and strong motor system though.
Am I right about loose rubber or foam suspensions sag if used in down firing subwoofers and the voice coil can shift???????
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Old 10th March 2004, 01:37 AM   #8
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That's addressed in the article that Luke provided above.
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Old 10th March 2004, 01:38 AM   #9
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Quote:
With two drivers you should horizontally
oppose them IMO, to allow force cancelling.
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Old 10th March 2004, 07:53 AM   #10
Svante is offline Svante  Sweden
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There was a thread about this recently, apart from the immediate sag (gravitational pull) effects there are aging issues as well. One poster had experienced serious long-term sag, which was destructive to the driver.
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