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post #1 of 7 Old 03-08-2013, 08:42 AM - Thread Starter
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Please tell me how this design makes sense. Any sense.
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Unibox indicates that there would be only 2% reduction in linear excursion with this woofer in down firing orientation. With that in mind, below is a 240 liter box, net volume, no stuffing, with a quad array of down firing Dayton RSS210HO-8 eight inch subwoofers wired series of 2 x 2 in parallel, with a 2 Ohm resistance in series with the array, and with four AE 18-inch 2100-gram passive radiators (one per side), Unibox shows the following. Peak current is less than 10_amps, so using that figure, power through the 2_Ohm series resistance should be less than 200_Watts-peak at X-linear excursion limited output. Adding stuffing softens the tuning at the bottom, would provide some rolloff to compensate for room gain in smaller tighter rigid walled rooms. The excusion limit shown is set at 98% (not visually any different than 100%, but there it is).
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post #2 of 7 Old 03-08-2013, 10:28 AM
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Sounds like a .... passive radiator design.... with four 8's and completely overdoing it on PR's.

Unless I'm missing something. confused.gif

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post #3 of 7 Old 03-08-2013, 10:39 AM
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Not bad, actually. I would do it differently but ... the results are pretty decent.

EDIT: woops... made a mistake... brb.


EDIT 2: Sorry, accidently modeled it with only two passive radiators. Lol, I think it was better that way. tongue.gif






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post #4 of 7 Old 03-08-2013, 11:53 AM
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Quote:
Originally Posted by djkest View Post

Please tell me how this design makes sense. Any sense.
It makes none from a cost standpoint. The four eights have a combined Vd of 1024 cc and a cost of $432 plus the cost of the PRs. A single RSS 460HO has 1484cc Vd and costs $250.

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post #5 of 7 Old 03-08-2013, 11:55 AM
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Exactly. I don't see the point from starting with nothing but who knows? Maybe whoever is building this had the parts laying around. *shrugs*

I certainly wouldn't have gone about it this way coming from nothing. I'd use other gear. However it is a working design.

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post #6 of 7 Old 03-08-2013, 12:46 PM
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Quote:
Originally Posted by Scott Simonian View Post

Exactly. I don't see the point from starting with nothing but who knows? Maybe whoever is building this had the parts laying around. *shrugs*

I certainly wouldn't have gone about it this way coming from nothing. I'd use other gear. However it is a working design.
As soon as I see someone using series resistance an alarm goes off, telling me that it's a guy who has gone too far over to the purely theoretical side of things. Yes, in theory you can use series resistance to alter Q, but in practice it seldom has any benefit.

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post #7 of 7 Old 03-08-2013, 01:23 PM
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maybe it is a design to try and keep it thin to go behind or under something?

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