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So backstory: built a wall shaker in my college dorm days with help from here (thanks!), but now I'm married and in a tiny-*** Northeast US "apt" (really a converted house). 6.4cuft behemoth had to go, but I kept the parts. I convinced myself I was going to build a 3cuft sealed and be happy with it, but became aware of the marty sub... after I already got a 3cuft flat pack. ****.

So now I'm stuck with this and trying to make it marty-like, ie same tuning/driver as the mini. That's where issues came up. At max power, to keep port speed down (using L-R 4th order 20hz HPF) below 17m/s I have a few options:

(A)Use four 3"x11.5" round vents
(B)Use two 4"x20" round vents (requires cutting off part of brace so driver can be shifted up, can't fit while centered, and internal 90 degree shift to accommodate length)
(C)Use four 2"x3" slot vents
(D)Use two 2"x6" slot vents (same requirements as B).

So two questions. First, can (D) be simulated by combining equivalent areas in an L shape like on the left so driver remains centered? Second, would shifting the driver off center of bracing as in (B) or (D) have any negative effects? I assume not because it seems like a common design, but just making sure.

Thanks in advance for any help
 

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  • Yep I believe you can keep port tuning the same via cross-sectional area and length for the volume of the cab.
  • The 17 m/s ROT I believe comes from a 3" or 4" round port, smaller ports need even lower velocity and larger ports (and flared ports, IIRC) can handle higher velocity without audible chuffing.
  • There is no ill effect of not having a sub driver centered, that is your aesthetic of choice.

Good luck and be sure to share results!
 
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