Square Port Questions

[enemyofsilence]

this is probably a noob question but how much square port are should i have for a dc lvl 4 18? and what is square port volume displacement? i have been trying to figure it out but i would like some clarification. thanks.

heres a sketch of one from re website that i may use.

[OBI]

Correct me if im wrong but, if your talking about square port area then for a lvl 4, 90-100in^2 would be fine. The square port volume displacement is just telling you how much room your port is taking up in your box(its showing it in inches).

[Neo_frog]

You can't just 'know' the sq in of port area only knowing the sub.

First off, if you used the RE calculator and you like what you see as far as tuning (Fb) and box volume (Vb), then just build it based on the cut sheet they provide.

If you're doing it yourself, find out how much space you need, calculate port size and tuning where the 'port area' is 12-16sq in per cu.ft. of volume, calculate the port displacement and adjust the box size as necessary. (All in design phase) Then start building. (This is why ppl use the calculator)

Port area - cross-sectional area of port opening ("inner" measurements). Length x Width in square units. Should be 12-16 sq.in. per cu.ft. of volume.

Port displacement (or 'square port volume displacement') - volume of port including port walls (outer measurements) - Length x Width x Depth in cu. units including the wood used to build it. This is usually used to calculate net box volume and tuning.

Hopefully that's easy enought to understand.