gen II mal-x build - help please

[jsink77]

I got my gen II 18 mal-x last week and I was hoping to get started on the box this weekend. Only problem is that I am trying to do a quick layout here at work to determine the wood I need to get and I am away from my home computer that has win-isd on it. Can somebody please throw these parameter in there and let me know if I am on the right track.

- overall internal volume is 12.3 cu ft
- 2-6 inch ports (the ports are 31 inches long, but measuring to the center of flare at each end, it would make the ports 32.5 inches long) - total volume used should be about 1.24 cu ft
- I do not know what volume the mal-x uses - assuming about .6 cu ft
- bracing will be about .4 cu ft

I am shooting for a tune of 16-17 hz tune in a 25*15 foot room with 8 ft ceilings.

I can adjust the layout and make the internal volume a little bigger if need be (up to 13 cu ft), but based on the feedback I am seeing below, this newer version of the mal-x likes a little smaller box so I am thinking I should be okay.

Can anyone help me out? thanks.

[Mike P.]

If the overall internal volume is 12.3 cu ft then the net volume would be about 10 cu.ft. Two 6 inch ports 32.5" long would tune it to 20.5 hz.

[jsink77]

Does that mean I need longer ports? 35 or 36 - I know they aren't supposed to go over 36 or there will be port noise.

[Mike P.]

The port air speed is in relation to how much power is applied to the sub. Knowing how much power the sub will see will determine the proper port diameter and length. What will you be powering the sub with?

[jsink77]

Sorry - I've been having issues with my computer here at home and couldn't get logged on until this morning. I will be using an ep2500. Thank you for all your help - I am still showing 17.5 hz with a 10.5 cu ft box and a 32.5 inch port so I must be doing something wrong.

[Mike P.]

10.5 cu.ft. tuned to 17.5 hz would make 2 six inch ports 42.8 inches long each.