Sub displacement

[eabg55]

Hi, I´m building a ported box for 2 EX series2 12" subs, it will be

3 cu ft tuned to 35 hz, but i need to now how much airspace do

these subs displace so I can build my box at the exact dimensions

I planned it, I will be using a MTX 250D amp. Thanks

[Kim]

If the enclosure has a internal volume then tune the enclosure to
40 Hertz ( 39.89 Hz. to be exact ). This will require using ( 2 ) 4 inch ports ( I.D. ) and cut them to 10 inches in length. This will allow for greater bass response because of the increase in output at this tuning frequency. You can tune them to 35 Hertz by using ( 2 ) 4 inch ( I.D. ) ports that are 14 1/2 inches long but you will lose some of the "impact" from this tuning frequency. Have fun and experiment!!! The vent air velocicity when using the 10
inch long ports is only 16 Meters per second at 300 Watts input power, and for the 14 1/2 inch long ports it is reduced slightly to 15 Meters per second. This does include the displacement of the drivers in these calculations for this enclosure.
Hope this helps.

Happy Porting!!
Kim, Polk Audio

[eabg55]

I have also thought about tuning at 40 hz, but isn´t 40 hz a

high tuning frequency, because I have read about the unloading

characteristic of ported boxes, so I think this could damage my

woofers. Am I right or tuning to 40 hz should be fine.

Or what about going sealed, will this improve dramatically the SQ,

will the subs still hit hard and which enclousure is more

recommended if I go sealed.

Thanks again.

[B2Bomber]

I'm thinking of inverting my mm2084s, does anybody know what's the displacement for these subs? tia.