Type R 12 Ported box (help)

[rawmaterial]

29 width
16 height
19 Depth

i am not sure how to measure the port but they are sharing the same air space.

my question is, i listen to all rap, lil john music! would this be enough air space for my two alpine type R 12's? just going for SPL vrs some of the frens

[jellyfish420]

if that is your external measurements. with a 14.5x3"port 44"long @30Hz. will leave you right around 2.5^ft...but if all you want is spl then i'd go 14.5x5" 22"long @49Hz. that will leave you around 3^ft. but if you like to listen to lil john then going higher than 30 either a)if you got your ssf set right you wouln't hear any bass or b) your gonna rip your sub apart.

[rawmaterial]

if that is your external measurements. with a 14.5x3"port 44"long @30Hz. will leave you right around 2.5^ft...but if all you want is spl then i'd go 14.5x5" 22"long @49Hz. that will leave you around 3^ft. but if you like to listen to lil john then going higher than 30 either a)if you got your ssf set right you wouln't hear any bass or b) your gonna rip your sub apart.

wats the main difference like sound wise with those two ports?

and when you say going higher then 30 what are you talking about? and what is ssf? thanks for your help!

[jellyfish420]

the bigger port tuned higher will yeild higher spl, but will not go as low. the smaller one tuned lower will not have quite the spl, but will go much lower. tuning freq of the box, i perfer not to do anything over 35, but most of my boxes are 30Hz. and the SSF is you sub-sonic filter on your amp...it filters notes under a certain frequency.

[rawmaterial]

Most of Lil Jon's bass is in the lower-to-mid 30s, so tuning high would be counteractive to what he wants ...

so i should build a port that is tuned to 30? and the box i mentioned shares air space is that a good thing or a bad thing?