NEED HELP with 4TH Order

[xtremeacoustiks]

would like some help with design of a 4th order, have never done any of them before....

wanna do 8 12" Audiopipe TXX-APX12W's on (2) AP30001D's...have all the equipment just need help with box design

outside demensions are....40" wide X 36" Tall X 30" deep

[HHR Ed]

What is your goal? If going for SPL #s, you may need more airspace.

[xtremeacoustiks]

What is your goal? If going for SPL #s, you may need more airspace.

I will be competing with it some..but would like it tuned around 33HZ....i competed with the same subs this year in meca but i used a sealed wall and highest score I got was 152.6 on the TL...i just wanna try somethin a little different

[HHR Ed]

I will be competing with it some..but would like it tuned around 33HZ....i competed with the same subs this year in meca but i used a sealed wall and highest score I got was 152.6 on the TL...i just wanna try somethin a little different

Bandpass tuning isnt as simple as just stating a frequency such as 33hz.

You tune an F3 down point and and F3 high point. This is the low frequency of where it drops 3dB below the peak, and the high frequency where it drops 3dB below the peak. Thats why it is a "Band Pass" it filters out highs and lows.

Once you have your F3 points, you can plot the frequency curve and find your peak or peaks since there can be 2, and see if it is plotted flat.

Flat is usually the best for SQ, a sharp peak is good for SPL but has a steep roll off.

If you want to peak at 33hz, you need an F3 at 25hz or under, this is very low and the response over 40hz will suffer.

I believe it will be best to try and get it flat from 35hz to maybe 50hz and have a slow roll off on either end.

[xtremeacoustiks]

Bandpass tuning isnt as simple as just stating a frequency such as 33hz.

You tune an F3 down point and and F3 high point. This is the low frequency of where it drops 3dB below the peak, and the high frequency where it drops 3dB below the peak. Thats why it is a "Band Pass" it filters out highs and lows.

Once you have your F3 points, you can plot the frequency curve and find your peak or peaks since there can be 2, and see if it is plotted flat.

Flat is usually the best for SQ, a sharp peak is good for SPL but has a steep roll off.

If you want to peak at 33hz, you need an F3 at 25hz or under, this is very low and the response over 40hz will suffer.

I believe it will be best to try and get it flat from 35hz to maybe 50hz and have a slow roll off on either end.

ok sweet...like i said ive never messed with the bandpass design before..sorta somethin i was wantin to try out....any help is greatly appreciated