4th order, thoughts?

[ncc74656]

sp4

i have never built a 4th order. I have just built my first ported box not long ago and now i want to try this. id like some help in understanding the parts that i am not failure with.

[ToNasty]

what woofer is this for

[ncc74656]

Fi, SP4 18, i suppose i should add: my goal is to get good lows and highs. i want the killer 32 hz range while at the same time being able to have the 65hz ranges at the same or close to the same volume. i want to minimize peaks in frequency response wile also keeping a very high output volume.

[ToNasty]

well id go a 1-3 ratio, id do 3 sealed, 9 ported. to be honest im not understanding what your doing in torres,

[ncc74656]

the torres is just for the ported side of hte box. my intention is to tune the ported side to 45hz to allow for higher frequencies while retaining the sealed side for lows. from what i read the higher in ratio you go the more spl and less highs you get. is this accurate?

the 2-1 ratio i selected was an effort to achieve this.

[ToNasty]

that means that your sealed side is 6 cubes, way way to big, do 3-3.25 sealed and go from there, and if you want spl then go 1to3 ratio

[ncc74656]

my sealed is 4.43. i think my primary goal is to get a wider range of frequency with as much volume as i can so with that in mind i think i want to strike a balance between quality and SPL.

in this application what is the trade off here? a smaller sealed will give me X where as a larger sealed will give me X but take away Z?

a larger ported with a smaller sealed will give me X but a smaller ported and a larger sealed will give me Z?

how large of a port is needed for these boxes? i hear they must be much larger than a normal vented box. is my port on this box large enough? if i go larger i cant seem to work out how to keep a lower tune...

[ToNasty]

You lost me.

[ncc74656]

thats fine, i might have lose myself long ago.

so im looking to flatten my responce curve while retaining as much volume as i can. my ideal setup would be able to play 30-90hz with little peaks, be so loud that you need to time your breathing with the music, and move enough air to make a hair box in the cab. that said with a single sub it seems i can not make a hair box as thats what i tried with my current one and it failed.

i have had a BL and a SP4 in there own boxes with low and high tuning and i prefer the higher tuning but i really do want to get lows as well. my current SP4 box give amazing lows but is basicly a SPL at the 34hz range and drowns out every thing else. it also does not have the crisp sweeps of bass im looking for.

so i designed this 4th order with a middle of the road sealed (per mfg specs) and double the sealed size in a vent. i do not know if it matters what direction the sub faces? i do not understand the corilation between making one side of the enclosure larger or smaller so thats what im asking. from what i read the smaller the sealed box the higher it will want to play and the larger the box the lower it will go. couple that with a 2:1 ported and you also get highs.

also from what i read the port must be very large as all the sound comes from it. it must be considerably larger than a normal vent in the range of 1/3-1/2 of total SD of the woffer. to this end im not sure if my port is large enough on this box.

the box is built with 1.5" wood so thats why its not a 6cubic box like you thought but a 4.43 box.

thoughts?

[ncc74656]

i noticed an issue, i did not have proper ratio between the 2 boxes. here is an updated math sheet on the vented side of hte box: