im building a sealed box for my sp4 to see what it sounds like. is it as simple as just making a 23X23X22 box out of 3/4 and a couple lengths of all thread?

Just make sure that the box is braced and whatever volume you want, and go for it.

yeah pretty simple and straight forward.

k, thanks.

 

after i build this one and test it i want to make an octo port box and see how that sounds.    i made my first ported box ever and i think it turned out good but not quite what i expected. i wanted it to just whip things around the car with air pressure but that is not the case. however i think its due to my port being made for music instead of max air flow? 

that takes cone area

you say cone area is what makes the air flow? not the port? how much more cone area would i need from a 18" sp4? i had assumed it would be kind of a given with such a large sub?

1 18 will make some noise and blow some stuff around but I think what your looking for will need more

hmmm, perhaps ill ditch the hair chair part and just go for quality with volume.

Just because it is ported doesn't mean much. Port area and tuning as well as net volume makes a large impact on how it performs.

I have 1 sp4 18 on a sundown 2k and 1 roof brace broke, side window is leaking, and my side mirror is taped and ziptied.

my low end bass is bloody insane! however im someone who prefers the sub xover to be at 150hz as i like the 60-125hz frequencies in my bass. my truck is pretty solid so nothing is breaking but there is quite a bit of flex. in a couple weeks im going to make an octo port box and play with tuning.

did you end up making this?

Octo rofl. Just build a box

i just made a sealed to play with. i now want to try a 4th order. i want to know how a 4th order works and how it sounds so i really want to build one. im making a new post to see if i understand things correctly.

how big was your sealed?  how did it sound?

it sounded flatter than the vented wich was good but it was not able to reproduce the upper highs that my old BL was able to in its higher tuned box. i really liked the flatter response but im not sure if i like sealed over ported, id love to have a ported that could have a bit flatter of a response rate as there are some frequencies that i want to hear louder. im starting ot understand how the sub functions as i play with new boxes.

4th orders generally have a wider playable range than typical vented enclosures despite the "bandpass" name.

 

I can't explain it on a graph as graphs show the opposite of what i'm saying but 4th order BPs are not as efficienct(spl-wise) as a normal vented enclosure but only by some, nothing dramatically quieter.  4th BPs give an overall deeper and higher bandwidth over flat response goal-ed vented enclosures but lose some efficiency when doing so in amplitude.

well it sounds like this is what i am looking for then. the boxes are crazy large tho... like im looking at a good 45% increase in size. not sure how im working this...

how big was your sealed?

8 cubic

why so large?

I wanted to start large and cut my way down to small. just that my sub caught fire before I could finish

what?!

i was going to take the large box and slowly cut .5 cubic out of it at a time and test its response. i wanted to see inside my truck how the acoustics worked progressively.  however my sub caught fire, set fire to my box, and set fire to the roof of my truck cab before i was able to finish this. my recone arrives tomorrow so ill be starting up again then.

i was going to take the large box and slowly cut .5 cubic out of it at a time and test its response. i wanted to see inside my truck how the acoustics worked progressively.  however my sub caught fire, set fire to my box, and set fire to the roof of my truck cab before i was able to finish this. my recone arrives tomorrow so ill be starting up again then.

 

Good luck. I'm personally done with the Sp4 after mine going up in smoke. Took it to another submaker and confirmed it wasn't anything i could have prevented as it was just weak solder/glue joints and over time they just give out and come loose and arc from one to the other. This is all the users fault  though because it is in their eyes either clipped, overdriven, using bass boost, SS set too low, own any of approximately 80% of the oversaturated market of Korean amplifiers, or perhaps live in a climate that has to much change. To know that I could not pound on it for less than 30 minutes every 2 weeks at car shows didn't sit right with me. Just know that you aren't alone.