port area ?

[alaskanzx5]

so i know that 12-16" of port per cu ft of box is a general rule of thumb. my question though is more port area better or worse for spl? i read in a thread on here that a box tuned to 32hz that had just over 16" of port per cu ft wouldnt help play low becuase of to much port area.

so does a bigger port area help with spl while a smaller port area helps with playing lower freq?

[RAM_Designs]

With a smaller port you're going to have a smoother roll-off below tunging, in most cases. A woofer with a stiffer suspension will also keep it from unloading below tuning easily. All in all, you have to take into consideration what sub you're using, what freqiency range you want it to excell at, and build around that while taking what you know about your cabin gain into consideration as well.

[alaskanzx5]

Im gonna be getting 2 rockford t2 15 and I want more of a daily setup and im not worried about winning any comps but I would still like to get a decent score for the build. On my last 2 builds I used boxes I made using torress and one was tuned at 41 Hz but I didn't pay attention to port area because I didn't know anything about it but still managed a 143 at 48hz with a single RF t2 12 runnging on a 15001.1bdcp at 2 ohms. With the second box tuned at 43 Hz,just under 16" per cu ft with 2 t2 12 with the same amp I did a 146. My first 2 setups was using pre Fab boxes and those peaked at 51hz one with was with a single 2 12 and one was with 2 t1 10s boxes where tuned around 38 hz from what they said but thats all i know.

With the build going into a 03 Ford focus 4 door hatch back and wanting to be able to play songs that get decently low ( lower then 30hz like my last box ) down to about 25hz while still being able to achieve a decent score of around 146-147 at or around 45 Hz using 2 t2 15s and my t1500.1bdcp would tuning around 33-35hz with a higher port area be able to do it or would it be better a little lower?

sub specs power handling 1200rms 2400peak

fs 31hz

re 6.8

le 2.06

qms 5.49

qes .69

qts .62

vas liters 51.6

sd cm 750

xmax 22.38

spl 86

gonna be taking out the back seat to do this with the box as far to the front as possible with the seat still in a position that is comfortable. unless i would have better luck with it closer to the hatch then i could mount my amps and batteries closer to the seat but i was gonna try to place the sub amps to where the port pushes air across them, my dimensions are 39 wide 20 heigh and 45 deep.

any help that anyone could give me with a good daily box that can still do decent number with the info giving would be great.

I know this is a harder question to answer and there are a lot of different things that have to be accounted for but any help is great.

[TeamHT]

Let me see if I can type concisely from my mobile phone. When I had more port per ^3 I noticed the enclosures were peakier and peakier. Which might explain why people might say it works better for SPL, since frequency response doesn't matter when competing on tones.

I always thought, to get strong ground pounding air movement, I wanted to tune low and give it heaps of port. And every design I did worked great but then I started to realize the lower I tuned, the less port I wanted to give it. It allowed me great frequency response, and sounded better getting lower, and louder and lower frequencies. Huge ports look sexy, but we get older and wiser lol

[TeamHT]

Are you set on RF subs? I love me some RF subs, but what I've realized is when they're in low tuned enclosures, their upper response is near nonexistent. And when tuned at daily listening, their low end response rolls off rapidly.

You know, josh at North Coast is the Alaska AA rep

[kalilac619]

Let me see if I can type concisely from my mobile phone. When I had more port per ^3 I noticed the enclosures were peakier and peakier. Which might explain why people might say it works better for SPL, since frequency response doesn't matter when competing on tones.

I always thought, to get strong ground pounding air movement, I wanted to tune low and give it heaps of port. And every design I did worked great but then I started to realize the lower I tuned, the less port I wanted to give it. It allowed me great frequency response, and sounded better getting lower, and louder and lower frequencies. Huge ports look sexy, but we get older and wiser lol

couldn't agree more Lol

[DubNDodge]

Let me see if I can type concisely from my mobile phone. When I had more port per ^3 I noticed the enclosures were peakier and peakier. Which might explain why people might say it works better for SPL, since frequency response doesn't matter when competing on tones.

I always thought, to get strong ground pounding air movement, I wanted to tune low and give it heaps of port. And every design I did worked great but then I started to realize the lower I tuned, the less port I wanted to give it. It allowed me great frequency response, and sounded better getting lower, and louder and lower frequencies. Huge ports look sexy, but we get older and wiser lol

With this being said, would you mind looking at a box design for me? I have 10"sqin per cube. I know its supposed to be 16" But from reading what you just said it seems ok do to do this. Heres the link if you don't mind. http://www.stevemeadedesigns.com/board/topic/153899-confirm-this-box-design-2-sdc25-12s/

[TeamHT]

What speakers you use also plays a huge part into enclosure, response, and performance.

[alaskanzx5]

yeah im set on the rf subs, i want it to be an all rf build. i know that the prefab box i had one of my t2 12 in was tuned to 38 hz and played good daily but was still just a little to peaky so im hopeing that with the 15s in a box tuned to about 35 hz will be better. i actually really like the sound of my 2 t2 12" in the box i made tuned to 43hz with just under 16" per cuft of port in a 4cuft box after displacement. my only proplem is songs that played down into the 25-30hz range wasnt where i wanted it and around 25-28 hz i had to keep the volume down a good bit to keep it from bottoming out. i mean i wasnt overpowering them with the 1500.1bdcp and the box at 4cuft from my understanding would have been on the smaller size with underpowering them.

i never plan on over powering the 15s so a box right around 5.5-6cuft should be effecient for them and if a smaller port area can give a better freq response and allow me to play down lower and that combined with a lower tuning the the 40-43hz ive been tuning at for spl should be able to play 25-45hz fairly well then right?

so a box tuned to 35hz with about 14" of port per cuft with a volume of 5.5-6cuft after displacement with only 750 watts per 15 or if i sell my amp and get something else to give them at most rms i should be able to play down to the 25hz and up to 45hz with anything from 30-40hz having more authority behind it?

[caraudiolove]

so how do you figure out you have 12-16"' of per cubic ft?

do divide the port area by 2 if you have 2 12's?