advice needed on two fi sp4 15s

[that1dude]

hi all , im new to the forms and fairly new to car audio until now the nices system i had was back in 2006 with two audio bahn immortal 15s on 2 rub 2500s. im looking to get back into car audio and have a design that I have been working on and was hoping for someone slightly more experience would be willing to go over my design. all help is greatly appropriated

the electrical will not be an issues since i am an electrical engineer i have that covered.

box design though is a slight bit more of a preference then anything, i was hoping for someone to check my math based around these drivers.

2 FI sp4 15s on 8k RMS clean power. this will a SQL type build.

the bracing will be two 1/2inch wooden dowels ,22inches long.

sub displacement, flush mount .24cf

slot port

i will be glassing and sanding the box inside

images upload

[Smoove]

8k , 8 cubes and 144sqin of port is not really sql. It will get down and move a ton of air.

Are you planning on playing stuff like got160's ?

[that1dude]

8k , 8 cubes and 144sqin of port is not really sql. It will get down and move a ton of air.

Are you planning on playing stuff like got160's ?

not really sure who or what got160s is but i am aiming for it be for daily driver and maybe try and hit the meter. daily ground pounder

listen to bass heavy music and moving a ton of air is kinda what i was going for with a decent response down to 30hz and upto 45hz

8k is kinda the low side ive been eyeballing the hcca orion 11000.1d amp and it will be in the back of my blazer

[Smoove]

8k , 8 cubes and 144sqin of port is not really sql. It will get down and move a ton of air.

Are you planning on playing stuff like got160's ?

not really sure who or what got160s is but i am aiming for it be for daily driver and maybe try and hit the meter. daily ground pounder

listen to bass heavy music and moving a ton of air is kinda what i was going for with a decent response down to 30hz and upto 45hz

8k is kinda the low side ive been eyeballing the hcca orion 11000.1d amp

What vehicle ?

[that1dude]

8k , 8 cubes and 144sqin of port is not really sql. It will get down and move a ton of air.

Are you planning on playing stuff like got160's ?

not really sure who or what got160s is but i am aiming for it be for daily driver and maybe try and hit the meter. daily ground pounder

listen to bass heavy music and moving a ton of air is kinda what i was going for with a decent response down to 30hz and upto 45hz

8k is kinda the low side ive been eyeballing the hcca orion 11000.1d amp

What vehicle ?

sorry yeah its a 99 4x4 blazer

[Smoove]

So are you planning sub up / port back ?

[that1dude]

So are you planning sub up / port back ?

So are you planning sub up / port back ?

sup up/port up facing the roof, it will sit behind the back seats.i have an available space of 30"x28"x38" HxDxW

[Triticum Agricolam]

Here are my thoughts:

1. 1/2" dowels aren't going to provide any bracing in compression, only in tension. When using dowels I wouldn't use anything less than 1.25" in diameter.

2. A 36" wide X 4" tall port has a really high aspect ratio, which is inefficient. Changing your port layout to get a lower aspect ratio would be best, if you can't do that I'd suggest increasing port area.

3. 144 sq in of port area is a bit on the low side for how much power you are going to be running, this is especially true with your high aspect ratio port. I'd run more port area if it were me.

4. At 36 Hz, your tuning is a bit high by most people's standards, your output may start to roll off below 40 hz, you may consider tuning lower depending on what type of music you listen to.

[that1dude]

Here are my thoughts:

1. 1/2" dowels aren't going to provide any bracing in compression, only in tension. When using dowels I wouldn't use anything less than 1.25" in diameter.

2. A 36" wide X 4" tall port has a really high aspect ratio, which is inefficient. Changing your port layout to get a lower aspect ratio would be best, if you can't do that I'd suggest increasing port area.

3. 144 sq in of port area is a bit on the low side for how much power you are going to be running, this is especially true with your high aspect ratio port. I'd run more port area if it were me.

4. At 36 Hz, your tuning is a bit high by most people's standards, your output may start to roll off below 40 hz, you may consider tuning lower depending on what type of music you listen to.

that's very helpful thank you. i can do larger dowels np, what would you suggest for port area and tuning? closer to 200in of port area maybe lower tuning like 34hz wouldn't that put the -3db drop around 26-27hz?

[Smoove]

more like 30-32hz