Car: 2008 Scion xB (Think miniature Mini-van)

Amp: Sundown SAZ-1500D

Goal: Daily beater

Music: Mostly rap

Ok, in the trunk, I've measured out space for a box about 17x38x13.5 (LxWxH), about 5.05 cu ft.

Now my dilemma is choosing a subwoofer. With my space and power, I could do either one BL or two SSDs.

One BL15: 2.8-4 cu ft

-Flatwind & Cooling

-Power handling: At least 1500 watts

-Driver displacement: 0.18 cu ft

-Efficiency: 90.7dB 1W/1m

Two SSD12: 3.6-5 cu ft

-Flatwind

-Power handling: At least 1600 watts

-Driver displacement: 0.28 cuft for both

-Efficiency: 85.3dB 1W/1m

I'm trying to decide which one might get louder. More cone area vs. higher efficiency is my dilemma. I know there are a lot of factors that will influence this, but anything will help.

I've tried to give as much information as I could, so if theres anything else that might help you help me, ask me.

Mahalo

~Trevor

I would go for 2 12's. More cone area.

trevor i'd do the SSd's

check your PM too i forgot about something to tell you

Got the PM Abunai, thanks, will check it out.

Well, it looks like the SSDs might be happening.

If anyone else has anything to chip in, go for it.

Ok, in the trunk, I've measured out space for a box about 17x38x13.5 (LxWxH), about 5.05 cu ft.

Are those external dimensions? If so, you have less than 4 ft^3.

You going ported, or sealed?

These are indeed external dimensions. This is going to be a ported box, tuned to around 32Hz, hopefully.

Okay, so I was playing around with the box calcuator (http://www.soundsolutionsaudio.com/home/index.php/boxtools/291-boxtoolscat/96-sideport-box-calculatorflash) and you can put in two different lengths for the port. I can get my desired tuning of 32Hz by using different combinations of height and width. Is there an advantage to using a long and wide port over a short and narrow one? I'm guessing wind noise comes into play, but not exactly sure how that works.

No one?

you should keep the port area an 8:1 ratio and keep the port more vertical than horizontal. Someone on here a while back stated that but i do not know why.

I am unaware of the effects. I am dumbfounded on that part of the topic.. i am completely stumped, i am...

I'll quit typing.

ratio of 8:1 or less. vertical or horizontal doesn't matter, because flip the box and horizontal becomes vertical, ha.

The reason for not having a long, narrow port has to do with surface area. The more rectangular a port is, the more surface area it has, and thus more resistance to air flow.

Ku

sorry i didn't get the more surface area part...

2x8 port has 16" surface area...

4x4 port has 16" surface area...

Am i missing something here or i misunderstood your post maybe...

the 8:1 ratio is to keep port noise down (or scuffing) to a minimum...

Oh, I mean surface area inside the port. Not port area at the opening.

Maybe try and think of it as a lot of 2D rectangles that make up the entire port length. In your example, a 4 x 4 port would have a perimeter of 16 inches. similarly, that 2 x 8 port has a perimeter of 20 inches. That extra 4 inches gives more surface area inside the port, which gives more resistance to the air trying to flow through it and more area around the port opening. Some port noise comes from the difference in pressure between the air coming out of the port and the air that immediately surrounds the port opening. The port air has to kind of curl back around at the port opening to try and fill in the low pressure area. Kinda the same principle with the mirrors in your car as you go down the road and why sometimes you can hear noise from them. High pressure in front of the mirror, low pressure immediately behind the mirror. This is why rounding port openings helps with port noise. Instead of having a sharp corner that allows that little low pressure area to be created because of the 90 degree corner in the wood and the port air wants to continue to go straight (while still applying pressure to the port walls and wants to go outwards laterally as well), the rounded port doesn't allow for that little pocket of low pressure because the air can immediately go laterally once escaping the port.

As you keep getting a wider but less tall port, the surface area inside the port increases. So another way to get 16 sq. inches of port area would be 10 x 1.6 (23.2 inches of rectangular perimeter) or 16 x 1 (34 inches!) Does that make sense?

laminar flow is the terminology that shizzon was looking for. it has to do with how air along the port walls will slow down and heat up compared to the air running down the middle. smooth vs turbulent. while i understand the how, i can't explain the why, so like shizzon, i'll quit typing, lol. but do indeed google the term.

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee