Question for box builders

weapon-X · Postby **weapon-X** » December 3rd, 2015, 9:59 am

So, I'm getting ready to add some bass to my SUV. My main issue is space in the trunk.

Now. I've designed the box I want to use in the trunk space I have, so I have to make sure also, that the box volume matches the sub I choose. On to the question...

Why is it that two subs of equal power, require two different size boxes? The two subs i'm comparing are below.

DS18 SLC-8S, 8'' Sub. This needs a 0.89 ft box, and
Rockford P1S4-8, 8'' Sub. This needs a 0.65 ft box.

I know the punch is the better quality sub, but why would the cheaper sub ask for a larger box?

Sully · Postby **Sully** » December 3rd, 2015, 12:13 pm

The box size isn't proportional to the cost. It's a function of the subwoofer parameters.

weapon-X · Postby **weapon-X** » December 3rd, 2015, 12:47 pm

I understand. Thanks for the help.

On another note, I know that ported will always perform better than sealed, but is the difference way off?

Soundstream_626 · Postby **Soundstream_626** » December 3rd, 2015, 6:58 pm

It all depends on what response you want. every manufacturer`s optimal tuning is different. some companies like DD and Pioneer recommended enclosure is tuned to 40hz others like RE recommend 34hz. Sometimes they dont tell you the tuning, just build a box x cuft with x port.

The vas qts and fs of the sub in question will determine what is "optimal" for a particular enclosure. Things that determine these factors include suspension stiffness, moving mass etc. try modeling the ts parameters in win isd.

In general my experience with sealed subs, for my personal taste, they could have used a bit of boost under 35hz, but then you`re gonna get into excursion limits etc when you tinker with that kind of thing.

Brian Steele · Postby **Brian Steele** » December 4th, 2015, 12:21 am

Sully wrote:The box size isn't proportional to the cost. It's a function of the subwoofer parameters.

...and the marketing department of the subwoofer's manufacturer ;-)

Brian Steele · Postby **Brian Steele** » December 4th, 2015, 12:26 am

weapon-X wrote:I understand. Thanks for the help.

On another note, I know that ported will always perform better than sealed, but is the difference way off?

Ported systems will have more output at low frequencies (above Fb) than sealed systems, but then they "unload" below Fb. And the required vent length increases substantially as Fb goes lower.

You won't find a ported box that can produce 3 Hz tones :-)

Roughly, if the driver can produce an Fb/F3 combo around 40 Hz in a sealed box, then it may be best to use it in a sealed box for car audio duty. Otherwise you may want to consider a ported box.

weapon-X · Postby **weapon-X** » December 4th, 2015, 11:43 am

Yo guys, thanks for the help and info. I got a bit more of a technical explanation from another 2nr.

He said the box is bigger, because the DS18 sub is a high excursion output sub, even with the low rms rating.

Ted_v2 · Postby **Ted_v2** » December 4th, 2015, 6:48 pm

LOL.

quick question why a 8"? a single 8 never impressed me, a single 10" ported is the smallest sub ill ever put in a vehicle.

Pirate · Postby **Pirate** » December 4th, 2015, 8:52 pm

An 8" in a properly sized box sounds great. You will not get the output of a 12 but for the space it cant be beat as a compliment to a stock system.

meccalli · Postby **meccalli** » December 5th, 2015, 7:08 am

Agreed, a single re8 or jbl gto sounds amazing in the right enclosure. Just right.

Sully · Postby **Sully** » December 5th, 2015, 11:29 pm

weapon-X wrote:Yo guys, thanks for the help and info. I got a bit more of a technical explanation from another 2nr.

He said the box is bigger, because the DS18 sub is a high excursion output sub, even with the low rms rating.

Well that's totally incorrect. Xmax isn't a variable when calculating enclosure size, especially if it's a sealed enclosure.