Suggestions for 2 SA-12 D4 REV.3 encloure

[BassNewb]

Max Dimensions:

• Height: 21"
• Width: 35"
• Depth: 15"

Amplifier: Skar SK-2500.1D at 1 ohm

The car will be 2013 Hyundai Veloster, So I would prefer subs up and port back. Unless anyone thinks there is a better option.

I would prefer a slot port and a tune of 30-34 Hz; my goal is lots of low end while still keeping somewhat decent output on the higher stuff, if possible.

If a decent size port is possible (say around 15-16 per cube) I would like that as well.

I am open to any suggestions on this. This will be my first time building an enclosure lol.

Any help would be greatly appreciated.

[Joe X]

If you want port back you will need more than 15D.

[BassNewb]

Would going with less port area perhaps make a difference? The goal with the depth I provided was to be able to put my back seats up. If need be, I wouldn't necessarily mind having to keep them down, doing so would give me 19D or so. I'll measure that later to know for sure.

[BassNewb]

20D with seats down.

[Patrick Bateman]

Here is the frequency response of two enclosures for the SA-12 D4.

The black line is a four cubic foot tapped horn. The folding for the TH is like the first picture.

The grey line is a two cubic foot vented box.

Looking at the response, we can see that the tapped horn delivers quite a bit more output between 40 and 80hz, but as we get to the tuning frequency of 35hz the vented and the tapped horn are about equally matched.

In the real world, I'd expect the tapped horn would be quite a bit louder, because the vented box has a 6" port, while the entire tapped horn is basically a port. The tapped horn will suffer from less port compression. The tapped horn also has the advantage of exposing the magnet to the air, so there's less power compression. The reason that the vented box has that drooping response from 40-80hz is because the woofer has quite a bit of inductance. The TH suffers less from it because the TH naturally has a rising response, so the two offset each other. (The rising response of the TH offsets the falling response of the woofer which is due to inductance.)

But the tapped horn is about twice the size, so that's pretty big.

Here's the excursion of the two designs. They're both tuned to the same frequency, so excursion is similar.

I modeled the design with 2500 watts into a one ohm load, with the voice coils wired in parallel. There's a Linkwitz Riley 4th order highpass set at 26hz and a lowpass set at 80hz. DO NOT RUN THIS THING WITHOUT A HIGHPASS YOU WILL DESTROY THE WOOFER. If you use a highpass, you're not even close to the excursion limits of this woofer with 2500 watts into 1ohm.

Here's the hornresp model of the tapped horn

Here's the hornresp model of the vented box.

The vented box size and the woofer parameters were sourced from the sundown website.