Tuning my 4th Order

[Subwoofer Stokes]

I have built a 4th order for 3 12" subs. The sealed is about 2.5 cubes and the ported is close to 5. I have a port 5"x18.5 and is tuned to 60hz. Should I lower my tuning a little? What about port area?

[Motorboat KER]

I have built a 4th order for 3 12" subs. The sealed is about 2.5 cubes and the ported is close to 5. I have a port 5"x18.5 and is tuned to 60hz. Should I lower my tuning a little? What about port area?

Wow that is high! Normally I see people doing 40-55hz. I am in the process of building a 4th and I plan on tuning to 50hz. How does it sound for you as it is?

[CleanSierra]

Port area seems low to me. I'm running 4 12s in a bandpass with 260+ inches of port.

It all depends on the subs you're using though. Which subs ARE you using? I also have mine 2.4 cubes per 2 subs. So 1.2 per sealed.

Your lows are going to come from that sealed volume. If you skimp on sealed area, your lows will be sacrificed.

Running is preference though. The idea is to bring the two peaks together between sealed and ported. You have where your sealed side starts to roll off on its high end(let's just guess 45 Hz). Your ported chamber has an area where it rolls off on the low and high end as well. Let's say you're tuning is 60 and you start to roll off at 50 Hz. That means the music from 45-50 will be noticeably quieter(in this made up scenario).

Does any of this make sense?

[CleanSierra]

Remember though, the lows come from the sealed chamber. Once you tell us what subs you have, I'll let you know if you have enough space or not. You can always stuff the sealed chamber with polyfill to give it the illusion of more airspace.

[Joe X]

I have built a 4th order for 3 12" subs. The sealed is about 2.5 cubes and the ported is close to 5. I have a port 5"x18.5 and is tuned to 60hz. Should I lower my tuning a little? What about port area?

Better post what subs, amp vehicle models you have and pics of the box (and/or a sketch with dimensions), then, what's the problem with your box??