Box Rise?

[Bean]

I finally got around to clamping my amp and realized I had alot of box rise(around 2.5). I was wondering if anyone here had ideas of how to control this and how to get this down were my D2 sub can see more power at 1 ohm. For your information, I have an AQ HDC3 18 D2 in a removable port box tuned to 33 Hz on the daily and around 40 for the competition. Any help will be greatly appreciated.

[MrSkippyJ]

What is your box rise a the frequency you burp?

[Bean]

the total rise is 3.5 at 45Hz so with the amp at 1. I assume the box is rising 2.5.

[bkolfo4]

If it is tuned at 40 and burpIng at 45, you are more than likely still in the spike above the tuning frequency.

Your issue is that the burp may have a high impedance, but you may be ok at some frequencies with the lower tuning and playing music.

[skittlesRgood]

a larger box will have more rise but its more efficient. just the opposite for a small box. when i did my testing i found that the larger box made up for the loss in power from rise. if i made the box smaller, my score went down.

just pointing out that imp rise is not the only factor to worry about.

[Bean]

bump for more help

[bkolfo4]

What do you want to know?

If you think you need more power, get a bigger amp or recone the sub as a Dual 1.

Changing the box design may make a difference, may not. Depends on the actual design and what frequency you are burpIng at.

[plissner7]

Very good question here BEAN. I would like some help too keeping my rise down. How do we plan and build to fight this?

[bkolfo4]

Unless you are burping or bass racing music, the BEST thing to do is not worry about it (PERIOD)

Even when I competed, impedance did not factor into my box design. You design the box based on what you need from the subs. Then you select an amp that has enough power to do what you want it to. . .or take a chance and run at a lower impedance load than the amp is rated for.

[skittlesRgood]

^^ totally agree. and like i said earlier, efficiency can easily be better than low imp rise. thats sometimes how a sub can supposedly take so much more power than rated. you build an efficient box but it has lots of rise. put a 5000w amp to the sub but after rise it only sees 2000w. just as an example.