Since there are always loads of subwoofer setup questions floating around I thought I would share some of the best information I have found on the topic. Hopefully this will help others model output curves that fit their needs and get away from some of the poor "manufactures suggested" installation guidelines.
Be prepared to be blown away! Some of the common "truths" will be shattered.
This is the best explanation of box dampening I have ever read, please enjoy. Short and simple. This will help when modeling drivers in WinISD and you will see the correlation between port length / box size and how it directly effects cone excursion! Clipping and over excursion are the two best way to kill a perfectly good sub-woofer. Also note that some polyfill can do wonders in smaller boxes to make them "sound" larger.
Clip from Adire Audio:
Just because a driver is rated at 1600W does not mean it NEEDS 1600W, or that it can handle that 1600W in your application! How much power do you need? In many situations, 200-400W is plenty. Do not over-estimate what you need! You can easily get loud enough to cause permanent hearing damage with a Brahma 12 in a 1 cubic foot sealed box and 600W of power. If you value your hearing, and want to simply have a sub that sounds great, then be judicious about the amount of power you’re going to use. Use the power you will actually need, not what you think you want.
Thermally, Brahma can take a lot of power. Mechanically, it depends upon the box and application. The larger the box, the LESS power is required to reach a given SPL level. The system – box and driver – becomes more efficient. For example, a Brahma 12 in a 1 cubic foot
sealed box will reach full Xmax at 1300W at 20 Hz. In a 2 cubic foot sealed box will require around 800W to push full Xmax at 20 Hz. In 2.25 cubic foot ported and tuned to 30 Hz, 500W will reach full Xmax at 20 Hz. Choose your power based upon your application! Too much power doesn’t gain you more output, but can easily destroy your subwoofer.
Once again: a power rating is just that – a power RATING. It is NOT a requirement, or recommendation of power! You only need as much as your application requires and can safely handle; more power is the quickest way to destroying your subwoofer, and definitely constitutes
abuse. If you’re not sure how much power you need, ask around, or use a good modeling program like WinISD Pro (not the regular/original version – the Pro version is what we want!) or other accurate modeling tool that shows excursion of the driver, and look at the results. If the
excursion breaks 50-55mm peak-to-peak, you’re pushing it too far.
TS Parameters Explained:
2007 Cadillac DTS: AT400.1 + 15" Brahma
Daughters 2003 Saab 9-3: In progress!
1979 Porsche SC: Kenwood X-994, PG M50, PG RSd comps.
1971 Chevy C-10: wind noise