Quote Originally Posted by sleepyantz View Post
Ask lang din ako regarding sa box. according to the manufacturer's minimum volume for ported box design is 1.75 cu ft, my current box is around 1.0 cu ft, how would it affect the sound of my bass or would it improve the sq or spl or anything, if i had a bigger box. My initial plan was to have 2.5 cu ft ported box based on manufacturer's maximum recommended volume, however the installer made otherwise. Im really new to this car audio thing, i had only researched as much as i could and this is my first hand experience with this.
The Rockford Box wizard will only tell you how to construct your box. Computing your ideal box on the otherhand needs more parameters.

For quick calculations, I like DIYAudio's box calculator: Speaker Box Enclosure Designer / Calculator

As you can see there, there are a few parameters you need to throw at it. The more important ones are the Qts and the Qtc. If I were to summarize it, these are subwoofer parameters that will tell you whether your subwoofer driver is designed for sealed or ported enclosures and what will the optimum box design and volume you will need. The Fb is the ported tuned frequency.. this is the frequency where the ported box is at its loudest -- a very common frequency is 38hz.

Okay, ano ang negative effects if you constructed the box wrongly? Alot of stuff really as your subwoofer performance is highly dependent on its enclosure. You see, you're not really required to follow the manufacturer's specifications because (in these ported box scenarios) your box volume will differ depending on its tuning. If your manual is wanting 38hz and your installer wants to tune it higher and make the box smaller, that's his call.

What would a bigger box usually get you? Efficiency. If your subwoofer cone's maximum one-way travel (remember that your cone bounces up and down during music playback) is achieved with 500W of power. Making the box larger will make you achieve the same output with a lot less output.. let's say 200W.

Hope this helps,
Kevin