I was doing some research and i came across a very detailed article on subwoofers. Newbies, experienced and oldies on this forum may enjoy this article.
WARNING!
This article is
VERY detailed!
Reference:
http://www.iroczone.com/technical/Subwoofer/
Article and Figures by Jim Irace, unless otherwise noted.
Jim Irace
This article is a bit tough because in many cases, especially if you’re building your first system, your subwoofer and subwoofer amplifier will probably be bought at the same time, and your selection of them is really pretty dependant on each other… more so than with other components of the stereo. So, if you’re in a situation where you’re looking for both, make sure to read this and my amplifier article that I didn’t write yet.
This article basically picks up where the "How to buy Speakers" article left off. If you haven't read that yet, at least skim through it and read the section that explains how a speaker works so that you'll have a better understanding of what is discussed here.
So anyway, on with the subwoofers.
Buying a subwoofer is probably the most popular and most rewarding car audio purchase. Nothing transforms your stereo quite like the addition of prodigious amounts of bass. What many people fail to realize, however, is that making your system boom is not the only reason to consider adding a subwoofer. When I used to sell car audio, over and over I’d hear people give me all kinds of reasons why they didn’t want a sub, and it almost always revolved around not wanting that booming bass-heavy drone. What they didn’t know is that I secretly switched their coffee for Folgers Crystals… oh, wait. What they didn’t know was that quite often I’d have a subwoofer playing when they walked into the sound room, and as soon as they’d say something about the boomy bass, I’d shut the subwoofer off and suddenly they’d realize that the music is missing its entire foundation without it. They never noticed that the sub was playing because what they didn’t realize is that bass doesn’t have to be boomy and overwhelming unless that’s how you want it. Properly integrated bass just becomes part of the music, not an addition to it.
Specifications
The actual data provided to a buyer can vary wildly from brand to brand, and even model to model. Most companies will give you somewhat basic data such as power handling, impedance, and perhaps a suggested enclosure size. Others will give you considerably more information in the form of Thiele Small (T/S) parameters. These are the mathematical parameters that represent the subwoofer’s mechanical and electrical properties, and are used to determine many things, but are primarily used to determine proper enclosure specifications.
Power handling
This spec, like most, can mean a lot of different things, but generally you want to find the speaker’s RMS power rating. A peak power rating is worthless on a subwoofer just like on everything else. Power handling on a speaker is a very dynamic specification that’s hard to sum up into just one number. Like I mentioned in the “How to buy speakersâ€