12 inch subwoofers for big bass
12 inch subwoofers are the entry level sized subwoofer into big bass. It’s true that you can get an 8″ or 10″ subwoofer to give you nice clean and responsive bass line, however if you really want to feel the music, without resorting to drugs, meditation, or the ‘high’ of playing live on stage; then your only resort is going to be a hard hitting sound system that brings the music alive, and part of a hard hitting sound system, besides ultra crisp highs and liquid midrange is a punch, responsive and very present bass line. I think it comes as no surprise for me to tell you that 12 inch subwoofers are the 5th highest sold car audio product online due to their impressive performance.
If you think about it simplistically, how hard 12 inch subwoofers (or any size subwoofer for that matter) hit is related to two things really:
1- The size of the subwoofer, that is to say , when the subwoofer moves forwards it pushes air creating a pressure wave and making sound. The amount of air the subwoofer moves per stroke is proportional to the surface area of the moving subwoofer. In this sense, a single 12″ Subwoofer has more than 2.5 times the area of a single 8″ subwoofer and that makes it move at least 2.5 times more air per stroke. Therefore a pair of 8″ subs will never hit as hard as a similarly designed 12 inch subwoofer, all other factors being equal.
2- On the other hand, we have to consider the volume of air being moved in total for the complete woofer cone stroke. This volume of air, especially if we’re talking about a sealed enclosure design, is going to be equal to the area of the subwoofer face multiplied by the length of its stroke.
The length of the subwoofer stroke is how far forwards or backwards the subwoofer moves with the bass signal. The maximum displacement (typically called xMax) is a measurement of the maximum distance the sub can move from its original position to move air and create sound waves. The key here is that the larger the subwoofer is in its diameter, the easier it is for it to have a larger displacement without really stretching or stressing the body and surround material of the subwoofer.
 SVS 12 inch subwoofers |
Think about it in terms of triganometery for a minute. For a 6″ subwoofer to move 2″ in forwards displacement means that the shape of the subwoofer body would have to be seriously distorted and and become an almost cone shaped triangle with a 42 degree inner angle. If we were to allow the subwoofer body to be flexible enough to distort like this then it won’t be able to transfer enough energy into the air because the subwoofer’s body would rather warp (being soft to allow for a higher displacement) than it would push the air forwards to create sound.
On a larger 12″ subwoofer though, a 2″ displacement is a very small angular motion for the subwoofer, a displacement angle of only 19 degrees compared to a massive 42 degrees for a 6″ subwoofer.
This means that larger subwoofers, for example 12 inch subwoofers, are not only able to move more air for a similar stroke, but typically we’ll find that they’ll also have a much longer stroke or max displacement enabling them to hit even harder than a PAIR of smaller subwoofers.
In order to take advantage of this phenomenon, we’ve seen in the last few years manufacturers make subwoofers that have a stiff center section (capable of effeciently transferring the subwoofer’s kinetic energy from the subwoofer’s body and into the air), with a thicker flexible surround section sometimes 1″ or even 2″ thick. This thicker surround portion allows the subwoofer to have a greater max displacement to produce louder bass. However, to get the best quality and best response out of this kind of system requires a higher power rating amplifier.
Here is a great video showing the excursion stroke of a pair of 12 inch subwoofers in a vented box. You can also see the amount of air these babies can move. This is truly the entry level into BIG BASS!
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