Car Audio Subwoofers
Subwoofer Types: Round, Square, and Octagon Subwoofers.
With so many choices to choose from when picking subwoofers, where to start? Subs come in every shape, size, and specification. Besides the obvious differences in terms of diameter subwoofers are available in a large variety of shapes besides the classic round. We will take a look at some different examples and the advantages of each type. First we will take a look at some of the common terms you will find when looking at subs.
Definitions: RMS / Peak Power - Frequency Response - Sensitivity
The first and most noticeable specification you will see is RMS and Peak Power. This essentially rates how much power the subwoofer can safely handle. The RMS power refers to how much power the subwoofer can handle on a continuous load. The Peak rating refers to brief burst of energy that only lasts a second or two, the most important factor to look at is the RMS rating. When matching up subwoofers to an amplifier you would compare the RMS power of the two and want the RMS ranges to roughly match. It does not have to be exact but the closer the better. So for example if you have an amplifier that is rated at 500 watts RMS. You would want a subwoofer that is rated the same, or if running two subs each subwoofer should be rated at 250 watts RMS.
Second is Frequency Response. This is the rating that determines the musical note range the subwoofer is able to play within. The human ear is sensitive to a frequency range from about 20 Hz to 20 kHz and subwoofer frequencies are found from about 16 Hz to 500 Hz. A general rule is: the larger the cone area, the lower the frequency response. At the same time if you are using a subwoofer with a large cone area you will lose higher frequencies, so you would want to choose a subwoofer for your listening style.
The last major specification that needs to be considered is Sensitivity or Efficiency. This will determine how effective the subwoofer is at converting the power (watts) being fed into it from the amplifier. So for instance if you take an amplifier that is rated at 1000 watts and you take two 12” subwoofers in which one of them is rated at 88 dB and the other is rated at 92 dB the subwoofer with the higher sensitivity rating will be louder than the sub with the lower rating.
When looking at subs they are generally available in 8”, 10”, 12” and 15” with other various sizes available depending on the brand. The best place to start when deciding what size subwoofer to run is by looking at your vehicle and determining how much space is available for a subwoofer box. We recommend first choosing an enclosure for the vehicle first and THEN decide on which subwoofer to run. Obviously if you have a regular cab truck it would not be possible to run four 15” subwoofers so you need to choose a box that will fit within the available space. All subwoofers also feature a recommended airspace range for various style enclosures, it is important to stay relatively close to the recommended range. An example would be if you were to run a large SPL rated subwoofer in an enclosure that does not have enough airspace you would actually damage the woofer and it would not perform correctly.
Once you have determined how much space is available for an enclosure you can then determine which subwoofer size to choose. In general the larger the subwoofer cone the lower it will be able to play. So a 15” subwoofer may be able to play as low as about 20 Hz where as an 8” subwoofer will play down to about 30 Hz. The advantage to a smaller size subwoofer is the response will be faster. A 15” cone will have to travel further and has more surface area to move than an 8” cone so it creates a slower bass response time. This will not be noticeable in every type of music but anything with very fast beats such as techno or rock it is actually possible to hear the difference. Normally 10” and 12” woofers work well for all around types of music and are by far the most popular.
The last feature we will look at the actual shape of the subwoofer. The most common shape found is Round. Every car audio brand has their own version and style of a round subwoofer and has the advantage that most car audio enclosures and equipment is built around that specification. Square subwoofers which were patented by Kicker are a relatively new technology and offer a better frequency response than a round subwoofer of the same size. For instance a 10” square solo baric subwoofer will have the same frequency response as a traditional 12” round sub. By going to a square design sub you gain about 20% more surface area. Hexagon subwoofers combine the technology of both square and round subwoofers and feature a better frequency response than a round sub.