Two-way (car speaker)
Music can be reproduced with reasonable accuracy by two-way, or coaxial, designs. These speakers use a separate crossover and tweeter to deliver high frequency reproduction that surpasses that of single cone or dual-cone "extended range" models with whizzer cones. The tweeter, usually a cone or a dome, is mounted either on a post or bridge inside the front of the woofer cone. While our illustration shows a 6X9 oval speaker, the design is readily available in most oval and round sizes.
Three-way (car speaker)
Three-way or triaxial speakers take the separate woofer and tweeter from a two-way design and add a dedicated midrange driver for enhanced coverage of the vital middle frequency area. The filling effect of this extra mid-frequency energy can also boost overall uniformity.
Four-way speakers add a small "super tweeter" to extend the high range frequency response out to 22 to 25 Kilohertz, This is not so advantageous as it might seem. Very few people can hear sounds above 15 Khz, and in a relatively noisey car environment, such sounds could easily be obscured by road and ambient car noise.
Bridge & Post Mounted (2 & 3-way speakers)
In combined 2 and 3-way speakers, which have woofers together with a Tweeter, or a Tweeter and a Midrange driver, the smaller drivers are attached to the woofer by either one of two standard mountings:
The bridge-mount method has a metal or plastic bridge running from one side of the woofer's outer perimeter to the other. The smaller driver or drivers, together with the crossover network, is then mounted on the bridge. The advantage of this arrangement is that the woofer center dome is left intact with no exposure of the voice coil or other internal elements. On the negative side there is more covered surface area that marginally reduces the output at certain frequencies, and it may be little more difficult to mount the unit.
The post-mount method provides a post that is attached to the center of the inner magnetic pole, to which the other drivers are then mounted. It has a reduced obstruction to woofer dispersion, but it can require a hole in the dust cover/cap that could give environmental access to the woofer's inner workings. This creates the possibility of operational degradation from accumulations of dust over time, unless a flexable cover is provided.
Component Speaker Systems
This term is used to indicate a system in which separate mounting arrangements are provided for each component of the system. In a typical car system, you might see mid or full range drivers at the side, and tweeters mounted on the dash panel. A pair of crossover circuits delivers separate signals to each driver. In some arrangements, a bass system driven by its own amplifier compliments and completes the system. This compares to the typical integrated speaker enclosure in which all the drivers are mounted in the same box or assembly.