For music enthusiasts, a good subwoofer is essential to making their music boom when it is supposed to. Adding a subwoofer is a worthwhile investment for anyone who wants to upgrade their old music system, or for someone who is putting a brand-new system together. The subwoofer itself is designed to play sounds in the lowest range of music, and the quality of subwoofer can make a significant impact on how that sound plays.
While there are some great deals out there on used subwoofers, it is important for any potential buyer to know what they are getting themselves into before making a purchase.
What Is a Subwoofer?
A subwoofer is a speaker that plays the lowest-frequency sounds typically found in music. Specifically, these frequencies range from 30Hz to 1kHz. Every subwoofer is built using a cone that is surrounded by magnetic coils. When audio signals reach the coil, the coil creates sound, which is then amplified by the wood cabinet most subwoofers are made of.
Different Types of SubwoofersWhile the basic design of a subwoofer is fairly simple, there is more than one way to create one. While many inexpensive subwoofers use a small bandwidth to create bass, the more expensive subwoofers (and the ones desired most by audiophiles) utilize a wider bandwidth. One of the biggest disadvantages of a high-bandwidth subwoofer is the large amount of space that is needed to house the components and the vibrating air inside the subwoofer housing.
The following are some of the major subwoofer design types:
Band-Pass Cabinet DesignThe band-pass cabinet subwoofer uses a sonorous, tuned box in which most of the sound escapes through one or more ports. This design is typically used in inexpensive home theatre systems and in some car stereos as well. This design is efficient, loud, and ideal for something like a movie explosion, but it’s not very good with musical notes and can sound ‘boomy’.
Reflex DesignThe reflex design has a wider bandwidth than the band-pass cabinet design and can be housed in a mid-sized enclosure. Many mid-range theatre and studio systems use this type of subwoofer. It is not too big and is very efficient, but the driver is not hidden inside the cabinet.
Enclosed DesignThe enclosed subwoofer uses a sealed cabinet to create very high-quality sound. However, this design is very inefficient and can put strain on the driver and the amp. This design also tends to be more expensive than other subwoofer designs.
Transmission Line DesignTransmission line subwoofers are a combination of reflex and enclosed design and have many of the benefits of each. Transmission line subwoofers are very easy to align and integrate into an existing system, and the sound is particularly accurate. The only downside to this design is the cost, which is often substantially higher than the other designs listed above.
Subwoofer SpecificationsThe following are a few things every buyer should look at before purchasing a used subwoofer.
FrequencyFrequency is the measurement of frequencies a subwoofer emits in terms of hertz. Average subwoofers range from 20 to 200Hz.
Voice CoilsMost audiophiles prefer dual voice coils, as these are more flexible when wiring to an audio system.
Parallel Wiring OptionParallel wiring uses dual 4-ohm voice coils to send a 2-ohm load to the amplifier. Parallel wiring produces the highest output from an amp.
Series WiringSeries wiring allows multiple subwoofers to be configured to one amplifier. Both coils can reach 8-ohm impedance. Series wiring is widely considered one of the best ways to wire a system.
IndependentIndependent wiring is for buyers who do not want to bridge an amplifier. Each voice coil is wired separately to its own amplifier channel.
ImpedanceImpedance refers to the resistance of an electrical circuit relative to the AC flow. In general, lower resistance means higher output from the same power level.
Peak Power and RMS PowerPerformance of a subwoofer is measured by its root mean square (RMS) plus its peak power. Buyers should compare the RMS rating with the amplifier. Too much or too little power can cause damage to the subwoofer.
How to Buy Used Subwoofers on eBayeBay makes it easy to find high-quality used subwoofers, as well as other deals on audio equipment. To find equipment, all a buyer needs to do is search for a specific component, then specify ‘used’ or ‘new’ in the options on the left. From there, a buyer can select from brand, model, power level, and a number of other specifications.
A high-quality subwoofer is an important part of any respectable sound system. While the best subwoofers are not cheap, there are often great deals on eBay, especially if one is willing to look at used options. It is also important to understand how the subwoofer works, and what type of subwoofer will best do the job before investing in one.