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While researching the best speakers, you’re likely swarmed with references to “electrical resistance,” “speaker impedance,” and “Ohm-ratings.” These phrases come with apocalyptic warnings, begging you to buy amps and speakers with compatible impedances. And it’s true; you don’t want to mess up. But to know how to select the best subwoofer compatible with your stereo amp, you must understand the difference between impedance ratings. So to help you, below, we’ll discuss 8-Ohm subwoofers vs 4-Ohm.
The odds are that those looking into speaker systems are debating a dual sub setup. For insight on this, we have a helpful resource discussing two subwoofers vs one. You also may be interested in our article comparing bass tubes vs subwoofers.
Before settling the score between our two types of speakers, we must define what an Ohm is. An Ohm is a fundamental unit of measuring electrical resistance, and electrical resistance explains how much power the speaker can handle. More specifically, it measures how the speaker impedes or resists an electric current.
The two main ways to wire a speaker are series and parallel wiring. Depending on which connection you choose, you can increase the speaker volume.
For this article, the essential rule is that the fewer Ohms, the less resistance, meaning that it takes on a larger electrical current. Here comes the apocalyptic warning: connecting a speaker with high resistance to an amp with low resistance (and vice versa) can overload the equipment and cause speakers/amps to burn out.
Once the concept of impedance is clear, you can see why the Ohm load matters. An 8-Ohm speaker has more resistance than a 4-Ohm speaker, meaning the 4-Ohm handles more power output. The same is true for 2-Ohm vs 4-Ohm subwoofers. So how does this affect how a speaker sounds?
While impedance is probably the most important spec to consider, size is another thing to consider when choosing a subwoofer. To learn about this, we have a size comparison article, 8-inch vs 10-inch subwoofers.
Many variables affect sound quality, but the rule generally goes that the higher the impedance speaker, the more precise it’ll sound. The reason is that a higher power transfer from the amp to the speaker increases the likelihood of distortion.
Monitor how long you’re listening to subwoofers. Speakers with lower frequencies are likelier to cause hearing damage.
Always remember that a speaker with less resistance has a greater volume output. With more electric current a speaker handles, you’ll get a louder sound. So, for the power-hungry, a 4-Ohm output impedance is the correct route.
It’s typical that the lower the Ohm load, the more it will cost. So an 8-Ohm subwoofer will be cheaper. Additionally, you can buy a less powerful amp, which saves additional money.
STAT: There are three main Ohm ratings with speakers: 4-Ohm, 8-Ohm, and 16-Ohm. (source)