When talking about subwoofers, we usually come across the word ohm (symbol: Ω). But what does it actually mean? Why is it important and why do we have 2 ohm and 4 ohm subwoofers? In regard to quality, subwoofers will have a recognizable difference in loudness and even durability because of their varying impedance (resistance offered by an electric circuit of alternating current A/C). Regarding pricing, brand will always be a factor but usually 2 ohm costs a little bit more.
2 ohm Subwoofers
When talking about ohm (international system of unit of electrical resistance) in regard to subwoofers, it mainly involves how much power it can accumulate and transform into sound. Generally with lower electrical resistance, (in this case the 2 ohm subwoofers), it will produce a louder sound. Although it might be louder than subwoofers with higher resistances, it may however produce a lower quality of sound due to the power consumption.
Depending on the size of the subwoofer and brand, a 2 ohm subwoofer is normally priced from $50 up to $200.
4 ohm Subwoofers
With 4 ohm Subwoofers, they would have a higher electrical resistance and would then produce a less loud sound in comparison to the 2 ohm subwoofers. Also, since power consumption is less, it could also mean that it will last longer compared to subwoofers with lower impedance. Having the said electrical resistance, it will also produce a more compact sound that may mean a better quality sound.
Depending on the size of the subwoofer and brand, a 4 ohm subwoofer is normally priced from $20 up to $180.
Technically, they differ in only just a few things and that’s how much resistance one can get, how much power will pass through your subwoofers, and of course how much dB (logarithmic unit to measure acoustics) they can produce. Just note that with these subwoofers, it’s better to connect them with their corresponding amplifiers with the same impedance.
To explain further, let us say you have two subwoofers, one being a 2 ohm and the other a 4 ohm. With your 2 ohm subwoofer at 2.83 watts, it can produce 93 dB, your 4 ohm subwoofer will then have 90.5 dB at the same wattage. With a difference of 2.5 dB, it will be noticeable if you’re an audiophile but if not, it actually is not that big of a deal.
Now for the sensitivity, i.e. the quality of sound it produces, let us say the 2 ohm subwoofer will be at 86.4 dB at 1 watt and for your 4 ohm, 86.6 dB with the same wattage. Now at .2 dB difference, this actually is a very slight difference. The 4 ohm subwoofer may technically be producing a better sound quality but in truth, it won’t have that much impact.
So to put it simply, the difference is not that great if say you are planning on having a few subwoofers. It will mostly produce the same sound if they are run at the same wattage and will make little difference to the sound produced, the main difference being maybe the price.
|2 ohm Subwoofer||4 ohm Subwoofer|
|Produces a louder sound (having the same wattage)||Produces a softer sound (having the same wattage)|
|Produces a slightly poorer sound quality||Produces a slightly better sound quality|
|Costs more than 4 ohm (brand prices vary)||Costs less than 2 ohm (brand prices vary)|
|Lower electrical resistance||Higher electrical resistance|
Here is a video to explain the impedance of a subwoofer in relation to its wattage.