Audio Express Understanding Electrical Resistance

Understanding Ohms and Why They Matter in Your Car Audio System

We’ve all seen the word ohm, or the symbol Ω, when shopping for speakers and amplifiers. But what exactly does it mean, and why does it matter?

Ohms represent impedance on the audio signal from your amplifier to your speakers. So the lower the impedance, the more signal can travel from the amp to the speaker.

To give a visual explanation, think of the speaker as a pipe, the audio signal as water and the amplifier as the pump. The wider the pipe, the less impedance there is for the water to move through it.

Balance of Power

Audio Express Understanding Ohms

The reason this is important for your car audio system is because you want to make sure that speakers and amplifier can handle each other’s power, and the ohm load matches correctly. If your amplifier is more powerful than your speakers, you can burn out your speakers.

Conversely, if your speakers have a lower impedance than the rating your amplifier, the amplifier will end up working too hard, and either burn out or shut down in protection mode, to avoid burning out. Many lower quality amplifiers do not have protection circuitry, and could potentially cause a fire in the event of too low of an ohm load, so always make sure you purchase a quality, name brand product. Either way, it hurts your audio system, and could potentially be dangerous.

If you want to run two Alpine SWR-12D2 subwoofers in your car, then you will want to find an amplifier that meets its overall 2-ohm rating, since these woofers are dual 2 ohm voicecoils. The JL Audio RD1000/1d Mono Amplifier would be a perfect match, or if you want to run just one Alpine SWR12D4 woofer, the Alpine MRV-M500 Mono Amplifier would be a great choice, as it will put out a solid 500 watts of RMS at 2 ohm.


Audio Express Understanding Ohms

While this is pretty straight forward, it does get complicated when dealing with a multiple speaker system and the variety of different wiring options. Wiring speakers in series, which means one speaker is wired from its negative to the other speaker’s positive, the impedance is doubled – so two 2-ohm speakers wired in series have a total impedance of 4 ohms.

However, if the speakers are wired in parallel, meaning they are wired positive to positive and negative to negative, then the total impedance becomes the impedance of one speaker divided by the number of speakers. Two 2-ohm speakers wired in parallel end up with a total impedance of 1 ohm.

Because of these variables, it is important to have an experienced professional install your new amplifier and speaker system. Our professional installation technicians will install your system to optimize sound quality and prolong the life of your equipment. Many times, ohm’s law gets confusing for people, and 1 ohm is very close to a potential dead short, which could always cause electrical issues, so it’s best to keep the overall ohm load at 2 ohms or above.

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For more information, stop by one of our convenient Audio Express locations, and talk to one of our trained car audio professionals. If you want to know more without leaving the house, you can always Ask Liu. And remember: We offer the lowest install prices available.

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