What Do Ohms Really Mean?

[sungwei 10+ year member]

I know ohms is resistance to the flow of electricity. But what does this mean for car audio? I always though less was better, but apparently sometimes people want more ohms. Why is this? How do people use this spec?

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[Acidburn 5,000+ posts]

for car audio its mainly to figure how much power an amp will put out, the reason you would want more ohms is if the amp is not stable down to one ohm then you need to use two or more ohms

 

[homer3304 10+ year member]

yes ohms is the resistance to flow of electricty, so if you have a high number there will be no flow at all. If you have a direct short like a wire across the 2 terminals the resistance would be close to 0 ohms. So if you have an amp that is not built for lower impedance of 1 or 2 ohms definitely dont use it there or you smell stinky fumes coming out of it.

 

[sungwei 10+ year member]

HOw can you tell how stable your amp is? I'm going to be using an xtant 403a that has 4ohm and 2ohm ratings. The sub I'm using is a 2ohm sub. Is it sometihng to do with wiring? Is more or less ohms necessarily better or worse?

 

[adam71 5,000+ posts]

HOw can you tell how stable your amp is? I'm going to be using an xtant 403a that has 4ohm and 2ohm ratings. The sub I'm using is a 2ohm sub. Is it sometihng to do with wiring? Is more or less ohms necessarily better or worse?

Check the specs in the owner's manual or if that is too vague, call the mfg.

Adam

 

[maylar 10+ year member]

HOw can you tell how stable your amp is? I'm going to be using an xtant 403a that has 4ohm and 2ohm ratings. The sub I'm using is a 2ohm sub. Is it sometihng to do with wiring? Is more or less ohms necessarily better or worse?

The amp will have ratings for power with different ohms load. If the amp specs 4 ohm and 2 ohm numbers then it's usually safe to assume you can't go any lower than 2.

More or less ohms is insignificant in the overall scheme of things. The important part is to match the impedance (ohms) of your speakers or subs to the capabilities of the amp.

High ohms are easier for an amp to handle. The lower ohms your speakers are the more power they draw and the more strain they put on the amp. Zero ohms is a short circuit.

Every amp has a limit to how low it can go. That's what they mean by "1 ohm stable", etc... it's the lowest impedance load you can use without causing problems.

Power (watts), voltage (volts), current (amperes) and impedance (ohms) are all related mathematically. It takes more voltage to make the same power with high ohms than it does with low ohms. In home stereo systems voltage is not an issue, and 8 ohm speakers are standard. In car systems voltage is 10 times less so speakers tend to be lower impedance - 4 ohms is standard, and 2 ohms is common for high power stuff like subs.

HTH

 

[sungwei 10+ year member]

Maylar, that was an excellent explaination. Thanks. I really understand it now. So I guess I'll be ok. The 403a has a 2 ohm rating of 100 x 2 and 200 x 1. Very good info.