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Can someone explain how running equipment at different OHMS affects the system?
Which is better, a high OHM system or low OHM. Which plays louder? Also, how do you actually change the OHM output of a brigeable amp?

thanks guys
 

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The single most important thing about impedence (measured in ohms) is that the speaker impedence matches the the amplifier. If an amp is designed to drive an 8 ohm impedence, you ideally want to hook 8 ohms up to it, if it's rated at 4 ohms, you want to hook 4 ohms up to it. It is safe to connect a larger impedence than what the amp is rated for, but it won't play as loud (lowers the power output, measured in watts). Connecting a lower impedence than what the amp is rated for can ruin the amp.

I've never seen a car amplifier that has selectable impedence. Sometimes you will see 2 power ratings for different impedences but thats just to tell you what power you will get if you connect speakers with one of those impedence ratings. For example, if you have an amp that's rated at 100W @ 4ohms and 40W @ 8 ohms, that means that it can handle a 4 ohm load and will deliver 100W, or you can connect an 8 ohm load and get 40W.

When you bridge an amp, the effective load it sees changes because of the way the speakers are connected. There is no "ohm output" that you have to select. Some amps have a switch to select bridged or normal mode but many also switch automatically so if you don't have a switch and you're sure it's bridgable, you just hook it up (follow the amps instructions).

So, basically, to get the most power (volume) without damaging you amp, connect speakers with the lowest ohm value that the amp is rated for in the mode you're using.
 

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To add to what gdavis said, ohms has a lot to do with a system. And even more to do with subs. If you have an amp that will put out 100W @ 4ohms, and 50W @ 8ohms, yes, the 4ohms will run more power, but it will also push more Amperes. Which means the wires must be bigger, and puts a bigger load on your cars electrical system. If you see an amp rated at 2ohms, or even 1ohm, yes, it will put out more power, but it will also require a lot bigger ( thicker ) wires into and out of the amp. Running more amps through an amp will also make it get hotter. All this is a big consideration when designing a system for any car.
 

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<i>Can someone explain how running equipment at different OHMS affects the system?
Which is better, a high OHM system or low OHM. Which plays louder? Also, how do you actually change the OHM output of a brigeable amp?</i>

Neither is better. www.teamrocs.com is a good place to start for info. If you have specific configuration questions post them to this thread...

Ted
 

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Actually, a high ohm system (say 8 ohms) would be theoretically ideal if you had the power to support it. Better headroom,, lower distortion, less strain on componentry, etc. However, in practical applications, a system designed generally around the 4 ohm barometer will more than suffice.

Do bear in mind that ohms are not nearly a fixed measurement; they change with frequency, musical dynamics, etc. A sub rated at 4 ohms can measure a resistance of anywhere between about 3-20 ohms during musical transients.
 

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Just to confirm this: I ran my Genesis V speakers off my Sonic Frontiers Power 2 Amplifier for 2 years at 8 ohms. The speakers were nominally rated at 6 ohms. Last year when I switched tube drivers in the amp, I switched the output coils to 4 ohms in the amp just to take a listen. HOLY SHIT. The difference was extremely signifigant. The noise level was signifigantly higher and highs actually made you wince (Genesis V use ribbon tweeters). The sound stage was also shifted a good two to three feet closer to me, and it was more compressed. Very strange!


>Actually, a high ohm system (say 8 ohms) would be theoretically >ideal if you had the power to support it. Better headroom,, >lower distortion, less strain on componentry, etc. However, in >practical applications, a system designed generally around the 4 >ohm barometer will more than suffice.
 

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Home audio is a lot more picky than car audio I've found. I've actually took a scope and measured the output of my PPI A600.2's all the way down to 1 ohms stereo and the difference in distortion is negligible, if non-existant. However, I must note that the PPI amps have rollback circuitry that optimizes the ohm-age (is that word?) of the load to the output rails of the amp. The amp is 2 ohm stereo optimized (max power putput) but you can run it at 1 ohm stereo and it just puts out only have the power, 1/2 ohm is 1/4 power, 1/4 ohm is 1/8 power, etc. It doesn't care.

Bottom line, in the noise filled enviroment of a car you'd be hard pressed to even hear 1% THD let alone 0.02% .vs. 0.04%. Home is a different matter, as well as competitions were the "prestiage" of using certain brands outways the actual sound quality they may produce.

That's why I refuse to participate in IASCA until they do the sound judging BEFORE they inspect the systems. ~8-10 years ago it was basically winning = MB-Quart/PPI/JL Audio/Audio Control. Not quite so bad now but still....


Ted
 

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tb, somethings you just can't measure. :) i did a double blind test once against (2) $1000/6 meter cables. I could easily tell the difference between them. doubt it all ya want. :) but i'm an EE too.
 
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