8 ohm subwoofer on a 2 ohm amp?

modernwar99

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Jul 9, 2014
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I have an old JBL Music 1 passive subwoofer and it needs an amp to be used with my modern Harman Kardon A/V receiver. I was stupid and bought a 200 watt single channel amp rated at 2 ohms. My subwoofer runs at 8 ohms and needs a 10-200 watt amp. Based on my understanding I could run a 2 ohm amp with an 8 amp subwoofer, but it wouldn't output 200 watts at 8 ohms. I don't want to open the box in case I need to return it, so can I use a 200 watt amp rated for 2 ohms on an 8 ohm subwoofer, and if I can, how many watts will the amp put out at 8 ohms?
 
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Ok first thing don't come to toms for audio help unless its headphones/headsets/headphone amps/cheap PC speaker crap.
Second i can help a bit 1 it doesn't need to output lots of watts...

jdwii

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Apr 13, 2010
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Ok first thing don't come to toms for audio help unless its headphones/headsets/headphone amps/cheap PC speaker crap.
Second i can help a bit 1 it doesn't need to output lots of watts since 100 watts isn't 10 times louder than 10 watts. Also you can use 8ohm speakers on lower ohm amp nothing is wrong with that but you can't do it the other way around.
 
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modernwar99

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Thank you, I'll try it out. Also I know that there aren't many experienced people in audio on this forum, but I didn't want want to sign up for a forum dedicated to audio for one thread. I figured since I already had an account here, I might as well make a thread.
 

jdwii

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I understand that man and you can always PM there is some expert audio guys here just not a lot and nothing compared to AVS fourms or anything
 

lemon07r

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Mar 11, 2010
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Run your speaker sub setup in a parallel circuit (daisy chain it) and the impedance will be
FormulaResistorParallel01.gif
So your total impedance will [most definitely be lower then 8 and] depend on the ohms of your speakers (which are usually actually even lower then what they are labeled as). This is under the assumption you are setting it up using only a the high lvl input connectors.

I had a similar issue, had a 4-8ohm amp and 2ohm amp, and 8 ohm speakers. So I just ran it in a series (amp to sub to speakers) using only the high level in (my sub didnt have a high level out). So in theory its a 10ohm circuit, but probably less then that cause like i said before, most speakers have less impedance then what is labeled on the back.

Links to look at for a better understanding:
http://www.prestonelectronics.com/audio/Impedance.htm <(This one is really good)
http://www.sengpielaudio.com/calculator-paralresist.htm