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New member Username: RinobrinPost Number: 1 Registered: Aug-05 | I ran into an article that had me stumped. The article suggests: " If you wire two 8-ohm speakers in parallel, you are creating an ohms load of 4 ohms (8 ohms x 8 ohms divided by 8 ohms + 8 ohms = a 4 ohms load on the amplifier). If you connect two 8-ohm subwoofers in a parallel hook-up to an amplifier that is bridged mono, the amplifier will see half of the load because it is bridged. So it will be seeing a 2 ohms load." My problem is with that last part. Why would an amp that is wired with a four ohm load only see half the load and run at 2 ohms? I think an amp wired for a 4 ohm load will run at 4 ohms. This article suggests otherwise. The correct information regarding which load a bridged amp will see will directly affect which model amp I decide to buy so it is important to me to get the record straight. The articles URL is http://www.ehow.com/how_5829_wire-car-stereo.html the quote can be found in the 2nd "tips" area halfway down the page. I think this article is wrong but I'd like input from other's before purchasing my sub amp. Thanks :P |
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Silver Member Username: Iowahawks19Post Number: 394 Registered: Jun-05 | haha i had the same exact problem, I talked to subfanatic about it awhile ago and he explained it very well, your correct, a 4ohm load will still be a 4ohm load, but the amp puts out more power because it "thinks" its a 2ohm load, talk to someone who knows more into it, but if the amp says(ex)"2x400w rms @2ohms and 1x800w rms 4ohms mono it's KINDA like the same thing, but not really BTW, bridging an amp only helps if your running the amp to 1 sub! if you have 2 subs, just run the subs of each channel, it'll be the same |
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Gold Member Username: GlasswolfWisteria, Lane USA Post Number: 9014 Registered: Dec-03 | because bridging the amplifier uses the positive and negative voltage rails of the power supply to get full power to one channel of the amplifier when inverting one of the two stereo channels. it's explained here: http://www.bcae1.com/bridging.htm |
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Gold Member Username: GlasswolfWisteria, Lane USA Post Number: 9015 Registered: Dec-03 | PS the article is completely correct in a sense. the amp doesn't actually "see half the load" per se, but that's the easiest way to put it if you don't understand how an amplifier power supply functions. The end result is pretty much the same. an amp puts out the same power into both channels combined at 2 ohms stereo, as it puts into one channel at 4 ohms bridged. You don't actually get "more power" bridged, but you get all of it into a single 4 ohm load, which helps with a single sub. |
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New member Username: RinobrinPost Number: 2 Registered: Aug-05 | Thanks Mike and GlassWolf. The link you gave was a good read. Now I know way too much about bridging an amp and why it sees a different ohm rating. I have a 10" JL W6 DVC with 2 ohm voice coils. I can run it @ 1ohm or 4ohms and I did't want to wire it for 1 ohm into a bridged amp and find out my amp got fried because it was seeing a 1/2 ohm load. I think if I ran the DVC's in series at 4 ohms then bridge the amp it will run at a stable 2ohms. The amp is stable for 1ohm bridged @ 800 watts RMS which would probably melt my voice coils so running it in series the amp puts out 400rms bridged at 2ohms which would be perfect. Thanks again :P |