Bridging 8 ohm subwoofer

 

Bronze Member
Username: Mmmg

Post Number: 11
Registered: Sep-05
Hi, Sorry for the long post
I need some advice in upgrading my audio system. What will happen if i bridge an 8 ohm subwoofer. Let us say the amp provides 100 wrms@4ohm...so if i bridge 8ohm sub to this channel will the subwoofer be driven at 200 wrms. I have a cheap quality 4 channel amp made by power acoustik. I want to upgrademy system..so i want to buy a new amp. My budget is limited to $150-$200. So i want to use the present amp and a new amp. I heard some ppl bridging the channels to connect component speakers. But i gues bridged channel provides a mono signal which is useless for a component speaker. Is it so..I have two plans. One is bridge the two 8ohm subwoofer i have to the existing 4 channel amp using all the channels. the amp says it provides 100 wrms@4 ohm and 125 wrms@2 ohm. So if i bridge 8ohm i guess i will be providing 200 wrms to each sub.And buy a two channel amp for the fron speakers. Second option is connecting the subwoofers to a new 2 channel amp and use the old amp to power speakers(using just two channels among 4 channels). Or else get a new 4 channel amp and dump the old one..Most ppl will say that i shuld just dump the old one but my budget is limited so i cannot get a good 4 channel amp for that budget.. and i dont want to waste my old amp.
plz give me some best options..thanks
 

Bronze Member
Username: Mmmg

Post Number: 12
Registered: Sep-05
sorry for the double thread
 

Silver Member
Username: Tdisanto

Post Number: 113
Registered: Sep-05
"the amp says it provides 100 wrms@4 ohm and 125 wrms@2 ohm. So if i bridge 8ohm i guess i will be providing 200 wrms to each sub.And buy a two channel amp for the fron speakers"

You need to tell us what the bridged specs are. (XXX wrms @ 4ohm x 2)

Second, when impedance goes up power goes down.
P = V^2/R

So you would want to wire the 2 8ohm subs in parallel (giving a net impedence of 4 ohms) and then wire them to the amp in a bridged configuration. The amp will then provide half of the bridged power spec to each sub.
 

Bronze Member
Username: Mmmg

Post Number: 13
Registered: Sep-05
thanks for the reply......the amp says it provides 250w rms@4ohm X 2. I am already connecting the subs as u have mentioned. But if the 8ohm subs briged over the 4 channels i guess it shuld get 200 wrms each.(bcos when we bridge 8 ohm over two channels i guess its sees the load as 4 ohm..so 4 ohms over two channels which will yield 100+100=200 w rms for each sub) idont know if this is true.genrally good amps double the power when impedence is halved.but for this amp its just 25% increse in power when impedence is halved. So i want to bridge these 8 ohm subs to four channels. i am guessing i will get 200w rms for each sub if i use all the available channels.......thanks
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