Question about ohms... please help...

[Justinw303 10+ year member]

I'm very new to the car audio scene, and I have a question. I just called a guy at a car audio place and asked him a question, and his response brought up this question.

Alright, let's say I have two 4 ohm subs (50-200 rms). I also have a 2 channel amp. Here are the specs:

200 watts RMS x 2 at 4 ohms

300 watts RMS x 2 at 2 ohms

600 watts RMS x 1 bridged output at 4 ohms

4-ohm stable in bridged mode

Now, I asked the guy if I could run one sub per channel, seeing as I have 2 subs and a 2 channel amp. Well, he said I would have to run it in bridged mode.

This is where I get confused. He said that since the subs were 4 ohms, it would be running 300 watts to each sub at 2 ohms.

So, does this mean when you bridge an amp with 2 subs you take the ohm rating of the subs and half it to know how many ohms the amp will encounter?

Also, How come he said I could bridge the 2 subs on the amp, and when I look at the specs on the amp the only time it mentions bridging is when it says 600 watts RMS x 1 bridged output at 4 ohms. So, what's up?

And the lowest number of ohms the amp can handle bridged (according to the specs) is 4, so how could I do what he told me to do?

I would really appreciate some help with this. I'm trying to learn as much as I can.

I realize the equipment is cheap, but please bear in mind that I'm a novice.

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[T9X 10+ year member]

Are your subs single or dual voice coil? This tidbit is vital.

 

[Justinw303 10+ year member]

Definitely single voice coil.

 

[Raven 10+ year member]

Attach one to each channel for the optimum configuration of 200 RMS watts to each 200 RMS watt subs. That goes doesn't know what he's talking about.

 

[engineerdude 10+ year member]

yeah-- i wouldn't mess with taht guy-- i don't think he quite understands it.. if your amp can only handle 4 ohms.. then you have to wire each sub to one channel.. that would be 200 W at 4 ohms on each channel.. if you got a second amp you could wire each sub to one amp and each sub would have 600 W.. but that would cost more money..

 

[hondarider 10+ year member]

Or you could wire your 2 svc subs in parallel to get a 8 ohm load and bridge the amp and get 300 wrms to each sub.

 

[Blunt 10+ year member]

Or you could wire your 2 svc subs in parallel to get a 8 ohm load and bridge the amp and get 300 wrms to each sub.

do wha? //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[imaspaceguy90 10+ year member]

Depending if you have dual voice coils, you can change the ohm level of the sub, wich will bring it more or less wattage. Ohms is kinda like a measure of resistance/.

 

[JimJ 5,000+ posts]

A ohm is a measure of a circuit's resistance to electron flow.

Also a measure of an (AC) circuit's impedance.

 

[Eldorado 5,000+ posts]

Where can i get an ohm changer ?

 

[Prowler573 5,000+ posts]

Or you could wire your 2 svc subs in parallel to get a 8 ohm load and bridge the amp and get 300 wrms to each sub.

This is HALF right. He most certainly can wire two 4 Ohm SVC subs in series to achieve an 8 Ohm load.

That is where the correct bit ends.

If the amp's output is 600w X 1channel @ 4 ohms mono bridged and you drop an 8 Ohm load (double the resistance) exactly how do you figure that the amp will then output double its rated power?

Not knowing what brand of amp it is I will assume that the posted ratings are correct for the sake of this discussion. Most (not all, but most) amps are NOT stable lower than 4 Ohms when in bridged mono mode so wiring the two SVC subs in parallel for a 2 Ohm load isn't an option. So - to run these two subs off of a single bridged amp channel (which has been posted as being 600w X 1 @ 4 Ohms) you'd have to wire them in series for 8 Ohms, again - double the resistance - and get approximately HALF of the 600w @ 4 Ohms output....300 watts....or 150 watts per sub.

With the originally posted equipment the best course of action would be to connect each sub to its own channel running the amp in 2ch stereo mode - giving each sub 200 watts.

Subs rated at 200w RMS being fed 200w. Kindof a no-brainer here, folks...

//content.invisioncic.com/y282845/emoticons/slap.gif.87520e8ca8e90076ac30e777c0de5331.gif @ engineerdude for reviving a 6 month old thread in the first place!