mdb_foxmx

Alright, so I'm looking around at amps, and I ran into this question...

So, imagine I've got a dvc sub and I wire both coils (4 ohms each) in parallel, making the whole thing have impedance of 2 ohms. Ok, now the sub is rated at 350 watts rms. I look at the 2 channel amp, and each channel can output 80 watts per channel at 4 ohms, but 160 watts at 2 ohms. I see that 160 + 160 = 320, a pretty good match for the sub. But I can't hook up each channel to the voice coils can I? So long as I get each positive cable together and each negative cable together (wouldn't want to cross these...), it seems like there is no huge problem with this configuration. Am I wrong?

Thanks in advance, and forgive my ignorance

eye_see_you

iTrader: (13)

I think you are mis reading your amps abilities saying 160+ 160 I beleive its more likely that your amp performs at 160 watts @ 2 Ohms stable bridged unless it states in the manual that it does that in most cases it does not.

mdb_foxmx

No, I'm pretty sure it means what I said. Each channel puts out 80W so long as each loop incurs only 4-ohms of resistance. However, if you connect two 4-ohm resistances in parallel, you get an equivalent resistance of 2 ohms. The amp says it powers 160W per channel so long as each loop incurs only 2 ohms of resistance.

Now, I could bridge the amp, but in that case, it says it's only 4-ohm stable, and in that case I'm not going to be able to use both coils on the sub...

eye_see_you

iTrader: (13)

how about posting the amp , model and such so I can help out some more

mdb_foxmx

well, there wasn't any particular amp I had in mind. It was just a hypothetical, but I was looking at several amps on crutchfield. Most that I saw were stable down to 4 ohms when bridged.

What I was trying to do was power 4 door speakers and a sub with one amp...lofty aspirations indeed : / In any case, I think it would be smarter to power the four door speakers with a two-channel amp, with each pair in parallel. Then I could just power the sub with a mono amp like this one:
http://www.crutchfield.com/S-bhAMkId...700M&s=0&cc=01

eye_see_you

iTrader: (13)

why not get a 4 channel and do it right or two 2 channels for the front and rear if you want quality then a mono amp for the subs

My current setup
CLarion vrx735vd Headunit
JL Audio 300/4 ( front and rears)
JL Audio 500/1 (subs)
JL components in the front
JL coaxials in the rear

mdb_foxmx

I assume by "do it right" you mean run a seperate channel to each speaker. Problem with that is that, to get a "good" amp that will drive each of the speakers I'm looking at: http://www.crutchfield.com/S-1G1WC1B...DB6500&g=52000
http://www.crutchfield.com/S-1G1WC1B...00&I=107MMC690

I'd need either a) a 4x100W rms amp (at 4 ohms) and a mono amp, or b) 2 2x100W rms amps (at 4 ohms) and a mono amp. The first case gets expensive. Looking around at Crutchfield brings up only a handful of options, most of which are pretty danged expensive. The second case "could" be acheived fairly cheaply, but I don't want to have to mount 3 amps in a civic, which is pretty short on room as it is.

You can still hook up the door speakers in parallel and make the most of your amp's power. The current in each channel varies as V/R, where V is the voltage applied to the channel, and R is the resistance in the channel. Unless the amp has a power limiter, if you lower the resistance by hooking the speakers in parallel (halfing it, in the case of 2 4-ohm speakers), you increase the current (in this case doubling it). So, as long as your amp can handle the lower impedance (most can handle 2 ohms), you're actually getting more bang for your buck with wiring in parallel.

If I wire the door and rear deck speakers in parallel, I can get a single 2-channel amp that outputs 200W per channel at 2 ohms, and each speaker is taken care of (100W to each speaker). The sub will still need an amp, but I will have gotten everything done with two amps, for less money.

But, the whole point of this post was to see if you could somehow use two channels on the same speaker, namely the subwoofer here. If your head unit has two subwoofer outs, and the subwoofer is a DVC sub, why couldn't you just take the signals from the two subwoofer leads (which are identical signals) and plug them into the two channels of a two channel amp, then take each of those outputs and connect them to the subwoofer (which has it's coils in parallel)? It's a little complicated, but I think it might work.

Does anyone know for sure though?

Edit: Check out the picture of the sub wiring I'm talking about here. I had to draw it on my laptop, so bear with me. Keep in mind that the two channels are coming from subwoofer outs (assuming the head unit has two sub outs).
http://s29.photobucket.com/albums/c271/mdbutphy/

DJayG

Hey,
There is an eclipse 5 channel that does 85x4 and 480x1 I work in the industry and that is unheard of power from an amp that only costs $600. It has 4 ga in and it would pound your sub and accomplish the power for your four channel. I could even sell you the amp if you wanted. www.cartunesetc.com
or just communicate through the forum......whatever u want.

eye_see_you

iTrader: (13)

ok I have two amps that are doing the job just fine and even if you want those speakers 100 watts to each is more than enough in fact you probably only want about 65-75 watts per speaker unless your competing. You can however use one amp with capicitors on the fronts and rears to push all of a system its not unheard of but not the best recommendation either.

two amps is the cheapest solution or a large 5 channel as well as stated above. if your going to push polk speakes from my expereince you are goign to need power to them so its goign to be expensive either way you go.

also as for your drawing yes you can feed each channel of a amp to each voice coil but its not recommended if they are not in phase if one fails you can damage your subwoofer. its best to wire the sub and bridge it to the amp

James77

you dont necessarily need to power the speakers with 100 w RMS. They should sound fine with around 50 WRMS. If you are worried about mounting a bunch of different amps look for a 5 channel such as:

http://www.woofersetc.com/index.cfm?...Product_ID=432

As for hooking the sub up the way you want to.. I would be wary about it.
Click on the link below to get different wiring configurations for different subs. Just go down and put in 1 dvc 4 ohm sub.
http://www.the12volt.com/caraudio/wo...igurations.asp

mdb_foxmx

eye_see_you: Thanks for the input. I was trying to get 100W to each, but the more I look, the harder that seems to be to accomplish for a fairly cheap price. I think maybe I'll try and get at least 70W to each or something like that. Should be enough, right? What about for the sub? If the sub says 350W rms, what should I shoot for? Also, that makes sense about the two channels having to be in phase, and as I understand it, unless you look at some higher quality amps, there can be slight deviations in phase from channel to channel. In the end, it's not really a good idea, which is sort of what I figured : /

Thanks guys for all your input.

eye_see_you

iTrader: (13)

for the subs depends on how much you want to give it.. if you get a amp that pushes 400 watts @ 2 ohms stable for instance your amp will not have to work as hard to push the sub because you can turn the amp itself down or you can get a amp that pushes about 300 watts and have plenty unless its a power hungry subwoofer. All depends on your choice of sub and amp combinantion in the end