okay, here is the situation: I have two identical amps that each put out 220 watts at 8 ohms. I have a DVC speaker that has a recommended power of 400 watts total (200 per voic coil), and 800 max. So I am wanting to find a way to wire up both of these amps to the same speaker. The only problem is that the speaker has 4 ohms per voice coil. So I know that it is a really bad idea to just plug one amp into each voice coil, and I was wondering if there is a good way to bridge the amps in some way or what. since the speaker is a DVC, I can wire that up for 2, 4, or 8 ohms. and I didn't know if bridging the amps in some strange way would work (I don't even know if there is another way to bridge an amp, other than in parallel). If not, would it be okay to plug one amp into each voice coil, as long as I kept a good fan running on the amps, or is that still a really bad Idea? any ideas would help. if there isn't any way that I can make these amps work, its not too big of a deal. But I really would like to make it work.

 

well, i don't understand what sub you have, because a dvc sub can only be wired to have two different impedances. a dual 4 ohm sub can be wired to 2 or 8 ohms, a dual 2 ohm sub can be wired to 1 or 4 ohms. most dvc subs are dual 4 ohm. if it is a dual 2 ohm, wire it to 4 ohms, and just run it off of one of those amps bridged, that should put you near or over 400 watts into 4 ohms, otherwise spliting the amps how you described would overpower the speaker twofold. i suggest you get two 4 ohm subs, and run one off of each amp. and you should check and see :
1- if the amp is 4 ohm stable in mono
2- the rated rms power output at 4 ohms mono

 

What do you mean when you say the amps are 220 watts into 8 ohms? What brand are they? I don't know of any current car audio amps that are rated into 8 ohms. I'm guessing that whatever these amps are, they will not be suitable for using with subs.

 

Gotta agree with the masses here. There really isn't enough info provided for us to accurately advise you.

However, speaking from a general standpoint and taking alot of variances out of the picture it is possible to bi-amp a DVC sub. You just will have to match amps, impedance loads, then use test equipment to match the gains so that both outputs are equal and in phase with each other.

In short, it is possible with the right equipment and configuration.

 

okay, sorry I was unclear at first.

my sub is a DVC 4 ohm. when I said I could wire it at 4 ohms, i was reffering to just using each voice coil for one amp. (it is a rockford fosgate punch HE2)

my amps are not car amps, btw. (sry I forgot to specify that) what the deal is is that I am trying to hook up my sub in a house. I have two 8 ohm amps (they are actualy recievers, but I will only be using the amps in them) putting out 220 watts a peice. they are JVC RX-302 recievers. I know it sounds weird. I have done this b4 only I was using two car subs w/ one amp. so I just wired them up in series and it worked fine. this time, I have one sub, and two amps. As far as I am aware, the amps are not 4 ohm stable. so thats the deal.
Also, If I were to run those amps at 4 ohms, would keeping them super-cool be suficiant to keep them from serious damage, or is that still pushing the envelope?

thanx a lot guys.

 

The problems you will run into are:

1) each voice coil of your sub is below the rated impedance of your amp (reciever)... VERY BAD IDEA
2) with 2 RECIEVERS... you run the risk of 2 VERY different signals going to each voice coil of the speaker. Say for example, you've got 2 volume controls.. 1 reciever turned up LOUD and the other turned down... not good for the sub. If someone were to switch 1 reciever to CD input and the other reciever to FM Radio input... you would LITERALLY have 2 totally different signals to each voice coil of the sub.. another bad thing for the sub. These differences can be overcome by using the same signal unit (head unit) and having the same signal to 2 different amps (simply match gains on the amps)... but your situation would be very difficult to overcome with 2 volume controls and various inputs to each reciever (CD, TAPE, STEREO, AUX)

Just basing my thoughts on the idea that you're using 2 home stereo recievers with built in amps to power a single sub.

 

very good point. I could work around that to an extent. but it would be a very big hassle, it wouldn't be practicle at all (I would have to do things like turn off the speaker outs before changing the volume, etc.) So that problem alone is enough to tell me that I really shouldnt try this, even if ohmage wasnt a problem. so I guess i'll ditch that plan. (it was a good thought, though. I thought it was anyway. maybe one day all this brainstorming of mine will come up with something that works!)

Thanx a lot guys for your help. I guess all I really needed was someone to convince me that I am stupid. he he. so I guess that's all I needed. Thanx again!

 

No Problem.. glad to help.

 

Well don't go running out all crazy in the streets now. You can actually get full use of one of the amp/receivers to drive the DVC. If provided the sub has 2-4 ohm voice coils you will be fine to run one amp to it in stereo mode. However, you would want to filter out all high pass information above 120hz. 95% of all music recorded today and in the past is recorded in mono below about 120-150hz anyway so essentially left and right channels would be working in unison. As far as your impedance problem 4 ohm versus 8 ohm this should really not pose to heavy a problem for most quality home amps. The primary reason why most home amps have an 8 ohm rating and not a 4 ohm is due to the fact that the industry has used 8 ohm speakers for home application due to amplifiers giving much cleaner playback in 8 ohm mode. Distortion in a home setup is much much easier to detect than that of a car audio system. If you recall many amps/receivers come with A & B speaker select switches that allow you to run a single speaker or both A & B simultaneously.

Anyway I am rambling. But the jist of it is this you can more than likely run your home amp without problem into a 4 ohm stereo configuration. Besides just like every amp on the market, both home and car, there are protection circuits built in to keep you from killing it and it will let you know quickly if it doesn't want to play by your rules.

 

Another big factor in home audio using 8 ohm speakers would also be the availability of a higher voltage source. Where current is the major power force in the car audio world... voltage is plentiful and amperage is not. A typical home wall outlet typically will have a 20 amp or less breaker... so, to increase power, increase the voltage. This is done with a higher impedance load such as 8 ohms versus 4, 2, or even DVC 2 (1 ohm) ohm speakers in car audio.

Notice how with a car audio amp.. you drop the load impedance your power goes up? This is just ohm's law at work... lower the resistance with the same voltage and your current goes up thus increasing the power.

(I'm sure I'm not saying anything many of you don't already know)

 

TEK has another strong point there, for the most part AC voltage and DC voltage play by the close to the same rules but the higher voltages in the home realm (120 VAC) vs. that of car (12.75-14.25 VDC) allow for larger power outputs with lower amperages due to the increased voltage. So the typical 1 amp/10 watts rule of thumb is not applicable to the home audio amps. It would be closer to 1 amp/100 watts due to the increased voltage. Both figures account for some loss.

 

okay, so I want to double check and make sure I understand what you guys are saying.

as I hear what you are saying, you think it would work to use just one amp, and hook up one channel into each voice coil, (but just make sure both channels are exatly the same.) and then it I should be getting a little more than 220 watts out of the amp, since it has a lower resistance. and all I need to do is keep a close eye on the amp and make sure I am not pushing it too hard. then everything should work fine.

do I understand you correctly?


thanx

 

NO

You need to wire BOTH voice coils into ONE channel of the amp in order to present the amp with an 8 ohm load. You should wire the 2 voice coils in SERIES.. dual 4 ohm voice coils in series 4 + 4 = 8 ohm total. This will power your sub with whatever power 1 channel of the amp outputs at 8 ohms. I would highly discourage you from presenting the amp with a load that is BELOW its rated 8 ohm minimum impedance... you run a very serious risk of damaging the amp regardless of "how hard you work it".

 

Well another question I have for you before I say it would be ok to run it into 4 ohm load is what kind of amp do you have? Let me know and I can check the manufacturer recommendation on it to see if it stable at 4 ohm. I will need make and model number of the amp.

 

oh, okay. IC. ill try that, then. thanx a lot.