Audio Systems: Amp & Sub Matching, maximum power transfer, watts rms

Question
QUESTION: Hello, I have 6 15'' 4000W DVC Subwoofers. I am not sure whether to use a mono or 2 channel high powered amplifier. I was thinking about using multiple 4000W Mono Block Class A/B Mean Machine Series Amplifier
1000watts @ 4ohms
2000watts @ 2ohms
4000watts @ 1ohms

Please Help,
         Tony B.

ANSWER: Go ahead....  You will get lots of energy out of a system like that.

The biggest problem you have is to budget the power output of the amps you choose against the impedance of the load - which is dependent upon which configuration you use for wiring the speakers.  A DVC wub is probably two 4 ohm coils which when wired in parallel would give you a 2 ohm load (you must check the specs on the sub to learn if the coils are 8 ohm or 4 ohms).

If you then place two subs in parallel you would end up with a 1 ohm load.  Some amps, even though they claim to be able to drive 1 ohm loads, in reality have trouble doing so.

Since you have 6 subs you must decide how many amplifiers and how you are going to connect for maximum power transfer.  There are several ways to do it; just be careful not to place a load on the speaker that is too low for its performance guarantee.

Best wishes.  Hope the neighbors don't complain too bad!!!!

PS: Don't forget that amps like the ones you are talking about may draw lots of power from your car electrical system.  Have you thought about oversize alternator and batteries for the vehicle?



---------- FOLLOW-UP ----------

QUESTION: Thanks for the information. The subs are dual 4ohm coils. I forgot to to ask you about batteries and alts. Would I need to upgrade both battery and alternator. Based on your information I think it would be a simpler hook up if I just use 6 amps and 6 subs one for one. I heard of overpowering a sub to make sure it gets enough power. One sub is 2000 watts rms, so, if I put an amp on it thats 2000 watts exactly after heating of the amp from playing, would the speaker mess up from not getting its recommended power?

Thanks Again,
         Tony B.

Answer
It has nothing to do with the power ratings. It has to do with impedance matching. If a speaker or speakers connected in series or parallel have a resulting impedance lower than the rating of the amplifier it will do damage to the amp.  The impedance can be higher without any harm to the amp but it cannot be lower. For example, let's say an amp has a specification of the lowest impedance load it is rated for is 4 ohms.  If you placed two 4 ohm speakers in parallel on the amp that would be an equivalent impedance of 2 ohms and would be a potential damage to the amplifier.

In the case of an amplifier that can handle a 1 ohm load it means you can parallel 4 each speakers onto its output if they each have a 4 ohm coil.

In the case of dual voice coil speakers you must decide if the coils will be wired in series or parallel.  For example, you can put the coils of one speaker in series for a total impedance of 4 ohms.  Then a second speaker can have its coils in series. Then, put these two speakers in parallel which gives a total impedance of 4 ohms.  Therefore, 2 DVC speakers can be wired up to give the same impedance as one voice coil.  And so on.  

Finally, the maximum power transfer from amp to speaker is when the impedance of the load is exactly matched to the output specification of the amp.  If the amp is rated for 2 ohm loads, for example, it will deliver its maximum power to the speakers when they are wired for 2 ohms impedance. If the impedance goes up in value the amount of deliverable power goes down.  That is why your amp that you talked about in the beginning had different power output specs with different loads.

Hope this makes sense to you.