Ok, I'm rusty on my ohms law and need some imput. My cousin wants a stereo that you can here three blocks away (I'm buying stock in a hearing aid company :D)...

Anyway I was thinking about 4 2ohm subs. I'm going to wire them in a series parallel circuit so I have a 2 ohm load at the amp (mono). Two speakers will be in series for 4ohms. They'll be in parallel with two other speakers in series at 4ohms for a total impedance of 2 ohms. Correct?

My question is about the power. Each speaker has a max RMS power of 400W. The max I could feed it is 1600W, correct?

Also refresh my memory, Voltage is constant in a parallel circuit and current is constant in a series circuit, right?

Thanks,

David

If it was me I would rather try to get parallel connections between the speakers (which would mean a higher resistance speaker to start with). Years ago I always seemed to hear a difference between wiring subs in series compared to parallel as one seemed to move slightly out of phase with the other (the signal has to go through one, then to the next one). Now whether this was something I was imagining or something else, I don't know but today the manufacturer's sell different ohm speakers to where most of the time it allows for parallel wiring.
Now if a sub has dual voice coils, I have series wired those (dual 4 ohm voice coil sub wired in series will give 8 ohms) and not had problems or sound differences as the windings of the voice coils are stacked on top of each other inside the one speaker.
Also watch your impedance (resistance) when wiring in mono. Some stereo amplifiers can be wired up in a mono load but the amplifier "sees" half the load. A 4 ohm sub wired in mono to a stereo style amplifier will have each half of the amp seeing a 2 ohm load. I see this as a problem with most customer's that think they can just wire up a second 4 ohm sub later only to find out the amplifier goes into protection mode or runs extremely hot and burns up and the amplifier was "seeing" a 1 ohm per channel load. Some newer style mono only amps if you wire up a 4 ohm speaker to it the amp sees 4 ohms.
Another thing to watch out for is how low you go with the resistance. Any amplifier manufacturer should be able to tell you what the lowest resistance is you can wire to that particular amplifier. If you go lower it may put out more power but it will also draw more juice off of the electrical system and create more heat. Speakers too will also exhibit a resistance different than what you measure with a DC ohm meter. Some speakers may measure 4 ohms with a meter but when the signal goes through them and the voice coils heat up the reistance will change or other factors come into play such as the enclosure design.
When you go to build the enclosure, run the larger size that the manufacturer suggests and also port the enclosure for some added output at the port tuning frequency.
High powered audio systems in cars are like a high output engine. You have to look at the whole picture. If you build a high horsepower motor you have to think ahead and maybe get the transmission beefed up as well as the rearend and then maybe too have to run a bigger fuel system. An audio system uses amplifiers that if hooked up to the wrong speakers can cause problems and also if not supplied with enough electrical juice can also cause problems.

Jim

You are correct in what you've written.

I too just don't see series drivers as a good idea. Any unequalities in the two drivers will lead to unequal power sharing. If you do it then connect the middle series connections together too. In other words, put 2 in parallel and then connect them to the other set also connected in parallel. I hope that makes sense.

I also just don't see you needing any more than 2 good subs. Some of them are massive and have huge power handling capabilities.

Peter