im kinda new to this stuff and i was wondering that if a speakers stated impedance is 4 ohms can u run it at 2 ohms if your amp is capable of this? ive searched through the forums and couldnt really find a clear answer to this. im trying to piece together a system thats not to expensive that i could get for my graduation present.
http://www.sonicelectronix.com/item_...+ZXi+8006.html
http://www.sonicelectronix.com/item_...cs+BX10D4.html
http://www.sonicelectronix.com/item_...+ZXi+5.2C.html
http://www.sonicelectronix.com/item_...s+ZXi+683.html

http://www.sonicelectronix.com/item_...+SALE-+--.html this is the dvd player i like since its a resonable price and its got preamp outputs for 5.1 surround sound that i could add another amp for once i find out how to mount a center channel.

these are the other amp choices:

http://www.sonicelectronix.com/item_...ik+V204XT.html
http://www.sonicelectronix.com/item_...g+ZX-8200.html

or this subhttp://www.sonicelectronix.com/item_2719_Volfenhag+ZX-4710DVX.html sorry for the book but im completly lost on whats good to use and whats not and im lookin for decent prices, ive been readin on here for awhile now and you all have awsome stuff but the prices are a bit higher than what im lookin for, any help or ideas what be great. and im not looking for the best sound quality there is, just much better than stock, thanks,
Scott

 

Ohms only matter at the amp side. Once you figure out what speakers you want you can figure out if your amp will handle the ohms you give it.

A great website for figuring all this out is basic car audio electronics.

http://www.bcae1.com/spkrmlti.htm

I probably would go with your HiFonics choices but none of those secondary amps. If you can, budget a bit higher for the headunit. You might cheak out onlinecarstereo.com and get a rebuilt head unit for near %50 off normal price. Then just add on a warranty.

 

Ohms is a measure of resistance, you cannot chance a speakers resistance, an amp will see a 4 ohm load with a 4 ohm speaker. Ohms dont really matter other than matching an amp to a speaker. 1 watt at 1 Ohms = 1 watt @ 8 Ohms, an amplifier just has to work harder to produce a watt at a higher resistance. this is why 1000w 1ohm subs are more popular than 1000 8Ohm subs for instance, an amp capable of 1000W @ 8 Ohms is very big, heavy, and expensive.

 

so those hifonics speakers i picked would only let the amp run in a 4 ohm load? but i could wire the dvc's on the sub to run in a 2 ohm load correct?

 

or would it just benifit me more to find seperate amps, one for the sub and one for the speakers. i just really like the idea of just having to mount and run wires to one and its kinda need something i dont see very often

 

I don't think your grasping how an amplifier works, speakers dont just let amps run ohm loads, the amp is designed to provide a given voltage (depending on input) at a given Ohm load, it just so happens that 5 channel amps has.... well..... 5 channels, 4 for speakers and one for a sub, the sub channel is its own seperate channel so you can have a 2 4 6 8 or 30 ohm Load and not affect the other 4channels. but yes the amp is designed to be stable with down to a 2 ohm load on the 4 fullrange channels and a 2 ohm load on the 5th sub channel.
now since you don't know alot about speakers and impedance I'll clue you in on a secret..... an amplifier will not see a ruler flat 4 ohm load across the frequency range with a 4 ohm speaker. in otherwords YOU'LL BE FINE!

also If you don't need more power than the 5 channel amp provides then theres no sense in runnning multiple amps

 

sorry if im buggin you with this lol but ive just got a couple more questions, the amp stated power is 110x4 at 2ohms and 55x4 at 4 ohms does this mean that when there are higher loads on the amp it would push 110 watts? i know im askin alot of questions so if theres a site that i could go to that i could just read all this that would be great. thanks for the help,
Scott

 

the amp with less resistance will pull more power from the battery with a lower ohm load. it'll also supply a higher voltage (more watts) since there is less resistance load. the trade off is this generates more heat. it makes the amp work harder but its like how you overclock a computer processor, your limited by how well the heatsink can dissapate the heat generated by the mosfets. if its 2 ohm stable then its basically rated to be able to dissapate the heat with a 2 Ohm load and run stable fo hours. you can actually run a lower load for a few minutes on a cold amp, but the heat will build up fast and eventually the amps thermal protection circuit should shut itself down

 

Actually a speaker is reactive, it has inductance, capacitance, and resistance. Together this makes the impedance. Impedance can change resistance cannot. So the amp does change the speaker impedance based on what frequency it sends it.

So, for example, at a drivers resonant frequency the driver will..well.. resonate, therefore less energy is needed to make it move at it's resonance, therefore at this point the resistance will rise... By quite a bit.

In other words an 8 ohm driver will not remain at 8 ohms thru it's passband, it will vary depending on the mechanical and electrical characteristics of the driver in motion. In a static state it will have DC resistance which is the nominal figure.

This is also know as the impedance response curve with impedance on the y axis and frequency on the x axis.

Like this:

http://www.soundstagemagazine.com/me.../impedance.gif

It's just that technically, as the graph shows, speakers are NOMINALLY x ohms, but change over frequencies sent it by the amps because they are 'reactive.'

And the simple answer to your dual voice coil question, yes, if you hook positive to positive and negative to negative (placing in parallel) your dual voice coil sub, it will half the ohms from 4 to 2, meaning your amp should be capable of stablely providing power to a 2 ohm load as Styx said, at usually twice the amount at 4 ohms, if you hook it up this way. Optionally, if you have the extra channels on your amp you can hook one channel up to one voice coil at 4 ohms and another to the other voice coil at 4 ohms.


BSEEAugs

 

that pretty much explains it