not to sound lame but i have no idea what 2 ohm 4 ohm and all that sort of business is. see it written all the time as ie.

Specifications:
Power / channel @ 4ohm 14.4V: 50WRMS x 4
Power / channel @ 2ohm 14.4V: 80WRMS x 4
Power / bridged @ 4ohm 14.4V: 160WRMS x 2
from the jaycar site.

i understand bridged just not the whole ohm thing. sorry if this is lame but would just like to know what it's all about.

The ohm is the unit of electrical resistance. Current will flow better at lower resistance, putting out a higher power rating.

P = V.I

Where P = power (W)
V = Volts (V)
I = Current (A)

with a constant voltage, a higher current will increase the power ouput, giving the amp more quality.

thus the need for capacitors and the rest to provide a constant clear voltage to the amp i'm guessing? how do you achieve 1, 2 and 4 ohm loads?

Ohms is a measure of resistance to current flow.
The higher the ohms, the more resistance to the current (flow of electrons).

When you connect a speaker to an amplifier, the amp sees the speaker as a load... or a object that resists the flow of electrons that the amp tries to push through it. The lower the resistance the easier it is for the amp to push current through it.

So at 2ohms most amps (if they are 2 ohm stable) can produce more power than at 8ohms.

Make sense?

Cheers
Pete

I personaly wouldn't worry about capacitors, unless you are running like 3 or more amps, with lots of audio gear, with large power ratings. But yeah, thats the principle, they store voltage and releases it at a constant rate.

Acheiving the different resistance's would be an issue of how you would wire it up, at which point you would consult the manual for your amplifier.

Failing that, wait for Tim to come and post on here... he knows everything! :P

thus the need for capacitors and the rest to provide a constant clear voltage to the amp i'm guessing? how do you achieve 1, 2 and 4 ohm loads?

No capacitors are only a bandaid fix for the real problem. The real problem is quite often the size cable you are using and your battery. Get a bigger cable and the amp doesnt have to work as hard to 'suck' current from the battery to run. Think of you trying to suck a thickshake through a small straw or a big straw.

Most normal car speakers are 4ohm. Subs however differ. Single voice coil subs as a rule of thumb are 4ohm. Dual voice coil subs can be wired either for 8ohm (voice coils in series) or 2ohm (voice coils in parallel).

Cheers
Pete

cheers guys. got the picture now. thanks heaps for the quick replies. sorry for seeming so daft bu hey.....dont ask and you dont know huh?

gonna head down and get one of those jaycar 4 channels to run the other bits and pieces in my car in the next week or so. heard nothing but good things about them so far so i thought i;d give it a crack.

heres a website on basic car audio electronics :D

Basic Car audio electronics link (http://www.bcae1.com/)

Theyre all wrong mate. This is the right answer to your question.
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When everthing is going right when your with the missus, she should be saying.......ohm...ohm..lol lol lol :D

Always thought it was what the Buddhist monks said when they were meditating.. :think:

Whilst ohm is the unit for resistance for DC signals, it is also the unit for "impedance" for AC signals. Impedance is the result of resistance and the affect of the current and voltage becoming out of phase when passing through a "component". A component may be a capacitor, inductor, resistor or a combination of any of these.

This is why you won't be able to measure 4 ohms across the terminals of a 4 ohm speaker, the ohm value contains the resistive and inductive affects of the speaker. Follow the guidance of your installation manual for how to connect the speakers together.

PS. Ohm is also the inverse of Mho, which is the old unit for conductance (no kidding).

Ken

http://en.wikipedia.org/wiki/Ohm_(unit)

Just because no-one else has done it. Magnatised was right with his P=V*I. But it may make it more obvious if I say V = I*R and therefore P=I^2*R. Because current (I) is a good thing with speakers/subs/music things, a decrement in resistance (R) is a good thing (power is constant, therefore R goes down and I goes up). The thing is, if the current is too high, you can destroy the wires, or the speaker/etc. or even both. Then again resistance stuffs up a signal. Make sure the wire you use can handle the amps (i.e. current) or upgrade the speakers/etc. so that the resistance is higher.

heres a website on basic car audio electronics :D

Basic Car audio electronics link (http://www.bcae1.com/)


cheers mate. appreciate that.

Sorry...had to post...
On the Capacitor note...As i've said before...

"The reason your headlights dim is because you are drawing enough total current from the alternator that it can't supply the alternator’s output regulator with a high enough voltage to give you your normal charging ~13.8 volts.

When the car is running most of the current is supplied by the alternator, this can be drawn by your lights, the battery charging, etc. The higher the current drawn by these devices the less headroom you have for your stereo. To add to the load, voltage drop in undersized cables also wastes power (results in heating up cables/fire risk).

When enough current is drawn to drop the regulated alternator output voltage to the normal battery charging voltage then the battery also starts to supply current instead of being charged/floated.

If the battery is in good condition and has a fairly low ESR (ie. high CCA capacity or ability to supply a lot of current quickly in lay terms) it should be able to provide more than enough current instantaneously to power all of your equipment with the engine off. How long for is another question...

A capacitor right next to your amp will provide a buffer, pretty much; if the voltage at the cap becomes lower than the voltage in the cap, the cap will start to supply current as well.

When a loud bass note hits, more current is drawn, more voltage losses in cables and alternator voltage output drops. With a capacitor there, it supplies the amp with current minimising the voltage drop in the line. The amount of time it can supply this current for is only very short so it may work for one off hits but the extra current drawn by the cap when it charges back up can cause even more issues if cabling is insufficient.

No matter how good your cabling is you will always get voltage drop when you are drawing current. Amps have caps on their power inputs (internally) so that these transients don't usually affect the quality of the amps output.

If these caps are proving insufficient; look at your wiring for losses, check your alternator function/capacity and check your battery.”


On the amp output note:
The amplifier output power will vary with a change to the impedance of the load. This is because the amplifier is a ‘voltage amplifier’, ie. Puts out a certain voltage for a certain voltage input signal. The reason it is not proportional as the formulas mentioned would suggest is that the amplifier will have an internal resistance. Think of it as kind of a resistor inside the amp in series with the output. This resistance will consume a greater proportion of the power output as the load impedance gets closer to the value of the internal resistance. This means less power to the speaker… The amplifier may also become ‘unstable’ when this value is approached, meaning that it can’t reproduce the input waveform properly, this is why the manufacturers specify a minimum sable load impedance.


On a side note: Impedance is the sum of both the resistive and reactive components of a circuit.


Cummins.

don't you just love the physics lessons :P been a few years

Power (watts) = Voltage X Amps (current)
or Voltage = power / Amps
or Amps = power / Voltage

wait till we start talking about filter capacitors and High, Low pass filters lol