Why are car audio set ups offten 4ohms, compared to home audio set ups that are 8?

[ July 14, 2004, 05:50 PM: Message edited by: mister steve ]

 

Because it's not easy to get amplifier output from a 12 volt power source. The lower the impedance of the coils, the more power you get out of your amplifier. (My Thought anyways)

[ July 14, 2004, 06:44 PM: Message edited by: bigmike216 ]

 

my home setup is 4ohm

 

I have wondered the same. My home audio is mostly 8 ohm except for the surround speakers. Maybe has something to do with better sq out of higher impedance drivers?

 

I don't see how you would get better SQ out of higher impedance drivers ...

Anyone care to explain ?

 

more impedance means that the driver is taking more energy from the current flow and using it to make sound.

 

Wouldn't the current be less into 8 ohms ?

According to Ohm's Law ...

Power = Current*Current*Resistance
P/R = I^2
Sqrt(P/R) = I

If P = 100 watts and R = 4 ohms, I = 5 amperes
If P = 100 watts and R = 8 ohms, I = 3.535534 amperes

[ July 14, 2004, 08:02 PM: Message edited by: Jmac ]

 

Where's Dukk when you need him? [img]smile.gif[/img]

 

One big advantage of high impedance is being bale to lower the mass of the voice coil because the current is lower thus making the speaker more efficient. Wattage may stay the same but High Voltage and High Impedance gives you a low Amperage (if compared to the same power mesurement of a low impedance high current setup)

I think it has to do with amplifier circuitry. I think it is easier to pull high amperage from a car 12V source then trying to up the voltage and then powering higher impedance speakers. I know JBL did a video and had some literature on this stuff with their new line of amps.

[ July 14, 2004, 09:44 PM: Message edited by: dbEric ]

 

Higher impedance for home=
Higher damping Factor
Smaller wire for coil because of less current
Cheaper to make high voltage power supply then high curant (120 volt input 15amp)

Lower impedance for car=
Cheaper to make high curant power supply then high voltage (12.5 volt input 5amp to xxxamp)
Cheaper power supply and even no ps
Better efficiency
Bigger wire for coil and speaker