Quote:
Originally Posted by Koen
Another way to avoid high current, especially for subwoofers, is using an 8 ohm speaker. I know that in theory can have more watts from a 4 ohm speaker, but taking in account the power losses, that shouldn't be much of a worry. And speaker efficiency is just as important: a speaker at 92dB only needs half the power of a 89db chassis to reach the same soundlevel.
K.
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Hey,
Just going to jump in here a bit as I have dabbled in high power ICE systems in the past. If your interested in seeing it check here :
MainPage Then click on the S16 Page.
I wouldn't be entierly convinced your idea of using an 8ohm subb woofer will necassarily help in reducing the current draw down the power line. While good in theory the amp is still going to pull it's required amps regardless of what is connected at the end of it, only then when power is at the amp will the amp itself then run cooler through the 8ohm subb loading it up a bit more and not allwoing the power to flow so freely.
Just thinking about this somemore (it's been a while since I've had to think of this) an 8ohm load is going to add more resistance to the amp, hence power will backup. A 4ohm load allows the power ffrom the amp to flow more freely.
Lets not forget an 8ohm subb connected to the bridged output of an amp will be seen as a 4ohm load at the amp anyway, load ~ divided by 2 (as it's on the bridged output) = 4 ohms at the amp.
A 4ohm subb will present a 2ohm load at the amp, current will flow more freely and the RMS power goes up.
In the 306 I had above I was using 2x 8ohm 15" JL Audio subbs, I went 8ohm as the original Calibre amp was not capable of running 2 ohms bridged mono. As you can see though I still ended up going to a Phoenix Gold ZX500 after blowing 3 Calibres up!
I was also running 1/0 gauge power cable & a 1 farad capacitor to smooth the power delivery.
We need to bear in mind that electricity does not flow in the wires but along the out side of it, hence good quality audio power cable has multiple thin strands of wire which increases the surface area of the wire compared to it's size.
Even though the car cabling will be of good quailty it wont have a high strand count and as amps are pulled it will not be as capable of delivering them as well as a multi strand cable.
For safety I'd say fit an 8 gauge power cable minimum from a fused connection under the bonnet to the boot. It's a pain but will be safest and should you have a fire your insurance company cannot say it was the faulty ICE install.
Pulling major amps down a thin wire will make it heat up and it's near plastics & carpet.
Ian