I need to know everything about car subwoofers and amps.?

Question

If i get two 800(peak) watt subs with rms of 400 which wattage will i get? How many watts should my amp be? What brand of amp or sub do you reccomend? I'm buying 2 10" kicker 800 watt subs will this be reliable? What are ohms. Please don't be very technical break down for me.

Answer 1

First, never use PEAK for watts. Always use watts RMS (root mean square) as this is a more accurate means of measurement.

Ohm's is a measurement of resistance. Think of kinking a garden hose, the more you kink, the more resistance.

In electronics, the less resistance across a power source, the more it's a dead short. So it's much better to run an amp at a higher resistance than a lower one, contrary to popular belief.

You do get more power from lower ohms, but at a price...

This will:

1) cause the amp to run hotter
2) increase the THD (total harmonic distortion)
3) reduce the life of the amp because of excessive heat

I would recommend getting two 400 watt RMS DVC (dual voice coil) subs and a mono 800 watt RMS @ 4 ohm amp if you want to stay in this wattage range.

As watts are always added when subs are wired together, the amp needs to be twice the watts RMS.

The resulting ohms depends on the wiring method used.

For series http://i81.photobucket.com/albums/j230/sparky3489/SERIES.jpg the ohms are just added together.

For parallel http://i81.photobucket.com/albums/j230/sparky3489/PARALLEL.jpg there is a formula and it's this.

Where Z = the total impedance (ohms) and sub# is each sub (or each coil in a multi-coiled sub):

Z = 1 / (1/sub1 + 1/sub2 + 1/sub3 + ....) for as many you have

The quick and dirty is IF both subs are equal in ohms AND wired in parallel, the ohms will be cut in half.

You can mix these two methods of calculations for different configurations, as so....

For DVC subs, the wiring is different. I said earlier to get a mono 800 watt RMS amp @ 4 ohm because two 4 ohm DVC subs wired like this http://i81.photobucket.com/albums/j230/sparky3489/PARALLEL-SERIES.jpg results in a 4 ohm load. This will sound so much better, the amp will run cooler and last longer than loading an amp to 2 ohms with an 800 watt output.

You can wire as many subs to a channel of an amp as you want AS LONG AS you don't fall below the recommended impedance load of the amp per channel.

Brand of amp is dependant on preference. Just be sure the amp is CEA-2006 compliant.

For subs, the higher the dB sensitivity (>90dB) and lower the Hz (20 - ???Hz) the better.

The enclosure the subs go in is just as important as anything. The wrong enclosure will give less than desireable results. The manufacturer of the subs should have recommendations of size/type of enclosure to use.

The power and ground wire size depends on the power of the amp. For an 800 watt RMS system 2 AWG would be recommended. A fuse will need to be place no more than 18" from the battery as you will need to make a direct connection to the battery for power. The fuse should equal the sum of the fuse ratings on the amp. The ground wire should be securley fastened to the chassis of the car as close to the amp as possible. Scraping the paint away where the ground connection is made will give good results. Use lock washers to secure it. Just be careful when drilling that you don't hit the fuel tank or other important systems.

If you have an aftermarket stereo, you'll need to run well sheilded RCA cables no less than 12" from the power wire to reduce inducted noise.

In it's a stock stereo, you can either get an amp with "high level" inputs and tap off the rear speaker wires to provide signal or get a "line level converter" and do the same thing.

The gain on the amp MUST match the RMS volts coming from the stereos output for best sound quality. The LPF (low pass filter) should also be used to prevent high frequencies from reaching the subs as this will cause them to overheat. The LPF should be set just a little less than the the highest Hz rating of the sub.

You can E-mail me if you have questions [e-mail]

See my site for more info http://spkrbox1.spaces.live.com

Some other places to visit:

http://www.bcae1.com
http://www.the12volt.com
http://www.installdr.com

Answer 2

Go here:

http://www.caraudiohelp.com/newsletter/index.htm

They have a bunch of very informative articles.