Look for this when buying an amp... http://www.crutchfield.com/S-OSAZiuYKz12/popups/cacomp.html
CEA-2006 Compliant
On May 28, 2003, the Consumer Electronics Association published standard CEA-2006, "Testing & Measurement Methods for Mobile Audio Amplifiers." This "voluntary" standard advocates a uniform method for determining an amplifier's RMS power and signal-to-noise ratio. Using 14.4 volts, RMS watts are measured into a 4-ohm impedance load at 1 percent Total Harmonic Distortion (THD) plus noise, at a frequency range (for general purpose amplifiers) of 20 Hz to 20,000 Hz. Signal-to-Noise ratio is measured in weighted absolute decibels (dBA) at a reference of 1 watt into 4 ohms. This applies to both external amplifiers and the amplifiers within in-dash receivers
If an amp doesn't have this rating, it's doesn't produce the watts it says it does.
http://spkrbox1.spaces.msn.com/ for real "sound" advice.
Your system won't mean squat without a well designed box to put your subs in. Some manufacturers have recommendations as to dimensions of various types of boxes. It is best to find someone who builds boxes if you go with something other than a sealed box.
You should always match up RMS (Root Mean Square) watts of Subs and amp per channel as well as impedance's(resistances). When a sub has rating of 600 Watts MAX it really has an RMS rating of about 200 Watts RMS. RMS is the nominal wattage your most likely going to get out of it. Remember, a 200 Watts RMS amplifier has more power output than a 200 Watt MAX.
If your amp is rated at 4Ω don't subject it to 2Ω, it will fry.
Here is the formula for subs in parallel:
Z = 1 / (1/sub1 + 1/sub2 + 1/sub3 + ....)
For series, just add them up (sub1 + sub2 + ...).
You can mix and match these equations to get the right impedance required by your amp.
Example 1: Amp is 2 channel and rated at 4Ω, 4 subs @ 4Ω each. If I connect two in parallel and the other two in parallel and connect the two pairs in series, I would have a total impedance(resistance) of 4Ω. So to the amp, it's just one sub.
Example 2: Amp is rated 1Ω mono, 2 subs @ 4Ω each dual voice coil. If I connect two voice coils in parallel and the other two voice coils in series and connect the two subs in parallel, I would have a total impedance of 1.6Ω. Which would be perfect for a 1Ω stable mono amp.
You should use a capacitor as well.
Recommend for every 500 watts MAX you use a .5 Farad cap
Example: 1000 watts MAX - 1 Farad cap
You will also need what's called a "line level converter" if your stock head unit doesn't have RCA outputs or your amp doesn't have high-level inputs.
Try http://www.soundomain.com/shop you can find some really good deals, and this site is manufacturer certified. VERY IMPORTANT WHEN SHOPPING ON-LINE!!!
If you like I can send you some plans for reference. My plans are for a 4-th order band-pass bass box (A.K.A. bass-reflex) that holds two 12's.
Also included are java calculators you can use to figure parallel and series values given Ω values, tips on box building and types, calculating port diameter and length(if used), calculating box dimensions for types of boxes (sealed, wedge, cylindrical, etc.), materials needed and even how to make a jig for cutting perfect holes for your subs.
Just e-mail me sparky3489@yahoo.com
My system
Blaupunkt TSw1200 subs with a Sony Xplōd XM2200GTX.
My amp is 1200 watts (200 Watts RMS X 2), subs are 600 watts (200 Watts RMS) each, cap is 1.5 Farad w/digital readout
SPL is about 112 db each sub
Total cost(so far) = $410
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To the other people ranting about my answers.
Some people have made pot-shots at my post because my answers are "one size fits all" as one person put it. I have gotten at least 25 best answers (and growing) with e-mails requesting more information from this same post since I posted it.
I'm just trying to be as informative as I can be. There might be something the poster didn't think of, forgot about or doesn't know.
These peolpe may not like my style of response, but then, no one asked them.
2006-07-05 02:11:24
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answer #1
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answered by Anonymous
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