School me on car audio I'm trying to put together a sub and amp and i'm trying to figure out how to buy the correct 'amp wiring kit'. I've reached out the two favourite audio sponsors here and they've given me their quotes/advise on how it should be done. I figured I should at least learn a thing or two even though I will take my car to one of them. So, the amp has the following specs: 4-ohm Power: 200 watts x 1 2-ohm Power: 300 watts x 1 1-ohm Mono Power: 500 watts x 1 Peak Power: 1000 watts The wire kit has the following specs:
This is all french to me. Can someone explain the following: 1-Peak power vs 4ohm power? Do I not get 1000W? I only have 1 sub 2-What is RMS power and how does that convert to 4ohm, 2ohm, peak power? 3-Gauge I presume is the thickness of wire. Is thicker the better? 4-I was told Oxygen Free is better than Copper Clad Alum. Whats the chemistry behind this? |
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Peak power is the power that may be reached at one point so it does not matter at all. RMS is the continuous power that it will run at. The RMS depends on your subwoofer configuration. Since your amp is 1 ohm stable, you would want a 2+2 ohm dual voice coil subwoofer. Wired in parallel would put you at 1ohms. When subwoofer is wired at 1 ohms, it will be driven at 500 watts. Yes thicker wire would be better, but for 500 watts, a true 8 gauge is good enough. |
I would go straight to OFC 4gauge power wire, it would give you an option to upgrade to a more powerful amp down the road. |
Do do you compare RMS to wattage at 1ohm then? Is 1 ohm the true power of the amp? Wire parallel? 2 + 2 ohm? What? Is there perpendicular wiring? What if its 4 + 4? I'm lost on this point. 4 gauge vs 8 gauge. Lower the number thicker the wire? |
Shameless plug for an amp if you want one http://www.revscene.net/forums/69576...block-amp.html :D:D:D 2 and 1 ohm stable |
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Dual voice coils on subs will give you options to wire the final impedence. Example on a dual 2 ohm voice coil subwoofer you can wire the subs in either series or parallel to give you 1 ohm or 4ohm options. Lower the number the thicker the wire. |
My sub has these following specs: Size: 10in Power Handling (RMS/Peak): 275/550 watts Nominal Impedance: Single 4-ohm or Dual 4-ohm Voice Coil Size: 2 in Frequency Response: 33Hz - 500Hz (Single) 33Hz - 500Hz (Dual) Sensitivity: 86dB Cutout Diameter: 9 1/8 (230.1mm) Mounting Depth: 5.25 in VC Impedance: 4 ohm + 4 ohm Test Impedance: 1.6 ohms Fs: 33 Hz SD: 330.06 sqCM Vas: 39.7 Ltr Cms: 256 µM/N Mms: 98.5 g BL™: 7.44 Qms: 4.85 Qes: 0.566 Qts: 0.51 No: 0.2% Spl: 86 dB Xmax: 9.5 mm Since its only 1 sub, and it says 4+4 ohm, can it still operate at 1ohm? Which means to power this sub 500W sub the amp will put out 500W and the 8 guage wire kit is ok because it can handle upto 700W? Also, series wiring is christmas lights right? Where one powers the other? Oxygen Free vs. CCA - What makes Oxygen free better? |
http://a248.e.akamai.net/pix.crutchf...4-ohm_mono.jpg This is wired in Parallel, the lowest you can wire too is 2ohm. If you wired in series it would be 8ohm. Oxygen Free Copper VS Copper Clad Aluminum. Copper is a better conductor than aluminum which in return will have steadier voltage feeding your amp. If price of wire is a concern you can pick up welding wire at princess auto for dirt cheap. Are you running a ported or sealed enclosure? |
I've used welding cable in the past. Only downside is that it's more of a solid cable than strand, so trying to get it around tight corners is a PITA. That's about the extend of my car audio knowledge. :p |
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Power is derived from the formula P=VI, or voltage times current. At a given voltage, current is derived from Ohm's Law, I=V/R, or voltage divided by resistance. So power can be calculated using P=V^2/R, or voltage squared, divided by resistance. As you can see, as the resistance becomes less, the power across it increases (because you're dividing it by a smaller number). Now in theory, halving the resistance should double the power; however, there are numerous design factors that may limit the REAL increase in real-world situations - current capability (lower resistance means more current draw, which can cause supply voltage to drop, and also generates more heat), power supply design, types of output stages, the desire to stay below a certain distortion level, and others. One important thing to note: these calculations are based on DC resistance, while speakers are a very reactive load, and the ACTUAL resistance (or impedance, properly) they present to the amp will vary depending on the frequency... which is another thing that can affect the real-world output. Quote:
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In parallel, you add the reciprocals of those numbers then take the reciprocal of that, ie. Rt = 1/(1/R1 + 1/R2)... so two 4-ohm coils in parallel would be 1/(1/4 + 1/4) = 1/(1/2) = 2 ohm. Easier way to think of that last step is just to flip the result... so 1/4 + 1/4 = 1/2, and flip it over (2/1). http://www.the12volt.com/12voltimage...m_dvc_2ohm.gif http://www.the12volt.com/12voltimage...m_dvc_8ohm.gif |
BTW, there's a lot of really great info here, arranged in a sort of "tutorial" format that you can work your way through, learning the basics and then building on that as you go: Car Stereo, Mobile Video, Navigation |
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Also, just want to say THANKS! to everyone that's been answering my questions. Hopefully, this thread will help another noob learn as well.. |
So I get the sub to amp wiring now... I think!! How does the power wire for the amp play the factor? I presume thicker wire is better because it has more strands? Also using my example, the 700W wire will be reasonable because the sub/amp max power is 500W. With that in mind, is the constraint usually the sub? Meaning if the Sub had 1000W but amp had 2000W and the wire had 3500W, no matter what the, the most wattage from the sub is 1000W? If the person had two 1000W subs wired in parellel, the sub would be 500? (assuming 4ohm = 1000 , 2ohm = 500 , 1ohm 250 - is this even a possible?)? |
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Speakers don't have "watts." The rating is simply how much power the sub can handle. The amplifier's rating is how much power it can produce, usually advertised with a given input voltage (from your alternator/battery) at a given distortion level. |
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The reason why I ask about your enclosure is the sub specs that you posted is aligned better for a ported box. |
I've guessing this is for the sub won from us on FB. You basically need a 2ohm stable mono amp that pushes around 300RMS. Depending on the amp and it's current draw likely an 8AWG OFC kit will be sufficient. Lower the "GAUGE" wire, the thicker the wire is. Don't confuse AWG (AKA American Wiring Gauge) with GAUGE. AWG is standardized. Most no name companies use thick insulation but the wiring inside is much thinner. So what they'll call "4 gauge wiring" is really more like 8AWG or less. Just remember it takes power to make power. If you have a huge amp and use thin wiring, yes it will work, but not properly. Think like a fire hose vs a garden hose. Which is gonna be able to supply more water (Or current). Like one other member said, I would recommend 4AWG to give you room for expansion down the road. Down the road you may want to add a speaker amp or a bigger sub + sub amp. Price difference is marginal. That way if you do upgrade you don't have to reinstall the power wire again. |
The length of power supply conductor matters. http://a248.e.akamai.net/pix.crutchf...t-o_large.jpeg Perry Babin has a useful explanation here with a couple of handy calculators. |
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