You didn't mention if that 1800W is Peak or RMS - I'll assume it's RMS.
(In case you don't know the difference: RMS is basically the power level it can handle all the time. Peak is the power level it can handle for a short period of time before damage potentially occurs. Usually, Peak is double the RMS rating.)
Many installers are comfortable recommending a 1 to 1 ratio. So, your 1800W sub would need an 1800W amp.
I don't feel that gives enough of a safety margin. I prefer a 1 to 1.3 ratio. In which case your 1800W sub would need a 2400W amp.
Yes, a 1200 watt amp can power a 300 watt box. The wattage of the amp refers to its maximum power output, so it can deliver up to 1200 watts if needed. As long as the amp is set up properly and not pushed to its maximum capacity, it can safely power a 300 watt box.
no you must go lower or the same
sure. Will it be loud? No. Its just not enough power to drive that sub.
4 gauge
A #8 conductor is rated at 40 amps. Wattage is the product of amps x volts. As you can see the voltage is needed in this question to answer it. In the electrical trade I have never come across the terminology watt amp. Volt amp, yes.
Volt-amp is a unit of apparent power, which is the combination of voltage and current in an electrical circuit. Watt, on the other hand, is a unit of real power, which is the actual power consumed by a device. The relationship between volt-amp and watt is that watt is the product of volt-amp and power factor, which represents the efficiency of the electrical system. In simple terms, watt is the actual power used by a device, while volt-amp is the total power flowing through the circuit.
a watt is power, or 1 joules sec= 1 watt an amp is 6.242 × 1018 electrons passing a given point each second,
Yes, are we talking rms or max? If its rms you will have no problem. well the amp is a 1500 watt max but 350wx1 rms in 4 ohm
It's actually a good idea to have a speaker that can handle higher wattage than the amp can produce.
A minimum of 15-amp breaker is "needed", but a 20-amp is often required by electrical code for that situation.
1200 Watt wiring is more than enough for an 800 Watt amp. The rating of the sub doesn't make any difference to the cables. If you want to use the sub to its rated power you should get a bigger amp. If the amp can only give out 800 Watts and the sub can take 1100 Watts then you can put a bigger amp on. It is still going to be loud as with an 800 Watt amp. I have a 300 watt amp with a 1200 Watt sub and people hear me coming.
It depends on the power and impedance rating of the 12-inch speakers. If both speakers are rated for 175 watts and the amp can handle the impedance of the speakers, then the 350 watt amp should be able to power both speakers effectively.