Re: How many watts is my sub getting
This isn't really accurate - the voltage output of the amp sags relative to its theoretical output when connected to a real load.
Ohm's law is always true - what is constant is the equation P = IV, not necessarily the absolute value of any of the components. When an amp reaches its current supply limit, the voltage starts sagging, which is the symptom felt when there's no more juice.
In other words, it's not possible to vary the current supplied to a static load separately from the voltage - if the voltage goes up, so does the current. If the load impedance drops, the current demand increases, which will pull down the supply voltage to the equlibrium of what that supply can deliver. There are various feedback circuits that can be used to increase the supply voltage to maintain a constant output current, but these only work within the capabilites of the supply.
