Would you mind explaining the difference between apparent and true power for me? I don't follow.
Well it all comes about because current is a vector. In other words it has a magnitude and direction. Now unless a circuit is purely resistive then voltage and current do not follow each other in an AC circuit. This causes current to go in different directions and can create a phase angle.
Now consider a purely inductive circuit, where the impedance of inductance far exceeds the DC resistance of the coil. Now apply an AC signal. There will be current, but it will keep on reversing. Now if you measured the voltage and current at an instant there would be a current. You could multiply this by the voltage and have a power, in VA. This would be apparent power, because actually there would be no power as the current would be going up and down a straight line, so the phase angle would be zero. The cosine of zero is zero. Multiply the current by 0 and you have 0. So there is no actual power. However the current flow is real. In fact there is some power consumed by the resistance of the circuit, but lets assume the circuit is cooled close to absolute zero, like the coil of an MRI scanner. If that were the case apparent power would be volts X amps but true power is zero.
Now lets add a resistor in series with the inductor. Now there is power consumed in the resistor, but there is now a phase angle. The apparent power is still VA, but real power is VA X cosine phase angle. The true power will be less than the apparent power, but the instantaneous currents that create the measurement of apparent power still have to be provided by the amp. Now the same things happen in capacitative circuits, but the phase angles are opposite, because current leads voltage.
Now a speaker has inductors resistors and capacitors, so you can see how it gets complicated and hard to predict, especially given the fact that audio signals are complex and the sum of thousands, may be millions of sine waves, to create a complex wave at an instant.
May be this gives you insight as to what a witches brew it really is. Since the outcome at an instant is to all intense and purposes unpredictable, the best defense is adequate power and the ability to provide lots of current.
All things being equal, and given equivalent attention to design I have found beefier amps to produce better sound more often than not.
This is like poor Senator Obama who did not want to have to give a speech on race. However it was one of the finest dissertations ever given by a politician, or any one for that matter on the issue.
I doubt I have been so effective on shedding light on a subject I was hoping to avoid. However the way the member phrased the question, unless I just said no, there was no avoiding it.