Happy to. Decibels, abbreviated dB, are a measure of relative power. That's all the term means. The power can be acoustic, electrical, or horsepower, though the term is most often used in electronics and acoustics. When I say, "putting 6-8 dB more power into the speakers," I'm referring to the power input to the speakers. 6 dB is approximately four times the input power, so if the Coliseum puts out 300 watts and the Crown 1200 watts, that's an increase of about 6 dB. Going from 200 watts to 1200 watts is an increase of 7.8 dB.
That's on the input side. On the output side, we're dealing with acoustics. As those 1200 watts are pumped into a speaker cabinet that's less than 10% efficient, as yours probably is, that means that 90% of the power is lost in the form of heat. that means that the voice coils are heating up, increasing their resistance, and making them less efficient. As a result, the acoustic output is not a full 6 dB. That's called power compression. Another factor is that the magnetic flux in the voice coil gap is not constant, and, as the voice coil moves out of the center of the gap, there's less flux, and so less efficient conversion of power to sound. How large these effects are varies, depending on the drivers used, but you can see that increasing the input power by 6 dB will never get you a full 6 dB increase in acoustic output. Just can't happen.
Lastly, your understanding of apparent volume to acoustic output is incorrect. While a 3 dB increase is a doubling of power, it is not an apparent doubling of volume. That takes approximately 10 dB.
So those are the reasons I say that going to a much more powerful amp isn't going to get you as much as you might think.
