The efficiency of the speaker and how the amp reacts to the load. It's as simple as the amp asking the speaker to move, or telling it to move. We talk about watts as if they are all the same. !00 volts at 1 amp is 100 watts, but 25 volts at 4 amps is also 100 watts. P = I X E. The more amperage an amp can put out the more control it has over a driver, specially large drivers with heavy cones.
Why do speakers improve with more powerful amps?
So, if I have a solid state amp that more than adequately powers a speaker, why do people recommend a larger more powerful amplifier to improve things?
Why do more powerful amplifiers impact speaker sound quality in a favorable way? Is it because more power is reaching the speakers? Mid and Tweeter drivers I was told receive a reduced signal versus bass drivers which receive relatively more power via crossovers. All for the purpose of balancing a signal going to the various drivers.