Actually, Gary, I was mistaken. The 4B SST does not double power as speaker impedance is halved. Caught me by surprise because I was certain the 4B SST doubled power.
When used with speakers that have a significant impedance curve, i.e. low impedance in the bass regions relative to higher impedances in the treble regions, the result is less volume produced in the bass frequencies relative to the high frequencies. What one hears, then, is a "tipped up" or "bright" sound because the highs are louder than the bass.
However, this effect can be ameliorated by using a speaker with a flat impedance curve.
When used with speakers that have a significant impedance curve, i.e. low impedance in the bass regions relative to higher impedances in the treble regions, the result is less volume produced in the bass frequencies relative to the high frequencies. What one hears, then, is a "tipped up" or "bright" sound because the highs are louder than the bass.
However, this effect can be ameliorated by using a speaker with a flat impedance curve.

