Correct, and doubling of dB(SPL) does not equate to a doubling of psychoacoustic volume.
If you have a decently high end audio receiver at home, let me know if going from -25dB to -22dB on the volume makes you jump out of your sofa for being "twice as loud"!
Axiom AudioFile Newsletter
Now for the really amazing part: although it seems that doubling the amplifier power in watts would also double the loudness, disappointingly it only increases loudness by 3 dB, a change in volume most of us perceive as “slightly louder.” That’s why going from an amplifier of 75 watts output to one of 150 watts output only increases the actual acoustic output a bit—again by 3 dB. To make sounds subjectively “twice as loud”—an increase of 10 dB—requires ten times as much power from the amplifier.