Coming from a Pioneer CD without stopping to think about the dB scale, my initial impression was the the output of the empeg was not as high. i.e. On the old CD 20/40 was really as loud as you want to go while sitting in the car. Where as with the empeg I felt the same level is reached at around -10dB.

I had to then dredge up my lanquishing physics to try and understand what I was looking at. Basically all the voltage change is at the top end.
P = 20 log(V / Vmax), where Vmax is 4V.

So at -6dB the empeg is only at half of its maximum output voltage!

But what does this mean in terms of perceived volume, if I go from -6dB to 0dB, is it twice as loud?