A 3db reduction in power corresponds to a 3db reduction in voltage, for a given impedance. A 6db reduction in power corresponds to a 6db reduction in voltage, for a given impedance.Almarg, you are correct. Guys, I stand corrected on this.
P1 = V1^2/R1 & P2 = V2^2/R2
P2 = 0.5*P1 & R1 = R2 = R because we are looking at the power reduction at the same location hence impedance at that point remains unchanged.
So, if we take the ratios: P2/P1 = 0.5 = (V2^2/R)/(V2^2/R)
or V2^2/V1^2 = 0.5
or V2/V1 = sqrt(0.5) = 0.707
I should have done this calc before I wrote my post - my bad. ;-O
Yeah, so if we want half the amplitude, we will find it at 6dB lower power where we'll have 6dB reduction in ampl as well. So, my earlier post on 12/04/10 is correct where I showed the digital volume versus full-scale amplitude - you will get 1/2 the voltage amplitude at setting 88 & at setting 65, you will get approx 1/8 full-scale meaning that you will lose 3 bits. If you start from 21-bits, you'll be down to 18-bits at digital volume setting 65. You will lose 6 bits at digital volume setting 28.
Dennis_the_menace, I apologize for hijacking your thread. If it is any solace to you, I think, that you already got your answer to your question (which is depends on the quality of your preamp & on your personal preferences -> cannot remember right now which members wrote these 2 apt replies).