CDP voltage output...what does it mean to volume?

Bottom line, 10 db SPL doubles the output. 70db is twice as loud as 60 db. 80 db is twice as loud as 70 db. 90 db is twice as loud as 80 db, etc, etc, etc.

No, no Jmc.
As Peak & others note, it is generally accepted that 10dB SPL "SOUNDS" twice as loud (or half, depending how you look at it).

In sound pressure terms (SPL), +6dB is double the sound pressure.
In order to achieve +6dB SPL you need 4x the power.

Also, looking at the formulae Peak's posted, you'll see that 20dB (SPL) is 10x louder (3,16^2).

A difference of 20dB SPL= 10 times "louder" (i.e. sound pressure level). A difference of 40dB SPL= 100 times louder... etc.

Ultimately the confusion stems from the fact that there is a difference between intensity and sound pressure level. You need 4x the intensity (energy/watts) to achieve 2x in spl terms. A difference of 10dB (SPL) is 3,16 times louder... a difference of 20dB (SPL) is roughly 3,16 x 3,16 louder...
You need x10 watts to achieve +10dB of sound pressure... so, 10watts => +10dB spl, 100watts => +20dB spl, 1000w=> +30dB spl (and the speakers have kicked the bucket long ago).
Cheers

This link to Stereophile may help clarify things. On reading through the various posts, I can say that jcmcgrogan2 has got it right. There is something in Gregm's post that might confuse things more...but I'm not sure. I find myself turnig to Wikipedia more and more these days as it is peer review and continuously edited to fairly accurate on most issues...truly an amazing resource enabled by the internet.

cheers,

Here are a couple of more links to sort this out:

Crown amplifiers and dB

Relation ship between dB and perceived volume

I'm hoping to resurrect this thread after being dormant for 13 years.  I too am confused by output voltage from different sources and how it relates to volume.

I have a Parasound D/AC-1600 which states it has an output voltage of 6.0V through the balanced output.  My Theta Pro Gen Va has a stated output of 7.0V through the balanced outputs.  You'd think the volume of the Theta would be "louder" than the Parasound, right?  Well, it's not.

Through my Pass XP10 inputs 1 and 2 (both balanced inputs) when you switch back and forth, the Parasound is about 6 clicks louder on the volume knob (6 dB?).  I've had other DACs hooked to the balanced inputs that were lower output voltage, and they (as expected) were not as loud as the Parasound.  Could the specs be wrong on the Parasound?  Any other explanations?

Sidebar:  how cool would it be if you could preset the volume on your preamp to different levels by input so you could volume match different sources - does that exist?

marlin38

... how cool would it be if you could preset the volume on your preamp to different levels by input so you could volume match different sources - does that exist?

Oh yes, McIntosh has offered that feature on many of its preamplifiers for years.