Originally Posted by rahzim
Hmm so I've heard now that it should be 100%, and 80%. I wonder if there's any scientific evidence to back this up or if it's just conjecture. I think I'll ask this question in the sound science forum. I tried adjusting volume on fubar myself and with the amp and didn't notice a difference, but then again I didn't listen very critically.
It's not a big deal usually, but it depends.
If you want bitperfect output (exactly what's on the CD / file gets sent to the DAC), you need 100% volume, no EQ or any processing, and no anything added in any part of the software. However, bitperfect is not really worth worrying about and doesn't really mean much in practice for music playback. If you have volume under 100% in software, this is essentially reducing the resolution of the information sent to the DAC. To get the values smaller and softer, they all need to be divided down; the lower you set the volume in software, the more information you're throwing away by scaling the signal down digitally. Thus you get lower signal-to-noise ratio in theory; in practice, this is only an issue if you have 16-bit playback only (24-bit, you can do pretty much whatever).
Some DACs, for whatever reason, aren't designed well and have issues running at max volume. They might clip the peaks slightly if you run them at 100% or close to it. So turning the volume down for these devices, would avoid this problem. How much you need to turn down depends on the device.
So on decently-designed hardware, 100% is better—but practically the same. To be safe, something lower avoids a potential issue and is probably negligibly worse (16-bit) or pretty much not worse at all (24-bit).
Edited by mikeaj - 6/29/12 at 2:30am