Originally Posted by r010159
Does this mean if I do not play the music in bit-perfect mode, then there may be problems? If I select for 24-bit playback, will the software be intelligent enough to convert the floating point numbers directly into 24-bit integers? Or will dithering come into play here?
Now that I think about it, if I am not using integer mode playback, wouldn't the floating point number be directly given to the DAC with no conversions necessary?
I'm not aware of any DACs that can handle 64-bit data, be it float or integer. There are some with 32-bit capability, but here I'm not sure if it's integer or float. As far as I'm concerned, 24-bit sampling is more than enough.
Back to dithering: it's a technique of "randomizing" the least significant bits, so that the quantization noise does not produce audible artifacts and is perceived as just noise. If you would do that on a 24-bit sample, it may affect the lowest 1 or 2 bits. That means the upper 22 bits would not be affected by dithering at all. When you send that to a DAC, it will do what it can to convert it to analog, but in reality the best you can hope to discern from the components generated noise is maybe the upper 20 bits. So whatever dithering would do is going to be inaudible anyway. Some players don''t bother dithering 24-bit output at all and just chop off the decimal part, but I don't know if all do that (they should, as dithering 24-bit audio is just wasting CPU cycles).
Regarding problems in the non-bit-perfect world: the way I approach this whole thing is I choose bit perfect just for the peace of mind that the sound is as good as it can be. I'm not sure if I could distinguish between bit-perfect WASAPI playback and DS, even in 16-bit. But if you want the theoretical explanation, then the dithering done during the CD mastering is there to begin with, and combining it with the dithering in software may increase the noise level. Still, clever noise shaping algorithms should minimize the impact of this effect, and you are unlikely to ever hear it, unless you're planning to get deaf. If you hear any noise during CD playback, it's probably the tape noise from master recording - this happens a lot on older CDs.