Quote:
Originally Posted by
jaqueh 
Vague title, but does the soundcard get its information directly from the hard drive or does the hard drive first cache some on the RAM or something and then the soundcard accesses it with better speed. Basically what i am asking is how can buying a new soundcard improve a computer's audio ability if the music is played directly from the hard drive. Also, the analogy i am drawing for the hard drive and ram is from why the ipod touch has better SQ than the ipod classic, because its NAND flash v. slow HDD.
Sorry about my ignorance about this topic, it might make the post harder to understand.
The sound card can improve audio if it acts as the DAC (they usually do). The DAC is responsible for taking the bits of a digital file and drawing sine waves between them as an analog signal. It's the analog signal that's amplified and used to power headphone drivers, not the digital signal that is stored in the files. A pure digital signal would sound like a lot of noise to us.
Not all DACs are made equal, though most of them are competent. The components and circuit design can introduce noise, and make mistakes in the formation of the analog sine waves that manifest as harmonic or intermodulation distortion, neither of which are wanted. A sound card may form better sine waves than another. The amp built into the sound card may also introduce less distortion, or have different amounts of output impedance. Or, of course, the frequency response could be off, but that's not too common with amps and DACs within the audible range (unless it's intentional).
Sound quality has little or nothing to do with how digital data is accessed, via flash or HDD. Arguably there could be jitter differences, but likely meaningless ones.
