[bside123]

Can anybody explain simply, in common language, simple terms, non-engineering talk, layman's terms... what are over sampling and up sampling? What is actually happening? What are the differences, and how do they benefit or degrade digital playback?

I've read many articles about the subject and can't seem to wrap my head around the concepts completely. Just when I think I get it... my analog brain jitters, skips a beat and distorts with inaudible high frequencies.

Not only DACs are using these terms and processes, but computer streaming, playback systems such as Audirvana, Pure Music and iTunes do as well. How does one choose? What are the best selections for music playback and why?

Thanks

[Vincent Kars]

Over- and Up-sampling are basically the same: altering the sample rate.
Over sampling is most of the time done by using a natural number e.g. 8
8-times oversampling is known from CD players.
It is a technical trick to push the aliases (inherent to DA conversion) away from the audible range.

Up- (and down-) sampling is about changing the sample rate with an arbitrary number.
Some dac’s simply play everything with the chip running at 192 kHz. Hence all input must be converted to this rate.
Up-sampling is more complex as one has to interpolate.
In the past this was often done a bit crude hence some bad results.
The Win XP K-mixer is a nice example.
Today we do have sufficient horse power to do up/down sampling sonically transparent.
Bit more details on my website: http://www.thewelltemperedcomputer.com/KB/Sampling.htm