- A few days ago, a customer wrote me to ask my opinion on why he couldn't hear any difference between an audio file produced at 44.1kHz/16bit and the same file upsamplet to 192kHz/24bit. He thought that the upsampling process would improve the sound quality of the file. While it could be marginally so when it comes to the way a DAC and its output filters work at different sampling rates, one thing must always be clear: upsampling doesn't add information nor improve the inherent sound quality of a file. Upsampling means changing the sampling frequency of a file to a higher one. Typical is going from 44.1kHz to 176.4kHz. A side effect of this process is that the resulting new samples fit on a larger word than the original ones, so 44.1/16 generally translate into 176.4/24. Does this mean that we have more information in the upsampled file than in the original one? No. Let's see why, discussing about bandwidth and resolution. The original analog program has been heavily band-limited prior A/D conversion. Converting it @ 44.1kHz required band-limiting @ 20kHz or so. All information beyond that frequency were lost forever.