(Latest update: 2026-Apr-09)
Introduction
I have looked into audio data resampling on multiple occasions over the years. It is one of those topics that simply keeps popping up, whether you want it or not.
In my case the trigger was simple. One of my DACs internally converts the incoming data to a higher sample rate. That raised the obvious question whether it might be better to do the resampling outside the DAC, using a high-quality software resampler and filter settings of my own choice.
With the renewed interest in NOS and R2R DACs, the subject has gained new relevance. The question is no longer just whether resampling happens, but where it happens, how well it is done and what trade-offs come with it. Basically if you don't feed a NOS DAC with HiRes data, you'll face aliasing effects.
Applying a slight resampling of e.g. 2x to 44.1/16 base data might be worth the effort.
During my research I found a lot of fragmented information, plenty of marketing talk and very little that helped build a practical overall picture. This article is my attempt to bring the relevant pieces together: what resampling is, why it is used, what it costs us, what a DAC might already be doing behind the scenes and how I approached the whole thing in practice by using the still state-of-the-art audio tool Sox and for real life playback the Lyrion Media Server (formerly known as Logitech Media Server).
As an engineer, I mainly look at the theory and mathematics behind the filters, at measurements and at the practical compromises they reveal. But I also consider listening indispensable. In my own tests I do hear differences between certain algorithms and settings. What I cannot yet fully explain is which measurable mechanisms are responsible for that perception in real music playback. To me, the gap between theory, common measurement practice and actual listening experience is still not satisfactorily explained.