I have been playing with my Lumin P1 streamer settings and have up-sampled my 44.1 CD players digital input to 176.4 and the sound quality presentation is a bit warmer and smoother than the 44.1.
Thought I would share this and I am interested in other peoples experiences with up-sampling.
I found that the Naim DAC did a better job than Roon although this was a while back and things on Roon may have changed.
The nDAC does oversampling of 44.1 to 352.8 kHz.
The term is over sampling when rate is a factor of 2 times the original sample rate…. So 98.2 and 176.4 are over sampling rates of 44.1 as used by CD red book. Rates of 48, 96 or 192 of 44.1 would be up sampled and are best avoided if possible.
Oversampling is beneficial to upsampling as no mathematical errors are typically produced in the multiplication process.
Oversampling typically adds zero value samples between samples to avoid errors. This is what Naim does within its DAC reconstruction filter.
Why would you want to do this?
Typically outside of the DAC itself one would do this to change the sound from a DAC due to its performance limitations or response. A quality DAC should arguably not need any oversampling of its input rate.
Within the DAC itself, reasons to perform oversampling include allowing its lower pass filter and/or reconstruction filter to produce less artefacts, and also to reduce source jitter energy within the audio pass band. It is usually significantly beneficial to oversample within the DAC as opposed to outside it… but there are exceptions like Chord Electronics M Scaler
However because oversampling options outside the DAC itself such as in software such as with UPnP server or Roon are completely dependent on the performance of the end DAC … it’s results will totally vary from product to product… and as I say on quality replay components should be usually best avoided unless specifically designed for this sort of coupling like m scaler with Chord DACs.
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Hi Simon,
Thank you for the terminology clarification and further guidance on this topic.
The Lumin App calls changes to sampling “Re-Sampling” and for native 44.1 can also change to 88.2 and 384kHz or DSD64 or DSD128, however, I tried these and did not really hear a difference from 176.4 so left it on this setting as a noticble and preferable difference to 44.1 for me.
The Lumin App can similarly re-sample all file inputs e.g. 48kHz and various DSD’s, its a nice feature to play with and listen for differences which maybe preferable or not.
Appreciate your response and advice, very informative and helpful.
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Yes re sampling is a general term for recreating a sample stream.
Also my description above applied to PCM oversampling. The reasons why DSD must be oversampled are quite different.
Transcoding from PCM to DSD is slightly lossy process and is not usually advised on SQ grounds… as it can typically create new low level artefacts.
However in a particular set up the change to the digital audio reconstruction in transcoding PCM to DSD may suite a personal taste, although possibly less like the intended mastered sound.
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Sugden produce a DAC that has no over sampling or digital filtering. It sells for two grand.
The term 'Rescuing music from technology’ seems to be used in their advertisements
I remember many years ago converting my Rotel 855 CD player TDA 1541a DAC to NOS. Can’t say I noticed a dramatic change in the SQ. 
A good one. I keep having this recurring dream of a Nait 2 and a BorderPatrol NOS-DAC.
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