Wav and flac are both lossless, so you lose or add nothing by choosing one or the other.
However with the Naim old streamers, some people think Wav sounds better than flac - this is thought to be because the processor in the streamer has to work harder to decode flac than Wav. But with the new platform streamers, including the NDX2, the processor is powerful enough that very few people find any difference in sound between the two formats.
The advantages of flac over Wav are that the metadata is included in a standardised way and you can therefore use the flac in other players without losing any metadata and secondly flac uses less storage space as its more compressed than Wav.
Anyway the short answer is that flac is fine for your NDX2 and you would gain nothing using Wav instead.
… in the sense that a flac file size is roughly 50% of the equivalent wav file. As said before, both are lossless audio files, flac is just stored in a more efficient manner.
Just to remove any ambiguity of the word “compressed”, it doesn’t mean lossy.
And one more ambiguity- “mp3tag” software works with flac files! Ignore the name of the application.
They do sound the same, but as I explained the old streamers had to work hard to decode flac files and some people said they could detect the effect of that on sound quality. However that doesn’t apply to the later streamers because the processors are much more powerful and very few people now notice a difference.
But there is always the odd person who believes differently…
dbPoweramp can create WAV or Wave files… following the WAV RIFF standard… specifically it creates the extended wav file construct that supports hidef PCM. I have often used dbPoweramp this way.
Further dbPoweramp supports the standardised WAV file meta data format… but that was designed for music authoring/production rather than consumer ripping of CDs so the suitable attributes are a little limited… so it also supports the defacto metadata standard of ID3 tags… and dbPoweramp allows you to use both formats for max interoperability… one of the benefits of RIFF structures of WAV files.
Wavpack is a more flexible alternative to FLAC or ALAC for lossless compression, but is in a wave file construct…
When unpacked and decoded, FLAC and WAV content data are absolutely identical.
However the streamer has to work slightly harder to decode FLAC (like a PC unpacking a ZIP file) … and on some products this extra processing noise can make its way into the DAC section and change the audio balance by a tiny amount. Separating DACs from digital streamers front ends usually mitigates this if it’s audible in a streamer product. Later Naim streamer products go to some interesting design considerations to decouple this processing noise from the DAC sections… so for many the processing noise difference between FLAC and wav is not audible in these products.
However you should note the processor load for unpacking a FLAC is the same irrespective of the compression level the FLAC is encoded in. (Other than level 0 for no encoding). So there is no SQ penalty for using maximum compression FLAC, but your ripper might take a little longer to encode.
Perhaps some rippers have problems with this but it is not my experience. Even iTunes/Apple Music can rip to WAV and add artwork and basic metadata, as can Naim rippers in their own way. Still done a little differently to FLAC, as Simon explains above.
ExFAT would be my choice too for cross platform compatibility.
Avoid NTFS as Macs can read but not write without 3rd party drivers you might need to pay for. Similarly the Mac formats HFS/HFS+/APFS will cause problems if you want to share with Windows computers. APFS isn’t supported as far as I can remember on Naim streamers - options FAT32/ExFAT/NTFS/HFS but the 2nd is best for cross computer compatibility.
Personal preference for me is MP3tag, free software that I give a yearly donation to the author as he has kept it going for a number of years - it will auto convert to flac once you install the flac exe somewhere. I use this with a few online tagging systems sush as freedb and discogs - warning - correct tagging of music can be quite obsessive!
Warning 2: it is far easier to check and if necessary correct tags immediately, or when there i no more than a handful to do. Leave until you have several hundred files, as I did having been oblivious to tge need for metadata (initially I simply browsed and selected by file name and methodical file structure), and it becomes a major, soul destroying task. In my case trying to find and correct several hundred albums with incorrect, inconsistent or missing metadata saps my will to live, so I have not done it and soldier on regardless. (What I don’t understand is the reluctance of some (maybe most) playing/library software writers to facilitate searching and browsing by file name and structure.)
The other great piece of free software that I use (its free for personal use) is Bulk Rename Utility - this is excellent if you have a load of files with irrelevant characters in them, or you want to standardise their names etc
