"Best" file format for CD ripping

Is there a general consensus on the preferred file format for ripping CDs? Before I embark on a large re-rip project, I’d like to understand what’s best (subjective, I know) in terms of file format. It seems in the past that FLAC is the most compatible, size-efficient, and metadata friendly. Is there anything I’m missing on this one?? Sonically, do they lose out noticeably to any other formats??

Will keep the collection on an external drive for now and stream via UPnP to any of my gen-1 streamers (UQ, 172, NDX)

As always, many thanks in advance!

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Nothing to consider, FLAC is the only format as per your reasoning, unless that is you are 100% locked in with Apple & iTunes.

I used to be WAV as its the best for SQ on the first generation Naim streamers.
When Asset UPnP launched the Synology version I went to that as it has an excellent feature to transcode all codec formats to any other as it streams.
I then batch converted all WAV to FLAC and now have Asset set to stream FLAC (play as) WAV on my NDX.


Thanks Mike - thought you’d be the first to wade into this one :grinning:

So your re-encoded FLACs are comparable SQ-wise to the old WAVs?

Yes … but to be clear on this, I have Asset UPnP loaded on my Synology NAS, Asset has transcoding software that converts as it streams (known as ‘on the fly’)
So my strored FLAC are sent to the NDX as a WAV.

another reason to get Asset UPnP then…was just considering that earlier today as I need to purchase dbPoweramp as my trial has expired…

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WAV sounds better than Flac,when I have compared.


I do exactly the same as Mike. Rips are done to Level 5 Flac and then transcoded to WAV on the fly ie when they are being played. WAV should sound better on first gen streamers such as your NDX. With the newer stuff it makes far less difference, if any.

That will depend on what you are playing them with. From a digital sample content perspective they are bit perfect identical.

The most universal lossless compressed audio file format is FLAC… so makes sense to use that on its highest compression. ALAC is similar and so is Wavepack (lossless), but these are not generally as widely recognized as FLAC. Naim streamers do recognize ALAC however.

The key thing is that these formats are lossless so the sample data is identical… it acts like a ZiP file used in software downloads.

However playback devices tend to use different software routines to unpack these files, and this can lead to sonic subtle differences on playback specific to a particular device and encoding type, such as FLAC/ WAV/ ALAC. Naim first generation devices were rather sensitive to this, but have massively improved with later and current products. First gen devices were happier with WAV because of certain limitations in the designs.

With FLAC choose the highest compression level assuming your ripper doesn’t become too slow. From a decode perspective, the same algorithm to unpack is used irrespective of the compression level and the same processing effort is expended… it’s just it has been packed more efficiently with higher compression at rip time.


I understand from a paper I read a few years ago that FLAC compression levels are only a time variable when encoding.
Decoding time is the same/similar irrispective of compression level.
That said, I still use level 5 as its the dBpoweramp default.
I accept downloaded FLAC files at whatever compression level they are delivered at.

Greater chance to get a good sound without compressing and then de compressing the file,that´s why it’s better to use WAV,I think.

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I think you might be thinking of MP3 or AAC which are lossy.
FLAC, WAV and ALC etc is just a different way of storing the sample data in file format in a fully recoverable format. The data contained is identical… its just WAV has a lot more redundant space in the data containers, where as FLAC removes this space. (remember we are talking about the data encoding payload - not the file itself) Of course this can mean WAV has a downside in more network noise is created per second of sound compared to FLAC… but FLAC may contain more CPU processing noise per second pf sound compared to WAV on some renderers - depending on algorithm… swings and roundabouts. The best approach is to decouple network and encoding types from the rendering quality - and Naim have gone to huge effort in doing this in their second generation streamers and later - and when you use a decoupled DAC on the NDX2 for example you are completely isolated from the vagaries of lossless encoding types and data throughput efficiency… which is how it should be in my opinion.

indeed - I ended it up putting compression to full. On modern computers the extra ripping time is trivial - and the NAS space saving can be worthwhile over many CDs

Even with the new platform Wav is superior,sound wise in real life.

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The FLAC Vs WAV debate has been discussed many times on this forum over the years.
I used to use WAV and I compared FLAC Vs WAV on my Naim HDX and preferred WAV.
HOWEVER, using FLAC as the stored file and “transcoding to WAV” on playback, I couldn’t hear any difference on my system (at the time HDX/XPS2/252 Supercap/3 x 250/SNAXO 362/Supercap/NBL’s).
I have subsequently bought an NDX2 and playing FLAC vs WAV Vs FLAC transcoded to WAV, they all sound the same on my system.
Therefore, all of my rips are now FLAC, which also has the added benefit of when I take my digital library to another place, or use it in my car, all metadata displays nicely and sound terrific. It is also compatible with some old Sonos and B&W wireless speaker units in guest bedrooms.
I’d say to you, rip as FLAC but if you’re unsure, try a few, listen for yourself and compare FLAC Vs WAV tracks to see what you think personally.

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Yeah in real life on my NDX2 I found FLAC sounded very slightly preferable to WAV when I used the inbuilt DAC… it was the other way around on my NDX… also my NDX sounded better with certain UPnP servers… I did look into that… and found correlations between inter frame timing and preferred sonic performance… I shared that with Naim at the time when they were developing the gen 2 streamers.

Decoupling the DAC with the gen 2 streamers mitigates all that now in real life… well certainly home network connectivity and encoding format of ALAC, WAV vs FLAC.

FLAC is the way. It’s non-lossy, smaller in size and allows tagging.

Indeed, though remember obviously WAV supports tagging, in fact it supports a more comprehensive tagging set compared to FLAC however the main WAV tagging is more oriented at content creation, but some non Microsoft operating systems do not always decode the RIFF chunks…
The main benefit of WAV is for when you are wanting to process files very quickly in real time and it also supports add ons and extensions, so as a file format is extremely flexible… however this advantage tends to be more commercial/industrial rather than domestic uses… other than that FLAC for storing rips or consumer music distributions is the way to go… unless you are in the Apple ecosystem, then ALAC (Apple’s version of FLAC) is the way to go. But it’s worth remembering you can convert FLAC to ALAC and back with no loss of information what so ever… the same for WAV should you need to.

thanks guys - this is exactly the info I was looking for!!

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With my 272 I could perceive a difference between FLAC and WAV, with the latter sounding superior. I believe this would also be true for all streamers using the old platform. So I set the server on my NAS to transcode FLAC to WAV “on the fly”. This can be done with MinimServer as well as Asset.

With my Atom as well as my Linn and Auralic streamers I can’t detect a difference.