Sunday, 30 September 2012

The Great WAV vs. FLAC Debate (Part 1)

There has been on-going debate over recent years that even though FLAC (Free Lossless Audio Codec) files use a lossless compression, on playback they still don’t sound as good as an unpackaged & uncompressed WAV (wave) file. The WAV file encased in the FLAC container, although compressed, is still bit perfect – and when unpacked by the music server/source it should be in every way identical to an original WAV file that has not been encased in a FLAC container. However many audiophiles have argued there is a difference that can be heard.

I will be honest here – I'm a sceptic – since the FLAC file is unpacked and the WAV file in either instance is effectively send as a digital PCM stream to the DAC doing the decoding I cannot accept there is anyway one could sound different to the other – if everything else is identical (same server/source, same original file prior to being compressed into a FLAC file, same cables, etc). However two things have prompted me to do my own trials to see, as enough (sensible) people have expressed the opposite opinion to suggest it can’t all be psychosomatic, and there is now a FLAC Uncompressed option for the FLAC format – essentially meaning a WAV file can be encased in a FLAC container for tagging purposes, but has no compression applied to it.*

* Note that while FLAC has a compression setting of 0 it doesn't actually mean there is no compression. FLAC software can be set for compression values of 0 to 8 (or 10), the default being 5. While 0 creates a larger file than 5 for example, it is not very much larger, and is not as large as a WAV file. For example, Alison Krauss and Union Station’s “Paper Airplane” (at 24 bit / 96kHz resolution) has the following sizes:
  • Compression level 5 FLAC: 76,247,040 bytes.
  • Compression level 0 FLAC: 80,240,640 bytes.
  • Uncompressed FLAC: 124,969,984 bytes.
  • Original WAV File: 124,919,808 bytes.

So Can FLAC And WAV Sound Different?

    So I decided I’d try out a bit of a comparison – I took 3 Alison Krauss tracks off Paper Airplane (at 24/96) and 3 each of Eleanor McEvoy's Yola and Rachel Podger's Orchestra Of The Age Of Enlightenment (both 16/44 rips off the CD layer of the respective SACD releases). These were all FLAC 5 compressed - so I created FLAC Uncompressed and also WAV versions of the files using dbPowerAmp. I then listened to all 3 versions of each track (so 9 songs, 27 tracks on total).

    While I am not convinced my initial listen was overly scientific I was immediately struck by what appeared to be an audible difference, my initial impressions being:
    1. FLAC Uncompressed & WAV seem to have slightly enhanced mid-range over FLAC 5 Compressed - the mids seem to be a touch 'richer' and have more depth (or perhaps body). There's also a slight sense of more detail, or perhaps texture, in the upper minds (i.e. guitar & violin strings, some vocals). This seems to match other audiophiles' reports of Compressed FLAC sounding stretched or thin compared to WAV.
    2. WAV did not appear to sound obviously better than the FLAC Uncompressed version in any way... This would suggest that if there is a difference then FLAC Uncompressed would be a viable enhancement over straight WAV for tagging purposes.
    While this is in no way definitive it suggests enough to properly investigate it further – sufficient that I will go back and do a more detailed critical listen & test. Something I hope to do over the next week or two and post my findings here.


    1. I have done this comparison and do not hear a difference. I think there should be a difference but it must be very small. The CPU must read the Flac file and this is not as easy as reading the Wav. I think if you did your listening manipulating the CPU (eg locking 3 out of 4 cores on a 4 core processor) the difference may be more discernable. When doing a build for a PC that plays music (I have done 3) you can do tweaks that make it better for music. One of those is to have a good low power processer, another is to have lots of high speed ram (1600 is a minimum) and thirdly to play the files from memory, not from the disk. The are heaps of other tweaks as well, but I doubt you will hear a difference between flac and wav running on a well designed PC running at 3+ gigahertz.

      Andrei (

    2. I ripped a 32-bit WAV copy of 7th heaven, which is one of my fave tracker modules, and then ripped a FLAC copy, soundtested both, and didn't hear a bit of difference between the two, and the WAV copy was HUGE! Freaking 221MB vs. the 64.59MB FLAC version, so the only real difference between WAV and FLAC is FLAC is smaller, and it can be uncompressed into a WAV and have all its info intact.

      1. Hi Josh - yes I have found little difference (at least that I can detect) and haven't pursued it in any greater depth - hence I haven't posted further on this subject over the last year. However Andrei above may be right and it may be a very subtle difference and may require very specific CPUs & DACs to make it detectable by human ear...?