Why do Wav and Flac Files Sound Different?

wav does not contain metadata while flac does

Um, beg to differ.  You are correct in that the existence of album art or metadata should make no difference to a properly behaving streamer.  Perhaps @audiotroy  you are conflating album art with metadata?  I just converted a file from FLAC to WAV and it had artist, album, year of release, etc. but the album art did not make it over.

I found this interesting article on album art however, and it seems this is a rather new capability for WAV files.

Important to note that some metadata is required for WAV and FLAC as it describes the data in the audio data container that explains how the stream of bytes should be interpreted.  Floating point vs. integer, number of channels, sample rate, etc. is all necessary for WAV files and part of the file format definition you may read more about here.

There is a second, optional part of metadata associated with human legible, descriptive tags.  Not actually needed to play a file, but certainly needed to organize a music library. 

It may help to think of an audio file as having 3 parts:

• Metadata needed to read the byte stream and it’s location in the file
• Optional metadata about the recording (Composer, artist, year of release, lyrics, album art)
• The music data byte stream

Each of these chunks of information are entirely separate in the file, so as @audiotroy points out, the existence or absence of album art should make zero difference to the DAC.

The byte stream presented to the DAC should be identical regardless of optional metadata or indeed file format (FLAC, WAV, ALAC, etc.).

The one possible/plausible area I can see FLAC vs. WAV causing a difference is with poor streamers that don’t implement decompression (FLAC or ALAC) with adequate buffering and that somehow the time taken to decompress each chunk is affecting the rate at which samples are presented to the DAC. IMHO, this is possible, but certainly signs of poor design, not a feature of the file format.

If there IS a difference in a file because it has or does not have album art that would be a significant functional error/bug.

To end with a metaphor, imagine a vinyl record. The metadata is the text on the label. The cover art is on the cardboard sleeve, and the byte stream is the music in the groves. If you can hear a difference in an album because of the sleeve art you really have surpassed the boundaries of human capabilities.

I am using dbpoweramp to rip all my cds to WAV. I’m getting metadata and album covers which show up on my Aurender. Not sure why people say you don’t get these with WAV. Does dbpoweramp do something special? Or am I seeing something else?

@m2team00  It seems to be a relatively new feature to have album art in WAV files and not sure all converters support it.  See more here.

Well I guess I lucked out getting dbpoweramp to rip my 1500+ cds! Took me 6 weeks at 4 hrs a day!