FLAC or mp3, which download format?


Across the internet there has been much debate about which format to rip or download music on to your computer. Some say you can hear no difference, some say the sound is totally different and mp3 is no good. I wanted to find out for myself what I can hear. Having done the test I have been meaning to put it on the internet for myself and for anyone that is interested.

To test properly you need two identical high quality digital music players. If you listen to one version and then have to change tracks to get the other one you will forget what the first one sounds like. I had one squeezebox touch and last year I got another for another room so now I have two the same. Sadly now discontinued, the squeezebox touch is generally known to have very high, some say audiophile, sound quality. I would consider it to reproduce the sound pretty perfectly. I plugged both of these into my amplifier so I can switch between the two different rips on the two players, which I carefully started at the same time, of the same track using my remote without moving in my chair for an instant A/B comparison.


All tests use CDs ripped to FLAC (16/44) using EAC versus the same CD ripped to mp3 at various bit rates. I have typed up the notes I made at the time.

Test 1. 30th Sept 2012. Playing Norah Jones – Feels Like Home. All the mp3s are Constant Bit Rate (CBR).

  • 320kbps CBR. I could hear no difference. This is essentially perfect to my ears.
  • 256 CBR. Again I can hear no difference.
  • 192 CBR. No difference.
  • 128 CBR. I can hear a slight difference but it is still hard to tell this apart from FLAC. 128kbps mp3 sounds slightly fuzzy and the FLAC has more detail. These are tiny differences.

Test 2. 3rd October 2012. Playing Pink Floyd – The Division Bell, Track 2 (what Do You Want From Me). CBR and Variable Bit Rate (VBR). I wanted to try more bit rates below 192 as well as VBR to find out the limit of where I can tell the difference and if VBR is better. It is supposed to be.

  • 192 CBR. Again this is perfect.
  • 160 CBR. Essentially perfect. I can hear no difference.
  • 128 CBR. It’s not perfect but it is hard to tell between this and FLAC. 112 CBR. A tiny lack of definition and detail. OK-ish.
  • 96 CBR. The sound is mushy and undefined. Not the full ticket. It gives a good impression of the music.
  • V2 (Standard) Variable Bit Rate (VBR) mp3 170-210kpbs. This is essentially perfect.
  • V4 (Medium) VBR 145-185. I could possibly hear some tiny differences in sound. Very close to perfect.
  • V5 VBR 110-150. Not the full ticket. There were obvious differences in sound.
  • V6 VBR 100kbps approx. The sound was grainy and noticeably less sharp. You could say this is OK or Acceptable.

My conclusion is that mp3 is just as good to my ears as FLAC or WAV at bit rates of 160kbps CBR or better. Variable bit rate mp3, V2 (170 – 210kbps) or V1 or V0 (best) are all perfect to my ears. At these bit rates or higher mp3 sounds the same as FLAC, CD or WAV to my human ears.


There is a discussion here on Amazon and mp3. Apparently Amazon use V0 variable bit rate which is fine to my ears. http://www.amazon.co.uk/forum/mp3/ref=cm_cd_dp_rft_tft_tp?_encoding=UTF8&cdForum=Fx28IXQIV6LBRU4&cdThread=TxFKAVQE06SKCE

Further reading on sample rates here: https://www.mojo-audio.com/blog/the-24bit-delusion/