Roberto's public listening tests page

Welcome, and thank-you for your interest in my tests.

The recent developments in perceptual audio coding, including new formats like AAC, Ogg Vorbis, Musepack and Windows Media Audio, have brought competition to an arena formerly completely dominated by MP3. Users want to check out these novelties, but frequently stumble over the doubt of "What to choose?".

One of the most importat aspects to consider about a format is it's sound quality. Undesired artifacts like hissing, "pre echo" and "stereo collapse" can ruin the pleasure of the listening experience.

One of the most acclaimed methods of comparing codec quality is by performing so-called "Double Blind Listening Tests". In this sort of test, the participant compares various encoded samples against each other and against an uncompressed reference sample. The blind part means that the participant doesn't know which sample was encoded by which encoder. That guarantees there'll be no psychological bias towards his/her favorite codec, or against the codec he/she dislikes.

The purpose of this page is hosting the public tests I conduce from time to time. This includes hosting instructions, results, graphs, etc.

You can now subscribe to the listening tests announcement newsletter. Check the link for more details.

You can download all samples used in my listening tests here. They were encoded with WavPack.

NEW: You can download my entire listening test packages (except for the first AAC @ 128kbps, which I lost...) here.

The currently open test is: there's no listening test open at the moment

Here are the tests I conduced so far:

• AAC at 128kbps

  from 2003-06-04 to 2003-06-15
  • Presentation page
  • Test Results

• 128kbps extension

  from 2003-07-23 to 2003-08-03
  • Presentation page
  • Test Results

• 64kbps test

  from 2003-09-10 to 2003-09-21
  • Presentation page
  • Test Results

• MP3 at 128kbps

  from 2004-01-14 to 2004-02-01
  • Presentation page
  • Test Results

• AAC at 128kbps v2

  from 2004-02-18 to 2004-02-29
  • Presentation page
  • Test Results

• Multiformat at 128kbps

  from 2004-05-12 to 2004-05-23
  • Presentation page
  • Test Results

• 32kbps (dial-up bitrate)

  from 2004-06-30 to 2004-07-11
  • Presentation page
  • Test Results

Links:

• Hydrogenaudio general audio formats discussion forum. A very friendly and resourceful place, that helped my testing efforts in countless ways.
• ff123's excellent site on listening tests and audio quality
• ITU-R BS.1116-1 - my listening tests try to adhere to this specification as much as possible.

Aknowledgements: I would like to thank the following people

• ff123 for helping a lot with conducing listening tests, and for creating several excellent tools, one example being ABC/HR
• schnofler: for creating a very advanced Java version of ABC/HR.
• Phong for the very excellent Chunky result parser
• JohnV: for helping with hints and opinions
• guruboolez and tigre: for conducting several parallel private listening tests that ended up helping my tests a lot
• Paul Harris, Menno Bakker, Dibrom and Spoon: for providing hosting space for the sample packages
• AstralStorm: for providing the obfuscated batch script
• HydrogenAudio forum members: for all the help, sugestions and constructive criticism
• Listening test participants: without you, this page wouldn't be here

Roberto Amorim - design by Dibrom

listening-tests.freetzi.com homepage