Back in June, I challenged readers to see if they could tell the difference between the CD and MP3 versions of various audio samples. I created the test in response to people who insist that MP3s are audibly inferior to their CD counterparts. I wondered, if presented samples in a blind test, could people really hear a difference?

So far, only two people have gone on record with their guesses -- a former sound engineer named Tyler who identified two of the six songs correctly and another user who couldn't tell a difference.

But how about you?

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TAKE THE MP3 CHALLENGE!

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Can you tell the difference between an MP3 and its CD version? Try this test to see.

Whenever I write about MP3s, I invariably receive comments from people decrying the quality of the compressed audio files. So I thought I'd put together this MP3 Challenge to see if the people who complain really know what they're talking about. I was one of those people -- until I got past the regurgitated arguments against MP3s that stemmed from the early years, when they really were bad. The key with MP3s is the bitrate -- the higher the number, the better the quality (and the more space the files consume on hard drives). Amazon and iTunes offer most downloads at 256 kilobits per second -- good enough for most people. The highest bitrate is 320kbps, available at several classical music sites and what I've ripped my collection at.

Of course, even the highest bitrate MP3 -- a compressed audio format -- doesn't offer the lossless (that is, uncompressed) audio quality of an original CD track. But can you hear the difference?

The samples below reflect a variety of musical styles and recording (actually, production) quality. Click on each link to hear the samples, which are randomly ordered, or right-click on each link and use "Save Target As" to download the file. Compare them, and then post a comment telling me (1) which selection is a 256kbps MP3, (2) which is a 320kbps MP3 and (3) which is the original CD file for each sample. You should be able to play the files directly through your computer. But you can also connect your computer to play through a home stereo, listen using headphones or download the files and burn them to a CD for scrutiny.

(All of the files are in the lossless WAV format. I edited each ~30-second sample as a WAV file. Then I saved that file at both MP3 bitrates. Then I saved those MP3 files back to WAV format, preserving the audio quality of the MP3 version while creating the blind test of seemingly identical files. )

This should be easy, right? Try it and see. I'll post the answers at some point later.

1. CONTEMPORARY POP
"Hollaback Girl," Gwen Stefani
Here's a 2004 recording from Love. Angel. Music. Baby. that all the kids should know.
Sample A
Sample B
Sample C

2. ACOUSTIC ROCK
"I Never Thought I'd Live to Be a Million," Moody Blues
This is off the 1969 album To Our Children's Children's Children, from the recent remaster prepared for SACD. The Moodies were known for using state-of-the-art recording equipment.
Sample A
Sample B
Sample C

3. ORCHESTRAL
"Ruslan and Ludmilla Overture," Mikhail Glinka (Fritz Reiner conducting the Chicago Symphony Orchestra)
Reiner made many classic recordings for the esteemed RCA Living Stereo series. This 1959(!) performance is taken from the 2004 SACD remaster.
Sample A
Sample B
Sample C

4. CONCERT BAND
"Rocky Point Holiday," Ron Nelson (Jerry Junkin conducting Dallas Wind Symphony)
This concert-band gem was recorded in 1996 for Reference Recordings, a high-end classical label that also has several Minnesota Orchestra releases.
Sample A
Sample B
Sample C

5. JAZZ
"Freddie Freeloader," Miles Davis
This is from the trumpeter's classic 1959 album Kind of Blue, as remastered a few years ago for a DualDisc release.
Sample A
Sample B
Sample C

6. SPOKEN WORD/INSTRUMENTAL
"The Eve of the War," Richard Burton
This is taken from the opening of Jeff Wayne's Musical Version of The War of the Worlds, one of the first 48-track recordings. The 1977 album was remastered for SACD several years ago, the source of this sample.
Sample A
Sample B
Sample C

Note: Yes, there are other compressed audio file formats, such as Ogg Vorbis. But MP3s are by far the most popular. This is just about MP3s. Claims about how LPs offer better sound quality than anything else aren't relevant to this challenge, either. Let's just keep this to MP3 quality, please.