MP3 bitrates and sound quality

At what bitrate should you encode your MP3 files? Listening tests show that at 256kbps, you can’t tell the difference. But that’s with 2 amplifiers and big speakers. What about headphones?

I tried an experiment with my cousin, who has the best ear for music that I know. We ripped a good audio CD of his at 128 kbps. He put on a pair of headphones (the kind that fit into your ear) connected to my laptop. I played the first half a minute of the original and the ripped version 10 times, in a random order, asking him to guess which was which. Result: 5 correct and 5 wrong. He couldn’t tell the difference.

We tried again, ripping at 64kbps this time. Same experiment, and surprisingly, same result – 5 correct and 5 wrong.

Conclusion: With a pair of headphones, even a good ear can’t tell the difference between a 64kbps MP3 and an original CD. So, if you want to cram in more songs into your iPod, just re-encode them at 64kbps. You’ll easily shrink the size in half, as most of them are at least 128kbps.

Comments

Madhu 13 Feb 2006 5:05 am: How good were the headphones? Also i think the sample size is a little small:0

S Anand 13 Feb 2006 7:54 am: The headphones were cheap ones I bought in Bombay. Besides, this isn’t a sampling thing… if he can’t tell the difference, I’m pretty sure no one I know can. I certainly can’t! What I should’ve done, though, is cut the same encodings back to a CD and played it on his system. THEN we’d have really know.

Venkat 14 Feb 2006 5:42 pm: U’ll find out if played in the system. But, the purpose here is to compress in a mp3 player, which anywhich way we are using with headfones right?

sLaSh 16 Feb 2006 9:41 am: A Short History of Nearly Everything…. is that really a “English Fiction”?????

S Anand 16 Feb 2006 10:04 pm: Sorry – corrected that.

Dhar 11 Mar 2006 12:09 am: Err, was this a variable bit rate encoding or a constant bit rate encoding that you and your cousin experimented with?

S Anand 24 Mar 2006 3:42 pm: Constant bit rate. I don’t know how to encode VBR.

Milind 9 Apr 2006 12:27 pm: 1] What headphones you used? [2] What music you listened to? [3] What Soundcard was there? [4] Finally Wat is your cousin’s qualifications as far as music engineering is concerned? Please don’t feel bad, but almost any person when explained the difference, after that can tell the difference. Still you are correct somewhat in saying this. Caught off guard they almost sound same.

Vaduvur Kumar 26 Feb 2007 12:38 am: Ya,its correct. I too tried on this some time. I do not care much on this as I have a good size of harddisk.

Skip Kite 25 Mar 2009 2:48 pm: This is probably a dead topic but here goes: The whole purpose of mp3’s is so you can take them with you on small players… not so you can reburn cd’s out of them to playback on your 1000 $$$ home stereo system. I’m a bit tired of reading post after post from snooty Audiophiler’s who say “Excuse me but there is a difference in quality” when I think that most of these AP’s are not listening to Baroque, Classical or even something from the late Renaissance…(where sound quality really matters) but are probably listening to Alicia Keys, Beyonce, Lil Wayne, or any number of punk bands out today… I listen to everything between Renaissance music to Late 90’s and haven’t noticed a big deal of difference… so what’s the point of having mp3’s if you are going to encode every piece of music at 160 or higher. Shouldn’t we try and find the right settings that balance quality and size. I also did various tests with different bit rates and didn’t notice much depreciable difference so now I just encode everything at 80kbps so that I save on space and it is still pretty good to ok quality. good post S anand

M 20 Sep 2009 10:03 pm: My friend swears that on his headphones (while they are excellent quality, they can’t be better than a good stereo system), even 256 mbps is not even a high enough bitrate. I’ve never believed him. This further reassures me.

Madhu 13 Feb 2006 5:05 am: How good were the headphones? Also i think the sample size is a little small:0
S Anand 13 Feb 2006 7:54 am: The headphones were cheap ones I bought in Bombay. Besides, this isn’t a sampling thing… if he can’t tell the difference, I’m pretty sure no one I know can. I certainly can’t! What I should’ve done, though, is cut the same encodings back to a CD and played it on his system. THEN we’d have really know.
Venkat 14 Feb 2006 5:42 pm: U’ll find out if played in the system. But, the purpose here is to compress in a mp3 player, which anywhich way we are using with headfones right?
sLaSh 16 Feb 2006 9:41 am: A Short History of Nearly Everything…. is that really a “English Fiction”?????
S Anand 16 Feb 2006 10:04 pm: Sorry – corrected that.
Dhar 11 Mar 2006 12:09 am: Err, was this a variable bit rate encoding or a constant bit rate encoding that you and your cousin experimented with?
S Anand 24 Mar 2006 3:42 pm: Constant bit rate. I don’t know how to encode VBR.
Milind 9 Apr 2006 12:27 pm: 1] What headphones you used? [2] What music you listened to? [3] What Soundcard was there? [4] Finally Wat is your cousin’s qualifications as far as music engineering is concerned? Please don’t feel bad, but almost any person when explained the difference, after that can tell the difference. Still you are correct somewhat in saying this. Caught off guard they almost sound same.
Vaduvur Kumar 26 Feb 2007 12:38 am: Ya,its correct. I too tried on this some time. I do not care much on this as I have a good size of harddisk.
Skip Kite 25 Mar 2009 2:48 pm: This is probably a dead topic but here goes: The whole purpose of mp3’s is so you can take them with you on small players… not so you can reburn cd’s out of them to playback on your 1000 $$$ home stereo system. I’m a bit tired of reading post after post from snooty Audiophiler’s who say “Excuse me but there is a difference in quality” when I think that most of these AP’s are not listening to Baroque, Classical or even something from the late Renaissance…(where sound quality really matters) but are probably listening to Alicia Keys, Beyonce, Lil Wayne, or any number of punk bands out today… I listen to everything between Renaissance music to Late 90’s and haven’t noticed a big deal of difference… so what’s the point of having mp3’s if you are going to encode every piece of music at 160 or higher. Shouldn’t we try and find the right settings that balance quality and size. I also did various tests with different bit rates and didn’t notice much depreciable difference so now I just encode everything at 80kbps so that I save on space and it is still pretty good to ok quality. good post S anand
M 20 Sep 2009 10:03 pm: My friend swears that on his headphones (while they are excellent quality, they can’t be better than a good stereo system), even 256 mbps is not even a high enough bitrate. I’ve never believed him. This further reassures me.