Mon Apr 23, 2007 12:38PM EDT
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When you rip music from CD, you're asked to make many choices: compressed audio format and the bit-rate of the compressed file being the chief among them. This latter choice is a biggie: Do you want, as iTunes would have you believe, "good quality" at 128kbps, "high quality" at 160kbps, or "higher quality" at 192kbps? Or something even higher? Or do you want wholly uncompressed files, which keep every bit of data on the original recording?
This selection isn't just critical because it can affect the quality of the audio you ultimately hear. It's also a big determining factor in the size of the file. A four-minute song encoded at 128kbps will consume about 3.7MB of space. That same song at 192kbps will eat up 5.6MB and a whopping 10.5MB at 360kbps. On a 20GB iPod, that means you can store about 5,000 128kbps songs but only 1,750 360kbps songs.
So, the big question... what does bumping up the quality of a music rip get you? Maximum PC took a bunch of non-techies, outfitted them with headphones, and ripped their own music at 160kbps, 320kbps, and a lossless format. The editors then asked each tester to blindly listen and rate the tracks as good/better/best... the idea being that the lossless track should sound much better than the lowly 160kbps track.
How do you think they did?
Not very well. Each of the testers got some right and some wrong: But most testers were simply unable to tell the different between a 160kbps track and an uncompressed one at all. Whether that's because encoding works better than we all think or because our ears are universally busted, even lower-grade digital music is still good enough for most eardrums.
One takeaway from the Max PC piece: variable bit rate recording makes a huge difference. You can turn this on in iTunes by using a "custom" encoding setting and checking the "Use Variable Bit Rate Encoding (VBR)" box.
Try the experiment for yourself sometime and see what you think. In my experience, the quality of your headphones is much more important than the way the music was encoded.Â
Join in the discussion. Here you'll see the comments in the order they were posted.
Yeah, headphones are no good test. I can tell when I hear 128 kbps files in my car.
johnnyrafes - the last page of the linked article has detail on why VBR is important
Chris, Thanks, I missed the link on the first read. Very good article. My comments concerned the Yahoo subscription tracks. I think they are CBR but should be VBR. I'm kind of sorry I signed up for the YMTG for two years. I listen most often in my car or home through the highly rated Zen Vison M and at higher volumes the tracks have noticeable distortion. I also tried using the ZVM on many other sytems so I know it's not my car and home systems. Also, tracks ripped with YJB at VBR sound much better. Maybe Yahoo should switch to VBR encoding. Johnny
Headphones are a great test, with a good pair of 100 dollar headphones you can hear much much more than you ever could in a car or any other speaker system that you could hope to afford. Also, I hope they used a good pair of headphones, and didn't play the songs through an Ipod (I haven't tested bitrates, but the different between my home stereo and my ipod playing the same MP3 is vast. The ipod itself just can't play high quality audio. Also to answer a previous posters question, Variable Bit Rate sounds better because it conserves file sizes when it can (boring passages or bits without a lot of variation) and bumps the quality way up when it needs to (like when lots of instruments are playing in a widely varying manner. (Which is when you hear the differences in bitrates)
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1 Posted by johnnyrafes on Thu Sep 3, 2009 4:39PM EDT Report Abuse
While I agree totally with the findings reported here, I think the results would be entirely different if the test was performed with an amplified source such as a car or home stereo. I've notice that songs that sound great with headphones (at 192)sound noticably inferior in the car (when compared to the original wav files on the CD). Not sure why but it is evident. Also, could you explain more why the variable rate sounds better ? I thought it was only an issue of smaller files. JR