Quotes from varies websites
I went ahead and randomly collected quotes from different websites to see what views people had on this subject.
Sounds & Visions Online
A rate of 128 kbps is usually considered near-CD quality; CDs stream data at more than a megabit per second, but itÂ’s tough for many people to distinguish between CDs and 128-kbps MP3 tracks. Still higher data rates. like 192 kbps, win over audio professionals. According to sound engineer John Seymour (whose credits include Dave Matthews and Alice in
Chains), 192-kbps MP3 tracks ripped by RealJukebox Plus are "effectively indistinguishable from the original CD."
MacAddict
When compared to the original audio, the quality of the file encoded at 128 Kbps in MP3 is generally acceptable, except for certain high frequencies (such as hi-hat cymbals), which begin to sound warbly.
WebMonkey
For higher quality sound - and bigger files - you can encode songs at 192 Kbps, or even 256 Kbps (which is true CD quality).
Better yet, most MP3 encoders offer "variable bit rate encoding" which is a good way to maximize sound quality and file size simultaneously. In variable bit-rate (VBR) encoding, the software analyzes the data and determines the optimal bit rate for encoding each frame of sound. For instance, cymbals are troublesome for MP3 because they represent "white noise," or a combination of many different frequencies of sounds. By contrast, a bass drum beat has a fairly straightforward frequency that can be easily represented in MP3. So when a song is encoded using VBR, the program analyzes the data and works within a range -- say, 128 Kbps and 192 Kbps -- to find the optimal encoding rate for each frame of sound. The end result is an MP3 file that is optimized for both size and sound quality.
MP3software
Aw heck... this is another of those questions that people debate *endlessly*. There really is no one answer - it depends on your ears, your equipment, etc. I think it's probably fair to say that 128 Kbps is a bit on the low side, although it may sound fine from some encoders for some songs under some circumstances, whilst 160 Kbps done by a good encoder should sound pretty good to most people under most circumstances... *but* I know some people will insist on higher standards. Different encoding software really does make a difference - some encoding software produces results that sound pretty awful to me at 128 Kbps, whereas other software produces ok results... e.g.
As to what MP3 encoding rate can approximate to CD quality data to the satisfaction of a listener - well that's the part people argue about endlessly. It depends on the individual listener, and on the playback equipment and the circumstances. I think it's fair to say that few people feel that a rate of lower than 128 kbps is adequate. A lot of people find 160 kbps good enough, but some still hear problems and go for higher rates. Also all encoders are not equal, allowing more room for discussion (that is encoder X may produce much better sounding files at 128 kbps than encoder Y).
mobile enertainment
Sound quality, of course, depended on the encoding bitrate, as well as the quality of the encoding software itself. Tracks recorded at 96 kbps (kilobits per second) started to sound pretty decent, tracks at 128 kbps were pretty good, and tracks above 192 kbps were essentially CD quality. The sound quality of any MP3 file is mainly dependent on the encoding conditions, but the PADVD-500 provided good MP3 quality without any obvious contributions or omissions of its own from the decoding process.
btw: someone mentioned that women seem to be able to hear defects more than men because they tend to have better hearing.