Quote:
Originally Posted by Belsiya
(Post 293972)
... I also have iTunes set to import songs at 128 kbps. That's CD quality, anything more just wastes space on your hard drive.
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Sorry to correct you but 128 kbps is NOT CD quality. lol :D To understand how mp3's work during encoding, they limit frequency range to below 15 KHz, & often above the lowest frequencies. They reduce size from originals in a number of ways, most of which include throwing away audio information. They attempt to encode repetitious cycles so it's not continually repeated in the encoding process. They often approximate frequencies.
An mp3 file at a lower kbps means a thinning out of the sound. If you have a "very" hi quality sound system (with appropriate hi quality speakers & appropriate settings to suit the room) & play a cd thru it & then compare it with the same songs encoded into 128 kbps, you
will notice the difference. If you can't, then your hearing abilities at hearing differences in tone & subtle frequency changes are probably untrained or burnt out. lol :D It is more obvious with some styles of music or songs than others.
Several years ago there was a lot of propaganda about 128 kbps being CD quality because when mp3's first came out that's what their maximum ability was. Unfortunately many audio programs still set 128 kbps as the default setting for audio encoding. In those days people's internet speeds were much slower, & their HDD's were much smaller, so using smaller files to swap across the internet was much more desirable. Before mp3 was mp2. There were some somewhat misinformed/ignorant people who didn't have any audio qualifications who wrote articles saying mp3's at 128 kbps were cd quality. Some even saying they were better than cd quality. lol :rofl: Unfortunately that old propaganda still affects some users nowadays. (If you have an audio editor with a frequency response graph ability, compare the original AIFF/WAV with that of the same song on an mp3 at 128 kbps & you will see where some of the losses occur & how the shape of the music has in fact changed slightly. There will be less audio information for a start, & less subtle frequency peaks & dips along it's trail. The lines will be straighter, signalling less information & approximations made ... eg: combining small frequency changes between 568 kbps, 572 kbps, 558 kbps, 564 kbps ... may all show as 570 kbps in the mp3 over that short time span which might only be 0.01 of a second. Add all those 0.01 secs up on top of each other & you have some notible changes.) mp3's are designed to focus on the mid range frequencies & show most loss at the top & bottom ends (high & low sounds.) That's because most people's ears generally focus on those ranges where voice & higher guitar sounds range in tone. mp3's at higher than 128 kbps try to give more response where the 128 kbps lacks (but still below 15 Kbps) & most likely less approximations.
mp3 is a "lossy" format, meaning it throws away audio information to help reduce file size. Re-encoding an mp3 or mp4 or ogg file to another mp3/mp4, etc. is thinning out an audio file's quality even further. Throwing out even more information. I certainly hope you are not sharing those re-encoded files on Gnutella network but only the originals you downloaded. Otherwise you are degrading the quality of files shared around the network. Would you like to listen to a song that's been re-encoded from mp3 to mp4 to mp3 to mp3 (people changing the kbps each time) ? It will sound crappy I assure you, compared to the original from the CD. (Re-encoding an mp3 from 128 kbps oto 320 kbps will not improve the sound at all! The opposite! Nor will it improve if encoding from 320 down to 128.)
Since you use iTunes, I put you up to this task. Get a cd you have Purchased (not one you have burnt from mp3's.) Convert the songs to AIFF. Then convert the songs to mp3 at 128 kbps. Then listen back to the sound difference between the AIFF files & the mp3's. Listen to the AIFF ones first & 3rd. AIFF is a non compressed audio format (does not throw away audio information.)
