c.d. or download?

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can someone explain the technical difference between an original 44.1 khz cd and downloaded audio? or point me to a source of info?

I can hear a difference from vinyl to cd to download, but i don't understand why the quality of playback is so different.

a sincere thanks in advance.
 
Downloaded MP3 audio is going to have a significantly reduced bitrate...normal CD audio is somewhere around 1140 kb/s, but MP3's are usually found at 320 kb/s or lower. Most of numbers quoted by Apple and such for Ipods - the "get 10,000 songs on this player!" type thing - is assuming you're using really low bitrate material. Now, there are MP3's out there ripped off the CD in what's called VBR - variable bitrate - that provides higher quality than the standard way of ripping. But it's still a step down from the original recording.

Another forum I'm on had a neat graph showing the frequency loss as you go down in bitrate, but the URL's escaped my mind right now...

Hope this helps.

~ Jim
 
If you Google "MP3" then search within results for "bit rate" , you'll find that many agree that if a CD is ripped at 1410kbps (EAC) and compressed to MP3 at 256kbps or higher, that no one could tell, by blind test, which was CD or MP3.

Try it yourself. Numbers are important for designing, but the truth is what you hear. If the ultimate goal is to keep as much information as possible forever then by all means rip it at 1410kbps and leave it as a wave. If you are downloading from a pay site, then 256,320, kbps will not dissapoint you.

My dumb ears can't tell at 196kbps. Go below that and I hear subtile differences.

Don't be RULED by the numbers. Try it on your own. Get a copy of "Exact Audio Copy" and a good converter, both free, and try it yourself.
 
davidlzimmer said:
If you Google "MP3" then search within results for "bit rate" , you'll find that many agree that if a CD is ripped at 1410kbps (EAC) and compressed to MP3 at 256kbps or higher, that no one could tell, by blind test, which was CD or MP3.

Try it yourself. Numbers are important for designing, but the truth is what you hear. If the ultimate goal is to keep as much information as possible forever then by all means rip it at 1410kbps and leave it as a wave. If you are downloading from a pay site, then 256,320, kbps will not dissapoint you.

My dumb ears can't tell at 196kbps. Go below that and I hear subtile differences.

Don't be RULED by the numbers. Try it on your own. Get a copy of "Exact Audio Copy" and a good converter, both free, and try it yourself.

just fyi, most music from the itunes music store is 128kbps. it's not mp3, but it might as well be at that bit rate.

i rip my cds to flac. storage is cheap, squeezebox is sizzlin'.


bb
 
I was looking into this just yesterday. My partner bought some tracks for me from Apple's Itunes store and blew them onto CD for me as a little gift. A nice surprise and I played the CD without delay.

Oh dear :(

I then looked into this and found out Itunes will only download MPEG4 AAC format (at least in the UK). This compresses the audio by about 90% and has a bit rate of 128kbps. CD audio is indeed 1400kbps. The loss of quality was not made clear on the Itunes site (which doesn't surprise me). I was quite appauled that there was no option to download the uncompressed track, especially as the cost per track is about the same as the cost of buying a CD at a shop.

Wikipedia has excellent info about compression formats. It turns out that the most advanced NO LOSS compressors reduce a music file by about 40%. AAC reduces by about 90%. So there is a whole lot of information disgarded. And believe me it is EASILY audible on a competent system.

Be warned if you are expecting to be able to make an audiophile CD from music you purchase at the Itunes store.
 
Just to return to the difference between formats / bitrates for a second.

This has been bothering me for a while now, "We" all spend so much time debating the techincal merits of Vinyl or CD when (128kbs) MP3 is sneaking in as the chioce of the masses. YUK!

listen of your hifi setup you *can* hear the difference between mp3, Minidisc, and CD.

CD may well turn out to be the best we ever get for new releases. SACD or DVDA are distinctly not the way the industry is going (sales of SACD's were not what were recently included in the UK charts maths)

if you download music and the file size was not 30+mb per song, information was lost somewhere along the way. (unless someone knows better in which case share - please!) the resulting sound almost always seems compressed (audiably, not just from a data POV)

A good analogy might be the everso internet friendly Jpeg vs the bitmap, On first inspection they both look fine. But, zoom in and you can see the jpeg is not in the same class.

and if that's not thoroughly depressing... Human nature & history would tend to suggest we go for convenience over quality everytime. :bawling:
 
Unless your're the type that claims they can HEAR the difference between a 10 ga and 12 ga power cord, if a CD is ripped at 1440 and compressed to 256, you will not hear the difference.

If the the music is to be kept for generations, or if time and space are no object, then by all means keep it at 1440.

EAC and a good compresion program. (LAME or FLAC) will produced music that will sound exactly like the original CD to humans at this point of evolvement.
 
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Hi David,
.... My name is Chris and I can not hear the difference between 11 and 12 Ga speaker cable ... Heck, I can't hear the difference between 10 and 16 Ga at any normal power levels (150 WPC, 4 R load).

I definitely can hear the difference between 1440 and 256 kbs! Lossy compression is not your friend.

-Chris
 
Lossy compression is a solution to a problem which shortly will no longer exist. Storage capacities and Internet data rates are increasing exponentially. A friend in another province pays $45 CDN/month for an approximately 10 mbit cable service. Canadian Rogers just rolled out 1.5 mbit wireless nationally. Habits die slowly and some people will always want 25,000 portable songs but if the number of movie DVD rips and uncompressed, or at worst FLAC, audio on Usenet is any indication the early adopters of high quality are already busy. Fingers crossed.
 
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