Ewelike Guides
Audio Formats
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Summary
Audio has moved on quite a lot over the last decade. Essentially there are 4 different options, all with benefits and negatives, and although all are now digital how you use them differs widely.
The options are;
From our perspective CD still reigns supreme, it's the best compromise between ease of use, quality of sound, price and availability.
Technically DVD-Audio and SACD are tbe best formats storing very high quality music. However, you'll struggle to find the music you want and things to play them on.
For ease of use Digital Downloaded Music seems the best model, but ensure you read our section below as the music is usually of a lower format than CD and there are less things you can do with it
Compact Disc (CD)
CD is the leading format for music (even if people keep predicting it's demise) and there's no sign it'll disappear any time soon. CD stores information in a high resolution lossless and uncompressed digital format.
Although technically illegal, CDs can be "ripped" into MP3s (or AAC) for use on your MP3 player as well as used on in the car or your Hi-Fi. Yes, this involves you doing some work but you get the music in the formats you want and you get the nice artwork too
From our perspective CD is still the "best" format as it's usable anywhere, CDs are reasonably cheap and are sold in lots of places, and best of all CDs can be ripped into digital formats. The ability of CDs to be ripped at different sizes and into different formats is it's best feature - you can rip a high quality version to your PC for use with your Hi-Fi and a lower quality version for your portable MP3 player (so you can fit more songs on the device), plus you get a backup of your music incase your player/PC ever gets stolen or breaks. See the MP3/AAC/Digitally Downloaded Music section below for more info.
Sony's Super Audio CD
SACD was created to provide better quality audio than CD but has failed because it needs new SACD players to play the music and there's a limited number of SACDs available. For "next generation" audio formats SACD is the competitor to DVD-Audio.
The largest impediment to SACD (and DVD-Audio too) is that people don't feel they need audio quality above that of CD and that multi-channel music isn't very attractive to non-home cinema enthusiasts.
SACD is supported by some DVD players (especially those produced by Sony), however finding the music you want is usually more difficult.
For more information see Wikipedia's article on SACD.
DVD-Audio
DVD-Audio (aka DVD-A) was invented as the audio equivalent of DVD-Video but hasn't had the same degree of success.
DVD-Audio provides for multi-channel (up to "5.1") sound at a quality that surpasses CD.
DVD-Audio is supported by some DVD players but just like SACD finding the music you want is more difficult.
For more information see Wikipedia's article on DVD-Audio.
DVD-Video with DTS/Dolby Digital Surround Soundtrack
Recently a new idea for multi-channel audio has emerged. It uses DVD-Video discs to provide high quality multi-channel music using existing DVD player technology.
However, this format is really only of use if you have a Hi-Fi/Home Cinema setup that has a surround sound setup and an amplifier that can decode DTS (as well as Dolby Digital). Few discs are available in practise though, you can't (easily) rip the music into MP3 for use with your iPod (or MP3 Player) and you can't play the discs in CD players (so it won't work in the car).
Digitally Downloaded Music (MP3/AAC)
Downloaded music is the newest form of listening to music, you go to a site such as iTunes (GB) (where Apple have made it incredibly easy to buy music and share it with your iPod - click here to find iPods on Ewelike).
However, this music has a few downfalls but first we need a quick discussion of how music is stored for digital downloads before you can understand it properly
MP3 and AAC music is compressed and lossy (see lossless below for more information on future formats that don't lose quality). If we were to take a song off a CD directly (this format is typically called "WAV" and means to extract it exactly without compressing it) then it would be about 30 - 40MB in size (typically). As you can appreciate at this size we can't get many songs on to an MP3 player (for a 2GB MP3 player that means we can store approx 50 songs - 4 or 5 albums) and downloading songs from the internet (or even between your PC and your MP3 player) would take longer.
Instead that information is compressed (made smaller) and the compromise is that some information needs to be thrown away. This sounds scarier than it actually is though because the human ear can't hear some sounds and there are gaps in the music too (silence at the start and end of tracks and gaps between when instruments play for example), so MP3/AAC remove some of the information and compress the data to make it smaller. The relationship between size and quality is an easy one though - the bigger the file (and the higher the bitrate) the better the quality, the smaller (more compressed) the file then the lower the quality.
Bitrate is the best marker of quality (although it should be said that AAC is better quality than MP3). For MP3 320kbps (kilobits per second) is "CD Quality", 220kbps and 192kbps are typical online download (compromise between quality and size) bitrates, and many people encode their MP3/AAC music at lower rates so they can fit more songs on to their MP3 player.
For Hi-Fi the lowest quality that can be recommended is 192kbps as below that the sound quality will be noticable, while music intended for portable players 128kbps can be sufficient (as outside noise will always affect listening quality).
If you intend to start a digital music collection then make sure you start backing up your data to another disk - if ever your player/PC get stolen (or the hard disk breaks within it) then you'll lose it all
One important thing to remember is
Future Digital Download Formats
As the internet speeds up (and as storage capacity of MP3 Players grows) music downloads will likely move to lossless formats instead of the current lossy formats, and for use on your PC (if you hook it up to your Hi-Fi) these formats are available now. These formats don't compress as heavily as MP3/AAC formats, but the quality is as high as possible, the trade-off is that the size is roughly half that of an uncompressed CD song.
If you're interested then take a look at FLAC for more information
Glossary
Uncompressed formats keep the information in exactly the format it was recorded. A good example is the "WAV" format that's used by digital dictaphones (and PCs for recording from the Microphone).
Compressed merely means that the file is made smaller. Compression in the music world is either lossy (information is thrown away) or lossless (information is retained while the file size is made smaller). For music lossy formats always produce smaller files than lossless formats">.
MP3 is the de-facto standard digital music format and it is reasonably good at compressing music without affecting quality too much. See Wikipedia's article on AAC for more detail.
"AAC" is a standard used by some devices (including Apple's iPod) as it is higher quality than MP3 for the same size of file (i.e. it "loses" less iformation when encoding) - however AAC is less popular becuase it can be used with fewer devices. See Wikipedia's article on AAC for more detail.