Earlier in the year I started a series on digital music and how to play it. Sorry for the hiatus but I'll continue with it now...
In case you thought the technical aspects of the hardware associated with a hi-fi system for digital music replay were complicated, I should warn you that the coding aspects of music file formats as well as the replay software is a total nightmare. I'll try to gently demystify it for you here and also make a few recommendations.
Music File Format
The number of different music file formats available is mind boggling and a comprehensive review is outside the scope of this article. If you want to know more I suggest you read up here, here and here. However the first practical thing you need to know is that these files come in two basic formats: "Lossy" and "Lossless". Within those categories there are several subtypes. Here is a brief overview.
These are compressed files. The are compressed from the master recording for two reasons (1) to save storage space and (2) to enable fast downloads. However the compression comes at a price: details of the music are lost and the sonic degeneration can be quite marked, especially if the listener is using anything but earbuds. Lossy (I hate that term as well as the format) include:
MP3 (MPEG 2 Audio Layer 3). This is a digital media format designed by the Moving Picture Experts Group and is the most common form of music file. Most downloads from Amazon are in MP3 format and it is used by numerous other sites. Highly compressed: an MP3 file is about 10% of the size of an equivalent file on CD.
AAC (Advanced Audio Coding). Can be regarded as the successor to MP3 filetypes although is somewhat sonically superior. Often though of as a proprietary Apple format but in fact was developed by a consortium of companies and can be played on non-Apple devices. Most downloads from the Apple store are in AAC format.
WMA (Windows Media Audio). This is a proprietary format from Microsoft for use with the Windows operating system.
OGG Vorbis An open sources codec. It's the format used for some streaming internet radio stations such as Spotify. There are several quality levels although I think this is mostly academic from the perspective of those building a music file collection.
Lossless formats can be compressed and uncompressed. I'm not going to differentiate here as the sound quality is unaffected. The most commonly encountered ones are:
AIFF (Audio Interchange File Format)
ALAC (Apple Lossless Audio Codec)
FLAC (Free Lossless Audio Codec)
WAV (Wavform Audio File Format)
Which Format to Get?
Well assuming you are going to avoid lossy formats wherever possible, you are going to acquire (mostly) one of the four file types mentioned above. Ultimately it will depend a little on what music player you are utilizing. If you have iTunes, whether on a Mac or PC, then the Apple-compatible formats, AIFF and ALAC will be your first choice. FLAC is not yet supported on iTunes and WAV doesn't carry meta-data. If you prefer Windows music player then FLAC in addition to MP3 and WMA.
Downloading Lossless Files
This can be a bit disappointing. There are sites such as HD Tracks which offer lossless tracks in several formats but they tend to have a limited selection and are quite expensive. For example, at the time of writing, Miles Davis' Kind of Blue in AIFF format is $24.98 from HD Tracks, $6.99 for either an MP3 download or (new) CD from Amazon, $9.99 as an AAC download from iTunes and as little as 24 cents as a used CD from Amazon. More on CDs in a second but twenty five bucks for a download of a popular album is steep.
The CD bargain
For me the absolute best way to get high quality digital files onto your hard drive is to rip (copy) them from a CD. There are several good reasons for selecting these rather out-of-fashion shiny discs instead of downloads (lossless or otherwise): (i) the CD format is lossless (ii) CDs usually contain interesting sleeve notes, lyric sheets, artist/band history, production details etc. (iii) you get a little bit of album art -not what it was in the heyday of vinyl but artwork nevertheless (iv) many recordings (usually older material) can often be found on CD but have not yet found their way to digital download sites (v) in case of catastrophic loss of your hard drive/music library you have a solid backup and (vi) they are as cheap as chips. I try to buy mine used from Amazon: often the cost of the postage exceeds the cost of the item. The only downside is that you have to wait a couple of days to get them but that seems a small price to pay for all the advantages.
Torrents and File Sharing
Look, just don't do this! First of all it's illegal and and second, you have no control over the quality. In the US more than 200,000 people have been sued for file sharing since 2010. If you can't afford to buy, too bad -it does not give you the right to steal.
Playback of your music is a little tricky as not all players are created equal. iTunes is popular as it organizes music quite comprehensively although it's a bit complex for my taste. Also it's free and can be used with Apple's "Remote" function on iPads and iPhones. The problem with iTunes it that it is aimed at the multi-media user and other players simply sound better. This in part due to the bitrate of the player -that is to say the number of pieces of information it can handle per second. Generally speaking the more the better. Bitrate is not the entire picture, however and some experimentation will be necessary. Perceived sound quality is down to many factors including hardware (especially the type of DAC but speakers, amp and interconnects also have an influence) and user preference. Some players cost quite a bit more than others and user support is variable. You'll have to experiment a bit here. Most offer a free trial period. Some have a very clean user interface and others are a (to my mind) a bit clunky. Most will utilize or integrate with your iTunes library. Sound quality does vary quite a bit although this is quite a subjective matter. Players, other than iTunes, include: Decibel, Amarra, Pure Music, Audrivana, BitPerfect and Fidelia.
This is the process of copying your music -usually from a CD. Their are proprietary apps for doing this although I find iTunes quite adequate. Specialist programs offer superior error correction that iTunes although in practice I don't find this to be much of a sonic advantage and they can be quite non-intuitive to use.
Phew! I hope that wasn't too bewildering. In the next and final part of this series I'll offer some very specific recommendations based on my own experiences.