An Introduction to digital audio
Start here for everything Home Audio.
Audio File Formats The way you store you songs (data files) can drastically affect the quality of audio playback. While of a less concern the file type affect how much disk space is required. Audio file formats can be divided into four categories, from best to worst:
1. High Resolution Audio HRA
2. Uncompressed
3. Lossless Compression
4. Lossy compression
There are many formats available. I will focus on the main formats in each category. High Resolution Audio HRA can be broken into two categories PCM based with sample rates and word lengths greater that CD’s 44.1 kHz/16-bit and Sony’s Direct Stream Digital (DSD.) DSD files can be DSD-64 or DSD-128
Uncompressed Audio Format
● WAV Waveform Audio File
● AIFF Audio Interchange File Formatted – developed by Apple
Lossless
● FLAC – Free Lossless Audio Codec
● ALAC – Apple Lossless Codec. File extension .aif or .aiff
● WMA-losses – developed by Microsoft
Lossy
● MP3
● AAC3
● WMA3
● MP4 - MPEG-4 Part 14 or MP4 is a digital multimedia format most commonly used to store video and audio. The only official filename extension for MPEG-4 Part 14 files is .mp4, but many have other extensions, most commonly .m4a and .m4p. M4A (audio only) is often compressed using AAC encoding (lossy), but can also be in Apple Lossless format. M4P is a protected format which employs DRM technology to restrict copying.3
Music Management Software: Mac Based
● iTunes
● Amarra
● Audrivana
● Channel D Pure Music
PC Based
● J River: Media Center
● Foobar 2000
Ways to Acquire Music ● Physical Media: CD or SACD; Blu-ray
● Download: either HRA or lossy
● Stream: lossy compression only
High Resolution Download sites
● 2L
● Blue Coast Records
● Channel Classics Records
● Cybel Records
● Download Now!
● HDTracks.com
● HighResAudio
● iTrax
● NativeDSD
● Premonition Records
● Prostudio Masters
● SuperHirez.com (from Acoustic Sounds)
Sonos Supports the following files
● MP3 (compressed)
● WMA (compressed)
● AAC+(compressed)
● Ogg Vorbis
● Audible (format 4)
● Apple Lossless ALAC
● Flac (lossless)
● WAV (uncompressed)
● AIFF (uncompressed)
● Amazon Cloud
Ripping If you have a collection of CDs that you want to convert to a digital form I highly recommend TerraSan.com. Please see their website for details. Summary Since many people are familiar with and use iTunes as the music management software and Sonos is the leader in multi-room distributed audio. I recommend using ALAC since it can be played by both Apple’s iTunes and Sonos. This gives you excellent playback quality while reducing disk space by 40 – 50%. Please note for your portable devices that you sync with iTunes you can have iTunes down-res (convert) the file so it can all fit on your portable device.
For additional resources, please visit our page on Home Audio with articles like this on everything you need to know about speakers and surround sound. Additionally, you can check out our photo gallery on the same page to explore our previous work.
Bravo AV is proud to be an HTA (Home Technology Association) Certified Installation Firm and professional A/V experts. Tom Curnin, the owner of Bravo AV, is a CEDIA Professional Designer, a certified THX Level 1 home theater professional and a member of the Home Acoustic Alliance trained to Level II. You can contact Tom directly at (908) 953-0555 or through email at Tom@BravoAV.com.