If you recently looked at a new head unit for your car it may have mentioned the WMA, MP3, AAC, and/or WAV audio file formats as they are some of the most common in audio electronic devices. You likely understand them on the surface but beyond that what does one audio format have over the others and how does it affect the quality of the sound?
File Size
The larger the file the more space the file needs on your storage devices and so many formats take advantage of compression. This allows the same music to be saved as smaller files.
The Waveform Audio File (WAV) format is well-known for its standard uncompressed audio format used by Microsoft (its Mac OS equivalent is AIFF ). This file is bigger than the lossless compressed WMA and lossy compressed MP3 and AAC formats. In some cases as much as 12 times the size.
Quality of Audio and Compression
As just mentioned there are two types of compressed data, lossless and lossy. Lossless means, in theory, the compressed data retains the same quality of sound as the uncompressed version. Lossy “loses” some of its pieces, those mostly inaudible to humans, to allow a higher rate of compression.
Many quality after market and many of the more recent factory car stereos will play some or all of these audio formats. One such car stereo is the Clarion CZ500.
WMA – Created by Microsoft uses a lossy compression, though the release of more recent WMA formats has included a lossless as well (WMA Lossless). Advanced Audio Coding format (AAC) are lossy compression audio files.
MP3 – The MPEG-2 Audio Layer III format, lossy compression, has become very popular and is pretty much the standard for most software and hardware companies. Using various bit rates, amount of data to be used per second, the user can select his prefered level of compression, auidio quality audio (higher bit rates), and compressed file size.
AAC – A relatively recent format, is not as well-known but provides a better quality at similar bit rate compared to an MP3 file. The difference is more significant at the lower bit rates. This format is the a standard for Apple.
The WMA formats are, for the most part, the competitor to the MP3 format. There is still, of course, debate among audiophiles as to which is truly superior but for most of us either will work at the higher bit rates. As compressed files go, both of these formats are quite common and playable in most programs and audio hardware.
AAC is the growing format for compressed high quality audio files. This is most likely because of its connection to Apple. Over time you will most likely have audio diles in all of these formats so keep this in mind when selecting you car stereo.