Golden ears of the world, unite! While other people are happy with the incredible convenience that listening to MP3s and AACs on an iOS device offers—thousands of songs, anytime, anywhere—audiophiles decry the lower quality that comes as part of the bargain.
If you crave sound quality on a par with (or even better than) a CD but still require the freedom that comes from carrying a bunch of music on your iPhone or iPad, it's time to look at lossless audio.
A quick compression primer: Lossy compression formats such as AAC and MP3 take up less storage space than standard CD audio does, but if you listen carefully you might notice that something is lost in translation. It's usually the low-end and high-end frequencies that are sacrificed in the name of smaller file size.
You could opt for uncompressed audio—AIFF or WAV files that are an exact copy of the song on a CD—but the files become so large (about 10MB per minute) that they make storage space a real concern.
That's where lossless compression comes in. Lossless formats such as Apple Lossless Audio Codec (ALAC) and Free Lossless Audio Codec (FLAC) are still larger than MP3 and AAC formats, but they tilt the quality/size balance in favor of sound quality. In lossless compression, the codecs use algorithms that shrink the file size but allow the original to be reconstructed exactly. You end up with no quality loss, and lossless files are 40 percent to 60 percent the size of uncompressed CD files (still a fair bit larger than lossy MP3 or AAC files, though).
How to listen to lossless audio on iOS
Listening to lossless files on an iOS device can be seamless or may require a bit more effort, depending on your choice of lossless format.
Apple's Music app for iOS natively supports the company's own ALAC format. To listen to ALAC files, just transfer them to your iOS device via iTunes, as you would with files downloaded from the iTunes Store or other music you've ripped to your computer. The files appear in the Music app with the rest of the music on your device.
If you prefer FLAC—a common format for live and classical music downloads—you'll need to download an app such as the free VLC 2.1 for iOS or Dan Leehr's $10 iOS 7only FLAC Player. Onkyo also recently released HF Player, a free EQ app that includes a $10 in-app purchase to enable FLAC and other high-resolution audio-file playback.
With any of these apps, you'll need to manually transfer the files to your iOS device. Connect the device to your Mac, launch iTunes, and select the device in iTunes's source list on the left. Click the Apps tab and scroll down to the File Sharing section. Click the app you want to use, and drag your music files into the documents list to the right (or click the Add button to choose the files via the Finder). Your files will transfer immediately, and you should be able to play them through your selected app on your iOS device. (They won't appear in the standard Music app.) Alternatively, you can stash files in Dropbox and then choose to open them in an app such as VLC, although you have to download and open each track individually.
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