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Speculation On a Lossless iTunes Store

Posted by kdawson on from the filling-up-the-160-gb-ipod dept.

DrJenny writes "C|net UK has up an interesting blog post predicting that within 12 months Apple's iTunes Store will include a download center for lossless audio. This would be a massively positive move for people who spend thousands of dollars on hi-fi gear, but refuse to give money to stores that only offer compressed music — they could finally take advantage of legal digital downloads. The article goes into details on how Apple's home-grown ALAC lossless encoding relates to FLAC, DRM, and the iPod ecosystem."

1 of 321 comments (clear)

  1. sampling frequency and signal frequency !mix-up by Animaether · · Score: 1, Troll

    I'm completely with you on the "nobody but the freakier people are going to notice", and they'll probably have gold-plated, gold-cable, etc. SACD players. Or, if they're really serious, they do away with the gold plating and have a goldsmith permanently goldsolder the wires right onto the board.

    That said... the sampling frequency shouldn't be mixed with the signal frequency in the way you mention; e.g. 44.1KHz, divide by 2 (yay Nyquist), ~22KHz is the maximum frequency you can sample. ergo: 96KHz allows you to sample 48KHz signals and nobody can hear 48KHz anyway so what's the point.
    Ah, true, but...
    A 400Hz sine wave is now -also- sampled at the 96KHz level. Suddenly, that sine wave is looking twice as smooth.

    Think of it like computer graphics. If you have a 320x240 15" display (12" by 9", non-widescreen 4:3), your pixel is going to be nearly 1mm on each side (12*25.4 / 320). A 1600x1200 display will have a pixel that is going to be much smaller, about 1/5th of a mm on each side (12*25.4 / 1600). Now you might not often find any reason to display a dot that is 1/5th of a millimeter at each side. However, if you were to display a large circle on the 320x240 display, it will be blocky. Do so on the 1600x1200 display, and it will appear to be much smoother.

    Alternatively, find a piece of music that doesn't seem to do much over 22KHz, and band-limit it so that everything over 22KHz gets cut off anyway. Save this for later playback. Now actually downsample that to 22KHz. Now play back both files; see if you can tell the difference. Again, any high tones over 22KHz are gone anyway, so all you're hearing is the loss in fidelity of the lower-frequency ( 22KHz) signal.