Autechre “Move Of Ten”

As has been their wont, Warp released the download version of Autechre’s new album Move of Ten as a digital download in advance of the physical product. So I bought it yesterday.

I got the 24-bit WAV file version because, well, I have the hardware to play it and it was only a dollar more. I’ve spent a little time comparing the 320kbs MP3 file and 24-bit WAV files and it’s intriguing. I honestly can’t hear the difference — but then I only have a $500 playback system and nearly 53-year-old ears.

I messed about a bit with the track Rev(1) comparing the 2 files audibly, and then figured screw it — let’s get scientific. I loaded both the WAV and MP3 files and mixed the inverse of one with the other, trying to get as close as I could to do it 100% in phase. Then I normalized it.

This is the result:

The apparent difference between the WAV and MP3 is some white noise with a pretty wide stereo field. Interestingly, it’s not clear to me whether that’s what’s missing in the MP3, or what was added to the MP3. I suspect they added additional mastering processing to the MP3 to try and match the WAV and MP3 by ear.

If that’s the case, then the residual difference between the two could be the application of a digital exciter process, whose job is to subtly distort the signal to make it sound brighter and more ‘in focus.’

The Album itself is pretty ace, too, audio geeking aside.

8 Replies to “Autechre “Move Of Ten””

  1. Geekery aside – which is cool – I find it’s the first album of theirs in a while that I have repeatedly been going back to again and again (sure it’s only been out for a week). It’s pretty damn cool and very minimal at the same time. I’m amazed by what I keep hearing come out of it.

    If i were ever to meet them I want to ask the “Delay vs. Reverb and why?”

  2. I bought the 16-bit WAVs, then converted them to ALAC (basically iFLAC) as I figured that my usual listening environments weren’t going to reveal anything with the 24-bit files. Like the album quite a bit — they’re on a roll.

  3. Interesting experiment. I’m puzzled though…Why wouldn’t the resulting ‘noise’ be the compression artifacts of the mp3?

    1. @mark: To some extent you’re right, they’re ‘artifacts of compression.’ But one shouldn’t over-simplify. Any difference between the encoded and un-encoded audio is by definition an artifact.

      But the way MP3 encoding works is to eliminate sounds that will be masked by other, louder sounds at similar frequencies. This is a psycho-acoustic phenomenon called ‘masking.’ So my experiment — summing the inverted WAV file with the MP3 file — should theoretically make audible what is different between the WAV & MP3

      As I pointed out, they might have remastered the uncompressed WAV files to try and minimize the undesirable effects of MP3 compression, in which case the two versions of the same audio file will differ in ways not explained simply by MP3 artifacts.

      I suspect that is is the case, because the ‘difference’ audio is louder than I would have expected from the residual MP3 artifacts.

      1. Fascinating. I had no idea that WAVs can be adjusted to pre-empt the effects of MP3 compression. Thanks for the explanation.

  4. How big are the 24bit wav files? I bet they’re huge, eh? Also, do you know if they can be compressed with FLAC?

  5. when you talk about white noise, the first thing I think about is dither, which could definitely be used to counteract aliasing in MP3s, as it’s been used to mask similar aliasing in 16-bit recordings. 24-bit audio probably negates the need for dither.

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