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Subject: Re: Rockbox sound quality

Re: Rockbox sound quality

From: Antony Stone <>
Date: Thu, 11 Sep 2008 21:12:41 +0100

On Thursday 11 September 2008 20:43, Douglas Anthony Cooper wrote:

> Another interesting point: I get *superb* sound quality via the
> headphone jack of the iPod 5G when I boot into Rockbox. The iPod's
> native OS sounds considerably worse: less clarity; narrow soundstage,
> etc. An article I just read

Where, please?

> suggested this shouldn't be the case:
> graphed outputs from both systems are identical.

What are the "graphs"? If you mean analogue sound waveform output, then
identical means identical. If you mean spectrum-analyser-type frequency vs.
amplitude charts (sometimes likened to graphic equaliser settings) then this
can mean anything, really.

> So what's going on here? These are mostly AAC files at 160 kbps, and MP3's
> at approx. 192 (VBR). I'm pretty sure it's not the placebo effect -- the
> difference is pretty obvious.

There's no reason why two different codecs (in this case, the "dec" part)
can't produce noticeably different results from the same input (I assume you
*are* playing the exact same files when comparing the two systems, yes?)

Remember that lossy encoding such as MP3 is designed to reproduce what the
human ear/brain combination hears, not to reproduce the exact same waveform.

I'm not familiar with the original firmware on the iPod 5G - can you play a
lossless (eg: WAV) file and see (hear?) if you notice any difference between
the two, thereby identifying whether it's the codec algorithm which is
causing the distinction?


"The future is already here.   It's just not evenly distributed yet."
 - William Gibson
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Received on 2008-09-11

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