mp3

 MP3 is, by its very nature, lossy - I'm not sure whether you're after players or files, so I'll try to cover both.

Apple iPod players will support Apple Lossless audio, but this isn't MP3 - you see what happens when a term like MP3, Hoover or Sellotape becomes a generic term? The terms iPod and MP3 seem to have become interchangeable.

There's also a lossless form of Windows Media Audio (WMA), but this isn't supported by too many players, and FLAC (Free Lossless Audio Codec), which is an open-source format. FLAC reduces the file-size by about a half, but doesn't lose any bits in the process. But again, it's not supported by all players.

If you're talking about finding files, some hunting will be involved. But Linn Records, for example, makes some of its titles available as FLAC downloads - see here.

Andrew's spot-on.

We did test all the various formats for a 'What MP3?' special, and Apple Lossless was the best-sounding of the bunch - though even at its best, it didn't match uncompressed (PCM) CD audio.

It enrages me that so many MP3 and even Apple AAC downloads are described as 'CD quality' when they are far from it. Even the DRM-free new iTunes downloads only have a 256kbps bitrate (standard iTunes downloads are a mere 128kbps).

Unless it's for a Shuffle or smaller nano, we'd strongly recommend ripping your own tracks at a minimum of 320kbps. That and a decent pair of headphones and you'll hear so much more from your portable/streamable tracks.

yes it was the files I was enquiring about for the 80 gig ipod

thank you both for your help 

I didn't see that issue. Out of interest, was FLAC tested as well? A month or so ago when I got my Sonos, I had to choose whether to re rip my CDs in either FLAC or Apple Lossless and went for FLAC in the end. It sounds fine to me but now I think I might be missing out

Thanks,
James

This is incorrect.

Apple Lossless and FLAC are the audio equivalent of a Zip file.  They don't lose any data, but merely pack it more efficiently.  When 'unzipped' back to the original PCM format, an Apple Lossless file will be a bit-for-bit perfect copy of the data off of the CD.

If you heard a difference between the two, you either imagined it, or it was just an artefact of using different replay equipment.
 

hi James,

We didn't test FLAC in that particular test (it wasn't as widespread then), but I have heard files in both, and i'd say they're broadly compatible. If you're happy with it, stick with it!

However, FLAC is not compatibile with iTunes, so if you were planning to port your music collection to an iPod, you won't have much luck....

Sorry to contradict you, CS, but there was a definite - if minor difference - when you compare the original CD file to the Apple Lossless file on exactly the same equipment. Any form of conversion or manipulation can and does effect sound quality - which is why cables and connections are so important in the hi-fi world. Yes, even in the digital domain.

Try this simple test :-

1. Import a CD into iTunes using AIFF or WAV format (ie. the original CD PCM format).

2. Within iTunes, convert the above file to Apple Lossless.

Now try playing both files through the same DAC/amp/speakers of your choice.  You will not discern any difference, because there is no difference.  As I said, an Apple Lossless file does not change the data at all, once played back in PCM format.

Note:- Make sure you have all the optional 'sound enhancements' in iTunes switched off, as some are 'on' by default. 

cs,

Your point that a 'lossless' format packages the information differently but does not 'lose' any (as opposed to lossy codecs that dispense with data) is of course true. However, the point Clare is correctly making is that our reviewers have shown time and time again that ANY difference in processing or components can have an impact, however small, on sound quality.

While the Apple Lossless codec is, like FLAC, extremely efficient at rendering the original data (and to be fair, we recommended using lossless in our feature on the subject), it is still the case that our reviewers, myself included, perceived there to be a tiny difference in quality - in blind tests.

The uncompressed file of Regina Spektor's Fidelity on my laptop is a file of 38.3MB, with a bitrate of 1411 kbps. The Apple Lossless file of the same song is a file of exactly 24MB, with a bitrate of 881 kbps.

Yes, the lossless codec tries - and largely succeeds- to reconstitute all the original data. But this still involves a DIFFERENT coding and processing of the data, which to our ears has a small impact on quality.

All of that said, we HIGHLY recommend using lossless codecs for audio in hard drive or 'MP3'-based listening.

As part of my job (professional electronics engineer), I have access to software (Agilent SystemVue) which allows the comparison of such files, on a sample-by-sample basis.

I can verify that the test I have described yields identical sample values - that is, you can overlay and subtract the two waveforms to give a zero output.  The packing, formatting and unpacking has had no effect on the PCM sample values.

If you have heard differences, it must be some other effect - most probably a slight difference in volume, where one file has been (maybe inadvertantly) scaled slightly relative to the other, which would introduce a difference in the quantising and hence audibility.
 

In the world of hi-fi and home cinema, there are many arguments, such as yours, which suggest this or that variable 'makes no difference to sound quality'.

As full-time professional reviewers, it is our view, based on much experience, that the alteration of almost any variable will have some effect, however small, on sonic performance. It should always be borne in mind that the 'data' in music consists of information of such astounding subtlety, that any difference in processing or setup - from the lengthening of a cable, to the distance between components, to an extra stage of digital processing - can indeed make a difference.

I'm sure the measurements you've taken show identical data streams. I'm equally sure - because it happened in front of my own eyes - that when I blind tested one of the most experienced hi-fi reviewers in the country with five different versions of two very different pieces of music (the 'versions' went from MP3 128 kbps up to uncompressed, and included Apple Lossless in each case), he rated them for sound with 100% consistency - with the uncompressed file scoring highest and the Apple Lossless file coming (a very close) second. Make of that what you will.

As I said, you must have inadvertantly made some other change to the file, which is not part of the lossless encoding process.  Carefully check all your iTunes settings.

Lossless codecs, such as ALAC, FLAC, etc, are totally deterministic and reversible algorithms.  So, if you take a 16 bit, 44kHz sample stream, convert to ALAC, then convert back again, the resultant sample stream will be identical to the original.  There is absolutely no change or errors introduced by this process.  You end up with the same file as you started with.  Try it for yourself, and look at the files.

It's no different to zipping a Word doc, then unzipping it.  You get back what you started with, error free.

Remember that effects such as distortion and jitter are only manifest during the D to A process.  If you feed the same file into a DAC, you get the same audio output.  Is that so difficult to understand ?

Blind tests mean nothing. Only properly analysed double-blind tests have any validity. There are many subtle signals that you can accidentally give away to the reviewer, however well intentioned you are.

You will know from the "wma lossless to iPod" thread that my views on Lossless are the same as cs's. So, I have a challenge for you:

You pick any track you like, rip it from CD in AIFF or WAV format, and take a 3 minute section from it (if the track is longer than 3 minutes). You then send me the file. I'll get my girlfriend to duplicate the file 9 times, and then convert the 10 files to Apple Lossless and back to AIFF/WAV (giving 20 files total - 10 original, and 10 converted to Apple Lossless and back again). She'll then randomly name all files one to twenty, keeping track of which are "original" and which have been converted to Apple Lossless and back again. She then gives the files to me on data CD to check their integrity. I then send the CD to you, and you have to determine which 10 files have been converted to Apple Lossless and back. You can ask as many people as you wish to help. The probability that you'd get it right by just randomly guessing would be 1 in 184,756. Let me know if you're up for it...

Hi, Mr. H. What happened with the result of the experiment?

Hi everyone,

This is a very interesting debate not least because it is heretical to hifi buffs.  I suggest that some of the questions that the debate highlights include:

1.  Can anyone really hear any difference in a 'real' environment between these formats? 

2.  Alternatively, can anyone who is not a trained and experienced sound engineer/reviewer (much like a 'sniffer' trained to appraise perfumes or wine') really hear any difference?  e.g. Computers that claim to show Xbillion collours when the human eye can only detect X divided by 10 colours.

3.  Even if there is a difference if that difference is negligable or at least marginal, is it worth the extra cost for that difference? 

For what it's worth I agree with everything that cs and Mr H have commented.  I have an interest in psychology and alternative medicine and it is uncontroversial to state that unless the test is double blind it is pretty worthlesss.  I like the idea of Mr 's test but wonder if WHFM will take the challenge as a 'wrong' result could bring down the house of cards!

Now I'm not saying that there's no validity in reviews because I certainly value reviewer's advice and opinion on how speakers and receivers etc sound and, clearly, a great pair of speakers is going to sound far better than a smaller/cheaper pair.  I just have doubts that most people (if any) can really hear any difference in most pop/rock recordings whether at 128kb or 1441kb.  Maybe my system isn't good enough to discern the difference (or more likely I'm going deaf in my old age!).  I have an MT30 home cinema coupled to a Denon A1XVA connected to an Onkyo SR875.  Maybe the Denon is working hard to make the most of the mp3? 

What do others think?  Shall we bring it on and maybe save ourselves thousands of £££ in future?!!?

:)  Ian