[Hier]

This thread follows on from an issue I raised in another thread: Can iPod have gapless playback?.

I didn't want to get too Off Topic, so I decided to start a new thread.

The following is a summery of the issue at hand:

Me:
Quote:

I've just bought my first DAP, which is also the new iPod 20GB Colour. The first thing I did was try recording with MP3, AAC, Lossless & WAV. I'd definitely agree that AAC would be the best alternative to Lossless. I wouldn't use anything less 320 kbs (44.100KHZ) though. For what its worth I found AAC to be an acceptable compromise, if your looking for more storage capacity. Having said that, I find the AAC recordings a little airy and lacking in drive/punch. The recordings also lack the bass definition present in the lossless recordings. These comparisons were made with Senn 497's - straight out of the headphone jack. All comparisons were made with the same song: ‘The 5th Exotic’ by Quantic. Interestingly, in spite of what other head-fiers have said, I found that I could hear a difference between lossless and an uncompressed WAV. The difference is however only noticeable with particularly challenging music, so Lossless is an acceptable compromise. AAC is however a step too far in my opinion. I also auditioned the above recordings with a s/hand Super Mini Moy, which I received this morning. The differences between the MP3, AAC and WAV became even more obvious. The Lossless recording however benefited from amping, bringing the quality closer to the WAV and making Lossless my compromise of choice.

Blessingx:
Quote:

Hier, the only way lossless and uncompressed could sound different (lossless uncompressed should be bit identical to uncompressed) is if the decoder is in error. Do you think the iPods decoder has an issue?

Me:
Quote:

I tried blind testing the recordings and each time I managed to spot the WAV recording. Rhythms were more controlled and dynamic and the bass was more controlled and less woolly. I even tried a blind test with a couple of friends. One could hear a difference, the other couldn't tell the AAC, Lossless or WAV apart. Is it possible that my iPod is faulty? How would I tell?

Blessingx:
Quote:

Well if it sounded different than WAV/AIFF it would be. Now is it your iPod, all iPods, or your imagination is the question. Most are gonna say the latter (especially with 497s), but who knows. Do a test with iTunes and see if you found the same thing.

I have now tested the same song with iTunes, using my Senn 497's. I couldn't tell the difference!

This could of course mean that my PC sound card isn't up to the job.

I decided to do another test with the iPod.

This time I used the song 'I Am the Black Gold of the Sun (4 Hero Remix)' by Nuyorican Soul.

Once again listening through my Senn 497's and a Super Mini Moy amp, I thought I could hear a difference between the WAV & Lossless versions.

I tried blind testing again. This time however I failed to distinguish between recordings less than 50% of the time!

I then tried another blind test, once again using 'The 5th Exotic'. Again I only managed to distinguish recordings less than 50% of the time!

These stats would indicate a result no better than chance.

Initially I thought I could hear a difference in the very high and very low ranges of the sound spectrum, so I figured that some people just couldn't hear what I was hearing. The blind tests appear to indicate otherwise.

I even went back and compared specific sections of each song, concentrating on specific notes. Again I thought I could hear an almost unperceivable difference...................I suppose that the mind can be a powerful thing.

Was I paranoid that I was losing something in the recording?

Probably!

Any thoughts on this, or similar experiences?

 

[TheSloth]

This has been tested and retested countless times. The digital output from ALAC is proven to be bit identical to that of AIFF and WAV. Test it yourself if you like - rip a cd as an AIFF file, then convert it to lossless, and then convert the lossless file back to AIFF. Take the final AIFF file converted from the lossless, and use any audio program to invert the audio wave. Merge that wave form into the original ripped AIFF file and you'll find you're left with a beautiful straight line of nothingness. The only possible explanation for any differences perceived in playback, assuming it's not placebo, is that the the algorithm/postprocessing used for decoding them is slightly different for the 3 formats, resulting in miniscule differences in output from the internal DAC. That, however, is rather unlikely. Also, remember that the bit output from the Airport Express has also been shown to be bit identical to the original CD, and note that all audio signals transmitted to Airport Express are first compressed into ALAC by iTunes to save bandwidth.

 

[NightWoundsTime]

I've done many ABx comparisons on MP3's. For any modern produced music it's impossible to tell the difference, too many details are lost in the commercial processes. Where I can tell the difference is in classical or live recordings which may not sound "clean" but preserve detail well. On the Waking Life soundtrack I found a passage that I can identify even a 320kbps MP3 100% of the time. There's a lot of ancillary toe-tapping, clapping, coughing, and other noise from the musicians. On a few of these moments I can certainly hear the difference, although with 320kbps the difference isn't really something that bothers me. The real problem is the masking that MP3 does, which may not be immediately noticeable but still exists and will show up for brief moments. Sometimes this isn't reproduceable in testing against lossless, but I can gaurantee you it's there. I use lossless formats yes for mostly a placebo effect but why not? Hard drives are cheap, my Ipod still holds way more music than I can listen to between times at home to upload new music.

 

[Jahn]

i used to have everything in lossless until my ipod crashed for the third time and i returned a few ipods ... it wasn't worth it. I converted the whole shebang to 320AAC, got half of my storage space back, the ipod runs as smooth as silk, and my ears can't hear the difference, even out of itunes from the comp to the 0404 to the solo to the HP2.

 

[Hier]

Quote:

Originally Posted by Jahn i used to have everything in lossless until my ipod crashed for the third time and i returned a few ipods ... it wasn't worth it.

Is this a common problem with the iPod? I've only had mine for a couple of days, so its probably too early to tell if I will have any similar problems.

Quote:

Originally Posted by Jahn I converted the whole shebang to 320AAC, got half of my storage space back, the ipod runs as smooth as silk, and my ears can't hear the difference, even out of itunes from the comp to the 0404 to the solo to the HP2

It would be great if I couldn't tell the difference between 320AAC and lossless. But I can, and the difference is quite pronounced to my ears.

I suppose I will soldier on with Lossless and see what the future holds for the iPod.

 

[binkgle]

right now with my sb live! 5.1 (kx drivers) and px100 i can't tell the diff between aac160, lame -aps, and wav. that might change when i get my ms-1s and av710, but for now.......

 

[vranswer]

Quote:

Originally Posted by Hier Is this a common problem with the iPod? I've only had mine for a couple of days, so its probably too early to tell if I will have any similar problems.

For me it has been. Every iPod I've owned had issues playing lossless, skipping and such. But the biggest issue of all is battery life, which takes a serious whack with ALAC. Difference in sound just not worth it for me.

 

[rextrade]

Quote:

Originally Posted by Hier It would be great if I couldn't tell the difference between 320AAC and lossless. But I can, and the difference is quite pronounced to my ears. I suppose I will soldier on with Lossless and see what the future holds for the iPod.

Hier--have you done a blind comparison? If the difference is pronounced to your ears, you have some damn good ears.

 

[Hier]

Quote:

Originally Posted by rextrade Hier--have you done a blind comparison? If the difference is pronounced to your ears, you have some damn good ears.

After the above posts I decided to do some blind AAC/Lossless comparisons.

The result, after 10 random comparisons: I picked out the AAC every time.

I can hear notes in the highest and lowest ranges being cut-off and there is a definite lack of separation between high, mid and low ranges.

Curse these ears of mine. I wouldn't have to buy so much expensive kit if I was as cloth eared as most of the people I know.

 

[K2Grey]

10/10 between 320kbps AAC and lossless? Most impressive. Now go over to hydrogenaudio and engage in an argument over transparency of AAC

 

[Twombly]

Are you doing the ABX right? Make sure you set the number of trials beforehand.

 

[Hier]

Quote:

Originally Posted by K2Grey 10/10 between 320kbps AAC and lossless? Most impressive. Now go over to hydrogenaudio and engage in an argument over transparency of AAC

Although I have been able to identify the AAC 10/10, I suspect that the result may vary according to the song.

Busier songs with a lot going on may be harder to tell apart. Then again it might make things more obvious. I will have to see.

Quote:

Originally Posted by Twombly Are you doing the ABX right? Make sure you set the number of trials beforehand.

I wasn't sure what ABX was. I've now looked it up and understand.

I didn't use ABX, my PC just isn't up to the job as it has a lousy sound card.

The blind tests were conducted on my iPod. I used 2 different songs, with a Lossless and AAC 320 version of each. I then had a friend control the ipod so that I couldn't see which version of each song I was listening to. Each song/version was then played according to the roll of a dice.

Primative I know, but I'm satisfied that the test was both random and blind. I even decided to do a second test, however this time my friend tried something different without my knowing. The same procedure was used, but this time my friend only ever played the lossless version of song 1 and the AAC version of song 2. The results 10/10 again.

 

[Hier]

I received a cable today for connecting the iPod to my Naim Nait5 amp.

I decided to do some more tests through my amp and B&W P5 speakers.

The result: Differences between the AAC 320 and Lossless were even more dramatic.

Before buying the iPod I had always intended using it with my home hi-fi and the hi-fi set up at the family home. It looks like Lossless is the only compressed format that will satisfy this kind of use.

 

[Oink1]

Do you have an 'all Naim' rig David?

 

[Hier]

Naim Nait 5 amp (+ Naim Stageline), B&W P5 Speakers (+ Nac A5 cable), Marantz DR6000 CD Recorder, Linn LP12 Turntable (Ittok IV II arm + Goldring 1022GX Cartridge). Saving up for a Naim CD5X & possibly a Naim power amp to pair up with the Nait 5. I should add all of this to my non-existent sig.

I suppose you could say I'm a bit of a Naim convert.

(Paul, Thanks for the cable by the way.)