[amaynard]

Has anyone else noticed that the sound quality from the Ipod is significantly inferior to that directly from Itunes on the Mac, or do I have a suspect specimen? I'm using a new Ipod with a standard CMOY amp and ER4-S's. The sound quality on MP3's and AAC's is OK, but rather fatiguing - I thought at first that it was just the compression, but listening to the same files in Itunes using the sme amp/phones is a revelation - the sound opens up considerably, the highs are clearer and purer, and the sound significantly less fatiguing overall.

Going back to the Ipod, it sounds as if it uses additional compression between the original file, and the output - certainly, the sound quality resembles that from a low bit rate MP3 file.

Something else I noticed while trying to identify why the Ipod sounds inferior - if you encode fairly complex sounds such as piano reverberations or strings as high bit rate MP3 files (256 kbs and above), you get a clear ringing in the tones on the Ipod - a rather nasty artefact that I think has been generally attributed to MP3 encoding. However, there is no evidence of the ringing when playing the files through Itunes - either the decoders used in Itunes/the Ipod are different, or the Ipod is doing somethung unpleasant to the signal.

Note that 128 kbs AAC files actually sound pretty good directly from the Mac.

Is this a recognized problem, and if so, is there a fix, or should I be returning the Ipod until the technology improves?

Cheers,

Andrew

 

[hempcamp]

My iPod's output is crystal clean compared to both my iBook (where the jack is right next to the spinning hard drive!) and my old Sony PCDP and CDP, but I don't own any headphones as revealing as the Etys.

When you say "significantly inferior" what do you mean? Also, which Mac are you using with iTunes? Is there a particular song at a particular bit rate that sounds especially bad?

--Chris

 

[amaynard]

I'm using an Ibook G4 Titanium - the output is a little noisy, and not the best around, but still good enough to highlight differences in playback sound quality compared to the Ipod.

The MP3 artefacts are only apparent on quiet but classical music encoded at high bitrates - quiet piano passages for instance sound like the player is underwater!

The sound quality problems with AAC files isn't quite so obvious, but does affect all music types. I haven't tried this yet (I must do so), but I would imagine that the sound quality of a 128 - 256 kbs AAC file on the Ipod sounds something like a 64 kbs or less file in Itunes. The degredation heard on the Ipod is similar to what you get with lower encoding rates - loss of detail, especially high frequency, and loss of spatial positioning.

Andrew

 

[MacDEF]

I think the problem is actually the opposite -- the iPod's output is much better than the PowerBook's, so the iPod is revealing the limitations of your MP3s/AACs. The iPod is one of the best-sounding MP3 players on the market by all accounts, and although the PowerBook headphone jacks are good for a laptop, they aren't as good as the iPod, in my experience.

 

[Geek]

This honestly doesn't make sense. I have heard two separate IPods and both had what I would call quite good reproduction of sound. Using DT250-80s straight through the headphone jack I was able to tell the difference between 128kmp3s and 192kmp3s, and the subtle difference from 192k to 256k. Honestly there may be something wrong with your compression or the files themselves. I think that the IPod has a good phone out.

Cheers,
Geek

 

[amaynard]

The effects are subtle, but definitely there - I would expect the decoding artefacts to be obvious even when using bulk standard quality headphones. The AAC playback is OK, and it is only in comparison with other decoders that I noticed the difference. There are clear artefacts on the MP3 playback - but only on quiet instrumentals with a complex frequency spectrum (e.g. piano).

From what I can tell, this is not an audio output issue, but a decoding issue.

Andrew

 

[plainsong]

Quote:

Originally posted by MacDEF I think the problem is actually the opposite -- the iPod's output is much better than the PowerBook's, so the iPod is revealing the limitations of your MP3s/AACs. The iPod is one of the best-sounding MP3 players on the market by all accounts, and although the PowerBook headphone jacks are good for a laptop, they aren't as good as the iPod, in my experience.

I'll second this. My 10gb iPod (old gen) sounds better than my iMac playing the same music, either 192k mp3's or 160k aac. I improved the iMac a bit with the Griffen iMic though - that is, I'll hear the information in the files better on the iPod, for better or worse.