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iTunes Match (how good is 256Kbps AAC? - Page 2

post #16 of 36
Quote:
Originally Posted by Skidood View Post

Aaahh...nice catch.....it was actually 16,667 bytes per second.  Using 1024 to divide makes it 16.28 KBps.

 

What can I take from this info relating to quality of the files being streamed?  I guess it would depend on which compression format they use....

 

The sound is definitely better listening online vs. using the satelite radio.



Well with XM satellite radio I can hear a ton of compression artifacts even in my dad's Bose car stereo, I shudder to think of what it'd sound like with a nice pair of headphones or a nice speaker monitor setup...Bose setups tend to gloss over detail like that, so being able to hear it so clearly would mean it's pretty bad.

 

I haven't listened to any XM online radio streams though...but 64kbps is right at the edge of what is even remotely acceptable, doubling that to 128kbps actually would make a huge difference.

 

But keep in mind they're using AAC-HE, not just normal AAC so it will sound better than any other format encoded at 128Kbps.

post #17 of 36

oh in case some people didn't know the kbps is the combined bit rate. So if your song had two channels(stereo) and was 128kbps it was 64kbps per channel. 320kbps is actually 160kbps per ear. This is a new audiophile thread so i thought i'd just point that out so that your math won't get messed up or anything.

post #18 of 36
Quote:
Originally Posted by DaBomb77766 View Post



Well with XM satellite radio I can hear a ton of compression artifacts even in my dad's Bose car stereo,


I stopped reading there. lol, jk. =)

post #19 of 36


 

Quote:
Originally Posted by skamp View Post

That article is highly misleading. You don't listen to a perceptual codec by looking at graphs. The differences are in the vast majority of cases not audible. Aside from maybe some very specific "killer" samples, AAC ~256 kbps VBR will be transparent, i.e. audibly undistinguishable from the CD.
The whole point of a perceptual codec is to fool your ears, not your eyes.


Maybe to your ears, but I went through this whole exercise of comparing lossy vs lossless years ago and found to my ears anything not lossless was indeed audibly different and not preferred.  While you may find a lot of folks that agree with you, there are a lot that do not.  

 

cheers

 

EDIT- And agree Satellite radio bl..s


Edited by bixby - 3/18/12 at 1:24pm
post #20 of 36
Quote:
Originally Posted by bixby View Post


 



Maybe to your ears, but I went through this whole exercise of comparing lossy vs lossless years ago and found to my ears anything not lossless was indeed audibly different and not preferred.  While you may find a lot of folks that agree with you, there are a lot that do not.  

 

cheers

 

EDIT- And agree Satellite radio bl..s

^ I would suggest a blind foobar ABX right now in this day and age.
 

 

post #21 of 36
Quote:
Originally Posted by bixby View Post

Maybe to your ears, but I went through this whole exercise of comparing lossy vs lossless years ago and found to my ears anything not lossless was indeed audibly different and not preferred.

Were the comparisons sighted?
post #22 of 36
Quote:
Originally Posted by skamp View Post


Were the comparisons sighted?


sighted? what's that?

 

 

i still call for a present day blind foobar ABX with at least 16 results. and two trials, one where he uses tracks and a song he chose. and one where we do.

 

Tracks must be CD ripped with EAX to ensure validity into a .wav format. of which must be correctly encoded from that original wav into two files. one lossy file size and format of choosing. i say MP3 320kbps CBR and one that is Apple Lossless Audio Codec or Free Lossless Audio Codec.  This must also be done correctly. of which the files are inputed into foobar with the ABX add on and ABX'd with results being hidden. and then after 16+ tries, the test stopped and posted.

 

anybody is free to try this. most can't hear the difference, even worse the older you are. We are not in sound Science where most tests go, but these tests will show most people if they can or can not hear and thus make them more comfortable in using correctly self ripped or itunes bought 256kbps AAC and above tracks. (i haven't boughten off Amazon so i can't compare their tracks) illegal downloaded 320kbps do not sound the same as self ripped one's BTW.(most don't) 


Edited by bowei006 - 3/18/12 at 1:39pm
post #23 of 36
Quote:
Originally Posted by bowei006 View Post

sighted? what's that?

As in, not double blind, as in, he could see what he was comparing.

Quote:
Originally Posted by bowei006 View Post

i still call for a present day blind foobar ABX with at least 16 results. and two trials, one where he uses tracks and a song he chose. and one where we do.

Tracks must be CD ripped with EAX to ensure validity into a .wav format. of which must be correctly encoded from that original wav into two files. one lossy file size and format of choosing. i say MP3 320kbps CBR and one that is Apple Lossless Audio Codec or Free Lossless Audio Codec.

You mean EAC. Doesn't really matter.

I'd go for iTunes Plus (AAC ~256kbps VBR) since that's what we're talking about here.
post #24 of 36
Quote:
Originally Posted by bixby View Post

While you may find a lot of folks that agree with you, there are a lot that do not.

Those who agree with me usually submitted to ABX tests (or read the results of others), while those who disagree didn't (which I assume is your case).
post #25 of 36
I use itunes to rip bc like you say, very rarely will something happen and itunes has verification. Its just that to make absolutley sure i just say that
post #26 of 36
Thread Starter 
Quote:
Originally Posted by GloryUprising View Post


I stopped reading there. lol, jk. =)



Agreed, sat radio sound quality is pretty horrific, and sometimes you really hear it ( especially during one point in Deep Purple's Woman From Tokyo..I cringe everytime I hear it).  It actually seems like some audio frequencies and/or harmonics in the source material make the artifacts multiply during short periods.

Their online streaming is noticeably better.  But I do like the product (almost zero commercials, lots of variety)  I HATE commercials.


Edited by Skidood - 3/19/12 at 4:04pm
post #27 of 36
Quote:
Originally Posted by bowei006 View Post

oh in case some people didn't know the kbps is the combined bit rate. So if your song had two channels(stereo) and was 128kbps it was 64kbps per channel. 320kbps is actually 160kbps per ear. This is a new audiophile thread so i thought i'd just point that out so that your math won't get messed up or anything.



Well that's not entirely true, all modern codecs use "joint stereo" which combines some parts of both channels that are exactly the same.  So in reality a bit more bandwidth is dedicated to each channel.

post #28 of 36

Just curious are the Matched AAC files iTunes delivers for their matching service encoded from CD or from studio masters (which are much higher fidelity then CD) ?  

 

I guess I am wondering if even at 256kbps AAC they may be of better sound quality then the CD straight ?

 

Is there any online reference that discusses the process Apple uses to create their music files from the studios?

post #29 of 36

While iTunes does sell 24bit audio (anything that's Mastered for iTunes) iTunes Match will not give it to you.

 

Here's a comment from another forum

 

 

 

Quote:
I tried it with one track, and they did not match with the Mastered for iTunes version. 
  • I ripped in a track from a Diana Krall CD.
  • I uploaded and it matched on another of my machines.
  • I checked out the ripped file and the matched file in Audacity and saw they were very similar.
  • I purchased the Mastered for iTunes track.
  • Checked it in Audacity. It is clearly a different master, with more dynamic range and a slight rolloff in the upper frequencies.

So, at least for that track, there was a completely different "match" file from the Mastered for iTunes file.
post #30 of 36

Just as a rebuttal to those who say that only a "Golden Ear" can tell 256K AAC from Lossless, I want to say that I am an old man who definitely does not have golden ears, but I can hear the difference under ideal conditions:

 

1. A well-recorded song that I am very familiar with ("So What" from Ministry)

2. A long sample (at least a minute)

3. An excellent playback system (Macbook Pro, AudioQuest Dragonfly, AKG K701's)

4. A quiet room

5. The volume turned up loud enough to leave my ears ringing.

6. Lots of practice.

 

Under these conditions, using the ABXTest software, I can distinguish AAC from Lossless 60 to 80% of the time.

Definitely extreme conditions, and definitely not a perfect performance.

If I change these conditions (shorter sample, lesser headphones, lower volume, unfamiliar piece of music) I cannot tell the difference at all.

But when the conditions are perfect, the difference is audible to me.

 

Otaku


Edited by otaku313 - 6/24/13 at 10:40am
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