iPod sound quality and AAC encoding tests | iLounge News

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iPod sound quality and AAC encoding tests

iLounge reader, Marc Heijligers has posted the results of his encoding tests for AAC using iTunes and QuickTime. You’ll also find reviews of several headphones and a comparison of the iPod’s sound quality to other audio digital devices.

“Although the AAC 224bit/sec shows some artifact, you have to compare it with the original and critical source material in order to recognize those artifacts. The AAC 320 kbit/sec encoding results in much larger files, for just a little bit more quality, which was my reason not to select it. For less critical material, I use the 192kbit/sec AAC encoding, just to save some space on my iPod.”

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Comments

1

again this is only an opinion, i have totally differenet views on this subject and i think this guy is very very harsh on mp3 and really buys what apple says, even though AAC is probably better its very unfair the way he dismisses mp3. 224 - 320kbps mp3 is indistinguishable from the original if you encode well with lame settings, and 160 - 192 kbps is definately acceptable for listening, AAC does well at lower bitrates but past 192 mp3 does just as well if not better

Posted by ti on July 29, 2003 at 11:33 AM (CDT)

2

funny isnt it?

VBR has been proven by hours of testing to be of higher quality than CBR.

ABR is even higher quality than CBR. He’s eating up the media hype with AAC and running with it. The format is absolutely useless for Windows users. 50% of the iPod market are Windows users.

Posted by foo_foo on July 29, 2003 at 11:41 AM (CDT)

3

His headphone review was wack.

Sony D66SL are probably the best headphones for portable device available right now. He didnt even shed light on them.

Unrealiable review imo.

Posted by Dude! on July 29, 2003 at 11:47 AM (CDT)

4

AAC never really was a good compression format anyway, and it was Apple that decided to hype it up, saying that it “rivaled CD quality” when clearly, it was nowhere close to CD quality sound.

MP3PRO can easily beat both the propietary formats AAC and WMA at the same bitrates hands down, and Ogg Vorbis has usually come out on top of both Apple’s and Microsoft’s format in most listening tests.

This just goes to prove that AAC and WMA really offer no advantages to the user, and were probably developed quickily with little intensive research into the field.

Posted by Sraphim on July 29, 2003 at 12:01 PM (CDT)

5

once AAC+SBR is standardized it will blow everything out of the water…..using nero’s HE-AAC codec im able to get near cd quality with about 80bits/s bitrate….. it uses the same technology as MP3Pro.

Posted by lilmoonee on July 29, 2003 at 12:33 PM (CDT)

6

Not necessarily. There will still be other technologies out there. For example, most people would agree in a listening test that Microsoft’s WMA format is much worse than RealPlayer, MP3, and even standard AAC. However, people will keep using it, due to the fact that M$ still has a de facto monopoly on the desktop computer operating system industry, which most estimates put at about 93%-95% of all personal computers.

Just like how IE was a much inferior browser to Netscape in the early days, and yet, people still used IE more because it came with their computer, WMA is an inferior technology, but it will be used regardless because of the simple fact that without even a single download, all new Windows computers have an encoder built into the system default media player: Windows Media Player. No matter how good they get AAC or MP3, WMA will never be “blown out of the water”.

Posted by Sraphim on July 29, 2003 at 1:35 PM (CDT)

7

Most of this website is opinion, which is fine.  One item that he proved mathematically is that, when encoding a CD with AAC, there is ABSOLUTELY NO DIFFERENCE between the Better and Best encoding levels.  While I had heard this in the past, he proved it.

Posted by thenightfly42 on July 29, 2003 at 1:55 PM (CDT)

8

Sraphim….how do u figure that ppl still use WMA out of choice?  I mean for music stores the HAVE to because MP3 doesnt include DRM.  they dont use AAC because it isnt widely used (yet).  WMA is the only thing that is even close to protect their copyrights and have some sort of compatibility.

Posted by lilmoonee on July 29, 2003 at 2:30 PM (CDT)

9

Just some justifications.

VBR is better than CBR for a given encoding, but if the encoding changes as well, it’s comparing Apples:-) and pears, so how can you generalize about VBR and CBR??? 

I can blindly distinguish AAC 320 from AIFF, as well as MP3 320 from AIFF, as well as AAC 320 from MP3 320. Compared to AAC, MP3 has a haze over its sound, which can be easily detected if using proper equipment.

I’m pretty clear about the specific encoder I’ve used in my experiments (Quicktime), and the conclusions are logically restricted to that. I haven’t tried out other encoders that might be better than the one I’ve tried. I might do it in the near future. I’m open for suggestions.

The opinios are mine, not Apple’s. I don’t care what Apple thinks about AAC or MP3, I just observe that I agree with them on the issue of sound quality. I disagree with the 128kbit/sec standard in their music store. I disagree with the EU volume limitation, I disagree with their silent and therefore unfriendly behaviour if you report a problem to them.

I don’t have access to any headphone out there, and have a limited budget. Could you give me a link to your D66SL headphone on e.g. audioreview . People discuss hundreds of headphones on that site, so it must be there as well. I’m very curious what they say about it.

A review is an opinion by definition, hence it’s personal, as I clearly state on the site a couple of times. That doesn’t make it less reliable than any other review about whatever device under test. At least I try to show all settings of my experiment, and suggest people to try it out themselves as well. I would love their opinion, but only can put their observations in context if their experiments are well-described.

Posted by Marc Heijligers on July 29, 2003 at 3:34 PM (CDT)

10

which mp3 encoder did you use?

Posted by ti on July 29, 2003 at 3:42 PM (CDT)

11

index.html:
First of all, I investigated the differences between encoding settings provided by Quicktime Pro 6.3 and iTunes. Secondly, I listened to audible differences between encoding settings provided by iTunes and QuickTime.

encodingsettings.html:
iTunes 4.0.1 uses Quicktime for performing AAC encoding. Quicktime Pro 6.3 users ...                           

encodingobservations.html:
I’ve converted all these tracks to the following formats, using iTunes and Quicktime

Posted by Marc Heijligers on July 29, 2003 at 4:00 PM (CDT)

12

I wouldn’t even bother with the SONY MDR-d66SL headphones. They are quite good, but pail in comparison to the cheaper Grado SR-60’s. Buy the Grado’s!

Posted by Mark Tate on July 30, 2003 at 12:18 PM (CDT)

13

I’ve updated some of the pages, and I’ve added some measurement pages.

Marc

Posted by Marc on August 11, 2003 at 12:00 AM (CDT)

14

Comparisons done on speakers alone are difficult, since they don’t produce a precisely discernible spatial field like headphones. With speakers the sound bounces around the room before reaching your ears. Good headphones are a must for objective results.

Also, you should get an app like EncSpot (for MP3) and examine all file details before comparing tracks of the same apparent bitrate. Even within the same encoder, the version will change over time and small improvements will appear. MP3s are definitely not created equal. There’s quite a bit of “analog” wizardry (perceptual coding) going on inside the files.

Beware of “golden ears” claims for any format above 192 kbps. IMO, LAME VBR (32 to 320 kbps range) at “standard” quality (“2”) or higher, sounds very close to the source material. Many sonic differences come down to small details like extra fuzz or attack/delay times on a certain cymbal strike. It is rarely a matter of one format or bitrate sounding like “crap” vs. another, unless the encoding is very poor, e.g. the old Xing watery effect.

Posted by Jim on June 23, 2009 at 2:26 AM (CDT)

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