iPod Digital music audio quality

Michael CM1 said:

Ever since discovering the Amazon MP3 store a few weeks ago, I have started to wonder about audio quality between different formats available. Doing a Wikipedia search didn't make anything clearer.

What is the best way to get high-quality sound? Yesterday, I could've sworn that my ears told me some 256kbps MP3s had much higher quality, but it's so hard to tell from a set of standard iPhone earbuds. Most of my music is in 128kbps quality, so it is quite difficult to know. Most of the iTunes music is in 128kbps, which stinks when Amazon sells about everything at 256kbps without DRM (what gives, record companies?).

I also want to know opinions on AAC vs. MP3. Shoot, throw MP4 audio in there as well. I have pretty good ears (did the marching band thing) so I can "appreciate" the better quality. I just don't know the ins and outs of all the digital formats and I hope there are a few geniuses on here to sort a bit of it out.

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I'm no audio expert, but I think AAC files sound better than equivalent MP3 files. I concluded this by listening to and comparing the same songs downloaded from the iTunes store (256 kbps AAC) and Amazon.com (256 kbps MP3). I just think the AAC files sound richer and more natural, closer to the original file on CD. Not scientific, I know, but just my personal opinion.

Hey Michael you seem to be a bit confused about your options, can't blame you with all the tec people making unessesary complications out of everything, including wikipedia. I will try to exlain a few things but you will have to read around a bit too. Basically the three competing lossy formats are mp3, wmv, and apples aac. Lossy means that all of them compress the original wav file on a cd to some extent based on the psychoaccoustics of each compression, i.e. cutting down on frequencies that might not be noticeable by the human ear, except some very rare ears maybe, or even imperceptible to any human ear.

Of course the most widespead of these is the mp3. It is said that at 128 kbs mp3s are nearly as good as cds, which means that they are a bit worse. I would agree with that. The best quality mp3s you can get with 320 mbps compression and to me these sound near identical to cds, I personally cannot discern which is which and (let's be honest) almost nobody can. At 256 amazon mp3s are great too, not the best but great. Of course you have to sacrifice disk space as the 320 are more than double the 128 in size, but nowadays disk size is getting larger and larger. Apple's propriety format is the aac, very similar to mp3 files, which is supposed to be a bit better and opinion is divided as to whether it actually is (same goes for wmv), you can read some test run around the web to gauge which one is better. To me they are prety much the same.

Another option you have, which for me is the default when ripping purchased cds is a lossless format, i.e. one which cuts down the data but which is identical to the original wav only compressed. Apple lossless, wmv lossless and flac are good options here. Wmv and flacs offer better compressions to apple's format at around 5%. But since switching back to itunes from windows media player I have personally reconverted everything to apple lossless.

So, in a nutshell, if you don't mind the space issue go lossless for your own cds, if you buy mp3s online see that they are at least 192 kbps with 256 and 320's being what you aim for. Hope I ve helped a bit.

Way to go Michael I think you are taking the wisest route quality/size -wise with 256 kbps files. Yes lossless files can be beasts better suited for an imacs 500 gb drive than the iphone for sure.

As for your question, I can't imagine even the most ardent supporter of itunes and aac that they could claim that at 128 they are better than a 256 mp3 file. If we were comparing a 128 aac file and a 160 or 192 mp3 file one could possibly make a case for aac, but at 256 its the 256 mp3 files hands down.

AAC is clearly better than MP3. Broadly speaking MP3 is the equivalent sound quality of one bitrate notch (i.e. 96K / 128K / 160K / 192K) worse than AAC at an equivalent bitrate.

At 256K though, as long as both are good encodes the perceptible difference has pretty much evened out, especially for portable listening - even with high-quality earphones.

But MP3 is far more universal. It means your music library isn't locked down to a select few players that understand AAC. Unfortunately the availability of the Sony/Nokia (among others) co-developed AAC playback from a wider range of players simply boils down to money, not because it's an Apple-friendly format (they're just a licensee): Many of the smaller manufacturers find the licensing costs for MP3 alone - which everyone expects - high enough given their position and forego licensing AAC, and still more don't bother for other reasons. If it was more universal among all sorts of players it would be a great all-round codec.

Lossless is where it's at if you have a good home system and want to play back through that, but taking those files portable do involve significant tradeoffs - much larger file size, decoding overhead and corresponding battery suckage (especially on HDD players) as an example. However many dedicated portable so-called audiophiles (in reality, just nerds) do persist with portable DACs, headphone amplifiers, lossless audio and high-quality audiophile headphones on which they won't be able to hear anything worthwhile due to background noise

Such audiophiles notwithstanding, there is a school of thought that says that due to 'hugely' inferior audio quality of the iPods vs the leading also-rans on an iPod it's pointless worrying about quality of bitrates because it's going to sound crap anyway. I don't think the iPod is the best for audio, but it's far from crap - and certainly up to and including 320K, given the right environment and the right material higher quality audio files should make a quantifiable difference to your music enjoyment. Personally I have other players I use if I really want that last couple of db SNR of if I just want to enjoy a better geek toy, but the sheer convenience and perfectly acceptable quality of iPod keeps me using it on an everyday basis.

The following has almost no bearing on Apple users, but open source audio formats (Ogg - lossy, FLAC - lossless) are very popular among the Linux / generic geeks. They provide excellent audio quality for the size and are supported on predictably the geekier players you can buy.

Hey sesshi great post! Of course with aac to mp3 comparison you are voicing your opinion, which let's admit is far from being universally accepted. Also I don't think you are suggesting 256 mp3 files even with 128 aac files, that would mean aac engineers have somehow managed to half the size but keep the same quality. This of course is impossible. 128 aac files are nowhere near a 256 mp3.

AAC actually retains the high and the lows, unlike Mp3. I was surprised that AAC sounds much closer to CD quality than Mp3s are.

Keep in mind AAC is Mp4 which is >10 year newer technology than Mp3. Thus Mp4 sounds better at the same bit rate or slightly lower bit rate.

I have been ripping them at AIFF for many years. No need to figure out which format is what. Harddrives are cheap. (I put the original CDs in a box for backup incase a file gets damaged). 5 years ago I used to carry an external harddrive that needs power adapter, but since few years ago I have been using an external bus-powered firewire Lacie Mini Big Disk.

I use an iPod with a third party line-level output dock (yes they make those) for backup of my DJ system. iPods are perfectly capable for professional applications (at least as DJing is concerned). Thus for those who doesn't think iPods are best for audio, don't know what they are talking about (yes, don't know how to utilize a tool to full potential = no idea what they are doing).

The headphone outputs are not bad for emergencies, if you set the volume of iPod output properly. But for portable applications, no portable audio player can compare to audiophile system of course.

jackfrost123 said:

Hey sesshi great post! Of course with aac to mp3 comparison you are voicing your opinion, which let's admit is far from being universally accepted. Also I don't think you are suggesting 256 mp3 files even with 128 aac files, that would mean aac engineers have somehow managed to half the size but keep the same quality. This of course is impossible. 128 aac files are nowhere near a 256 mp3.

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No. Taking what I said and making an example, a 128K AAC file is broadly equivalent to somewhere between a 160K/192K MP3. The 128K rate is what many people think about, and AAC is definitely superior since there is better frequency reproduction and considerably reduced artifacting / aliasing. Once you get to 256K though - there's not a huge amount in it anymore.

Consultant said:

Thus for those who doesn't think iPods are best for audio, don't know what they are talking about (yes, don't know how to utilize a tool to full potential = no idea what they are doing).

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It's more the level of third-party support due to sales and intelligent design / legacy carryover of the dock that makes them suited to make third-party semi-pro / pro apps. It's not due to the inherent technical superiority of the iPod platform.

It's out there that the iPod does have some audio stage and some codec (both hardware/firmware) shortfalls. Those who don't think iPods are best for audio do know what they're talking about in that very narrow regard while failing to take into account how you'd use an MP3 player on a daily basis, much like those who nerd out on OS's believe that OS X (or Linux) is the best OS, but fail to take into account other requirements for general-purpose computing.

For me, everyday usability in order to simply enjoy the music at a generally decent quality is far more important - and I'll take the most usable, the most stable, the best accomplished overall package over a perfectly acceptable slight dip in audio quality / audio features or other minor annoyances.

@Sesshi

No. Taking what I said and making an example, a 128K AAC file is broadly equivalent to somewhere between a 160K/192K MP3. The 128K rate is what many people think about, and AAC is definitely superior since there is better frequency reproduction and considerably reduced artifacting / aliasing. Once you get to 256K though - there's not a huge amount in it anymore.

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Well you are wrong about that and you'd have to convince a lot of people otherwise, that's for sure, because left right and centre listening tests that have been conducted prove otherwise.
Like here for exampe:
http://www.rjamorim.com/test/64test/results.html

Or here:

http://www.planetofsoundonline.com/articles/compression1.html

Quoting directly:

On the whole, there weren't any surprises. My observations echo what most people have said about AAC vs. MP3. AAC is higher quality at the same bit rate, so you can use a smaller file to achieve the same quality as MP3 which is a good thing for portable and computer users. Ultimately, both formats still sound pretty bad in their practical ranges compared to CD. I didn't test 256 or 320 kbps because it's impractical for most users to use these encodings. The Apple Music Store for example uses 128 kbps, and if you have room for 320 kbps and you care about sound that much you'll probably use AIFF or just play the CDs themselves.

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and moreover, cases in point where an mp3 endoder can be BETTER than an aac one:

I've received tons of e-mail thanking me for the test, and many people have suggested that I use OGG or MP3 with LAME/VBR because they're better than the iTunes standard encoder.

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The rjamorim test is an oft-referred to one, and is not only out of date but I think does some codecs a disservice. The worst one in the test for example would now be the best (as well as now largely defunct). ATRAC3Plus RIP... you will be missed, especially your (potentially... only if it wasn't solely implemented on the worst piece of audio management software ever written, Sonicstage) awesome implementation of Lossless.

I use LAME @ 256K for my rather overcomplicated library mainly because it was the easiest to invoke from a programmatic point of view (I use a rather unique Lossless/Lossy sync software), but personally I think it's a tad overrated. It got a lot of press in AAC vs MP3 tests during the time it was cool to hate the 'iPod Sheep' due to a lot of morons thinking the A in AAC stood for Apple. You can get excellent results by tweaks, but in general even the Apple MP3 encoder generates perfectly acceptable results these days, applicable to my opinions.

So in essense you're saying you stand corrected. I am happy to hear that. I am also happy to hear that you have chosen lame mp3 as your standard codec despite your long diatribe on aac and its superlative merits. This is what I use too.

Is English your first language? It's in effect my third, and I find that my adherence to some semblance of proper grammar and syntax can throw off some locals. I'll be happy to rephrase it if you like.

That's not a problem buddy! It's ok, I understand.

Amen for the car, and the 30 c. Amen!

Yeah, high bit rate AAC definitely would do it for what you want to do.

I would not call AAC (mp4) proprietary, because it's as proprietary as mp3.

Dollar per dollar, car radios are usually lower quality in terms of sound quality (but they have higher volume), due to amount of road, engine, and ambient noise in a car.

People need to read Hydrogen Audio more

AAC is better than MP3 at the same bitrate at 128kbps.

But when you get higher up, like 192 and above, LAME MP3 is pretty much king.

LAME 3.98 -v 0 --vbr-new is basically the best you can get for lossy encoding. The average bitrate is around 240kbps, but it basically uses all the bits it needs.

Plus LAME has been fine tuned by listening tests and community input to achieve the best overall quality.

Blind listening tests prove it too.

I stopped buying music on iTunes because of the quality and DRM. I went back to getting deals on CDs and just ripping them first to FLAC for archive then transcoding them to LAME using that setting. Better than my iTunes purchases ever sounded.

The only bad thing is that now I need to go and buy some CDs of stuff I bought from iTunes because the quality just isn't satisfying at all any more.

mosx said:

People need to read Hydrogen Audio more

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People have mentioned various sources for where you can look at tests of possibly dubious veracity and methodology, but what's wrong with playing it back yourself on the best gear you can muster in a blind test at the same listening levels, having a hearing test beforehand to make sure you aren't as deaf as a post (as I suspect many so-called audiophiles are)?

mosx said:

People need to read Hydrogen Audio more

AAC is better than MP3 at the same bitrate at 128kbps.

But when you get higher up, like 192 and above, LAME MP3 is pretty much king.

LAME 3.98 -v 0 --vbr-new is basically the best you can get for lossy encoding. The average bitrate is around 240kbps, but it basically uses all the bits it needs.

Plus LAME has been fine tuned by listening tests and community input to achieve the best overall quality.

Blind listening tests prove it too.

I stopped buying music on iTunes because of the quality and DRM. I went back to getting deals on CDs and just ripping them first to FLAC for archive then transcoding them to LAME using that setting. Better than my iTunes purchases ever sounded.

The only bad thing is that now I need to go and buy some CDs of stuff I bought from iTunes because the quality just isn't satisfying at all any more.

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Actually, from what I understand, it really depends on what genre of music you're going to encode as to what encoder/setting you use. For me that's WAY to much work. If I want to listen to great audio I go with the original CD on my home theater system or Neural Surround from DirecTV's XM stations (freaking amazing 5.1 music). Otherwise it's AAC @192kbps for my iPod docked to my Pioneer car stereo. Good enough for road noise.

Michael CM1 said:

I need to complain again about the stupid iTunes Plus upgrade charge for songs I already bought.

WHAT THE F IS THIS ALL ABOUT? I mean seriously. They cost exactly the same when you buy them right now, but I only have the option of paying 30 cents/song to upgrade THE WHOLE THING? What kind of a jack is this? I could understand maybe a one-time fee of like $2 or something to cover whatever costs. But right now they want to charge me about $45. My response rhymes with "shucks no!"

iTunes has the best store out there overall, but they're starting to get beaten by other places for audio quality and stuff like this.

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I'm also pretty unhappy with that upgrade fee; if they said it was for bandwidth, then I'd understand a 1 cent upgrade fee, but 30 cents is way too much.

People have mentioned various sources for where you can look at tests of possibly dubious veracity and methodology, but what's wrong with playing it back yourself on the best gear you can muster in a blind test at the same listening levels, having a hearing test beforehand to make sure you aren't as deaf as a post (as I suspect many so-called audiophiles are)?

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Well, I'm 26 and the high pitched sound that emits from CRT TVs and monitors is loud enough to me to make me not use them. So I know I'm not deaf.

But sure, people can see what sounds best to themselves.

Nobody is stopping you from thinking that the awful ATRAC3plus code is good. Everyone else (including me, I owned atrac3 and actrac3plus gear) thinks it sounds terrible. But if you like it, go ahead and use it.

Actually, from what I understand, it really depends on what genre of music you're going to encode as to what encoder/setting you use. For me that's WAY to much work. If I want to listen to great audio I go with the original CD on my home theater system or Neural Surround from DirecTV's XM stations (freaking amazing 5.1 music). Otherwise it's AAC @192kbps for my iPod docked to my Pioneer car stereo. Good enough for road noise.

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I never thought the XM stations on DirecTV sounded very good. Granted they sound better than the actual XM broadcast (XM sends the music uncompressed over to DirecTV which then uses 192Kbps MP2, thats MPEG 1 Layer 2, to compress it). But they don't sound very good in the whole scheme of things.

For me personally I encode all of my music using LAME -v 0 --vbr-new. I have my PC right now re-converting my music from my lossless archives made from my CDs to that same setting with LAME 3.98. It's chewing through about 600 songs an hour right now.

When I'm listening to music on my surround sound system, its not quite as good as the CD but its good enough, considering I generally have my Mac hooked up to it running optical output. In that case, thousands of songs at about 95% CD quality overrule "full quality" based on convenience alone.

I need to complain again about the stupid iTunes Plus upgrade charge for songs I already bought.

WHAT THE F IS THIS ALL ABOUT? I mean seriously. They cost exactly the same when you buy them right now, but I only have the option of paying 30 cents/song to upgrade THE WHOLE THING? What kind of a jack is this? I could understand maybe a one-time fee of like $2 or something to cover whatever costs. But right now they want to charge me about $45. My response rhymes with "shucks no!"

iTunes has the best store out there overall, but they're starting to get beaten by other places for audio quality and stuff like this.

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Yeah, I agree.

The upgrade fee is stupid. All of the WMA stores (Napster, Real, etc) give you free upgrades when they update the quality of their catalog. But Apple charges.

Amazon is higher quality than all and DRM free. Whatever I buy online from now on will be from them. CD or MP3.