A Quick AAC bitrate question

[Razor70]

I hope someone can finally answer this question for me once and for all. I have read so many threads about bitrates that my mind is spinning. My question is this..When it comes to bitrate using AAC files..is going lower at 128 or is going higher say at 192 better quality sound. I get so confused on things when I hear that 128 is almost cd quality sound, but then I hear others saying that going higher is better. So, which is actually better for QUALITY sound 128 or 192?

And yes, I know it's really up to me to decide and I need to do ABX testing to see which I like the best, but in all actuallity which is better for the quality. Thanks.

[rockmyplimsoul]

The reason your mind is spinning is that you're listening to a range of opinions, and the only opinion that should matter to you is your own, hence the ABX testing that you need to do.

[studogvetmed]

If you want to throw out the bit of personal opinion. 192 is better quality because it keeps more information than the 128 file, thus the 192 is larger file size than the 128.

Now here is where it gets bumpy. Bitrate is really about getting optimal sound quality relatively to your space constraints. This is taken into account based on your use of the device and the equipment used with the device.

If you use the iPod as a portable device in the car, in loud situations with the stock ear buds, the 128 files should be perfectly fine if your ears can stand them (in those types of situations). However if you are going to be using your iPod in quieter environments, through a high quality stereo, or through a great set of cans, you might consider higher quality song files as the better equipment might expose flaws to your ears.

This is why the the ABX test is essential. What can you handle?

I mean strictly on paper 192 is better quality than 128 but then so is 256 better than 192. You could go all out and go up to 320, it's higher quality than the other three, but can year ears and equipment tell? Why not go lossless then? That is the question. Why have a 16 MB file when you can have a 4 megabyte file?

Take a breath, rip some files in various bitrates and do the test. You may be surprised. I've decided to not do the test. 128 is completely and utter fine for me. But you have to decide on your own.

[Code Monkey]

Definitely ABX test to see where your own hearing defines your cut off. I can ABX from lossless on some tracks at Nero Q 0.45 or lower (roughly ~150 VBR), so I run with Nero Q 0.5 (roughly ~170 VBR) where nothing is not transparent to my ear.

[pianomanss87]

Hi. I put every thing in at 192 ACC VBR. What is the ABX test?

Piano Man

[kornchild2002]

A blind ABX test is when you have a lossless file (exact same quality as the source CD) and a lossy file (such a s 192kbps VBR AAC). You then run a test using certain software (mainly foobar2000) to tell if your ears can hear the difference between the lossless file and lossy file. Recent listening tests have shown that 128kbps VBR AAC (both Nero and iTunes) provide pretty good results that are transparent (ie "CD quality") to many users. 192kbps VBR AAC of often considered to be overkill in that the bitrate is higher than actually needed. There are some people who have run the proper tests and need that high of a bitrate but, overall, it generally isn't needed unless you have trained your ears.

So that is why ABX tests are good; you use your ears to determine the proper bitrate that you need for your music and your equipment. Often times people suffer from the placebo affect. This means that they know that 192kbps is higher than 128kbps so they think that they can hear a difference between the two when in fact they don't. Blind ABX tests eliminate the placebo affect so all the results are based on what you hear.

[pianomanss87]

Thanks for the reply. I do have trained ears and have noticed a difference between 128 and 192 on some but not all songs. I listen to all kinds of music and wonder if different types of musice would be harder to tell the difference.

Piano Man

[kornchild2002]

Did you actually conduct a blind ABX test to determine these difference or did you just "hear" the differences? If you just "heard" the differences then you are probably suffering from the placebo affect. The only real way to tell is by conducting a blind ABX test. I know many people who say "I can hear a difference between the CD and 128kbps." I then sit them down with a nice pair of headphones in a quiet environment and run a blind ABX test for them. They fail every time even though I am using the iTunes AAC encoder at 128kbps VBR. Any differences that you hear outside of a blind ABX are in your head (no offense).

Also, different types of music tend to need different bitrates (theoretically). It all depends on the music (again, theoretically). Classical music, jazz, pop, pop/rock, rap, r&b, techno, dance, and hip-hop are all relatively simple by nature and usually don't require high bitrates to achieve good quality. Hard rock and metal usually require a higher bitrate due to their "wall of sound" technique and complex sounds. Live music may also require a higher bitrate as bands normally play songs live with more elements in them and the crowd can also add to the complexity of music.

I say theoretically though as I have conducted my own ABX tests and think that the iTunes AAC encoder at 128kbps VBR does a good job handling all types of music. I can ABX the differences between a 128kbps VBR AAC file and the source CD when in a quiet environment using my Sure e3c headphones. However, in a noisy environment (such as my campus), I cannot ABX between the two.

Also note that you won't hear a difference using the default white iPod earbuds and you definitely won't hear a difference when using computer speakers or home theater systems. You might hear a difference if you use studio speakers and your room is acoustically tuned. You see, speaker position has a lot to do with the way that you perceive sound quality. Moving the speaker 0.1 inches closer or further from your ear will alter the sound quality. There are also so many things in rooms that can absorb sound waves or reflect them in different directions thus altering the way music sounds.

That is why ABX tests are so important and that is why you must conduct them using your best set of headphones. Headphones eliminate any outside influences (such as the sound bouncing off of different objects) and put the speaker much closer to your eardrum. ABX tests eliminate any doubt and the placebo affect.

[pianomanss87]

Wow.

Thanks

Piano Man

[Razor70]

Originally Posted by studogvetmed

If you want to throw out the bit of personal opinion. 192 is better quality because it keeps more information than the 128 file, thus the 192 is larger file size than the 128.

Now here is where it gets bumpy. Bitrate is really about getting optimal sound quality relatively to your space constraints. This is taken into account based on your use of the device and the equipment used with the device.

If you use the iPod as a portable device in the car, in loud situations with the stock ear buds, the 128 files should be perfectly fine if your ears can stand them (in those types of situations). However if you are going to be using your iPod in quieter environments, through a high quality stereo, or through a great set of cans, you might consider higher quality song files as the better equipment might expose flaws to your ears.

This is why the the ABX test is essential. What can you handle?

I mean strictly on paper 192 is better quality than 128 but then so is 256 better than 192. You could go all out and go up to 320, it's higher quality than the other three, but can year ears and equipment tell? Why not go lossless then? That is the question. Why have a 16 MB file when you can have a 4 megabyte file?

Take a breath, rip some files in various bitrates and do the test. You may be surprised. I've decided to not do the test. 128 is completely and utter fine for me. But you have to decide on your own.

Thank you so much for your answer here, this is exactly what I was wondering about. I didn't know if because AAC is done for lower bitrates if going 128 was better than going 192 or the other way around. You totally answered my question, and yes I know it really is up to me on what bitrate I want to use (which I am totally fine with 128 VBR AAC), but I was a bit confused on how AAC worked more than anything. Thank you all for your help.

[kornchild2002]

Just remember that AAC really shines at bitrates between 96kbps to 160kbps. Technically 192kbps would be higher quality than 128kbps. However, at 192kbps, AAC (both Nero and iTunes) sound a lot like the Lame mp3 encoder. So you see, once you get up to 192kbps and higher, all encoders begin sound alike. Lame mp3 will sound like FhG mp3 will sound like iTunes AAC will sound like Nero AAC will sound like... That is why it is beneficial to use the AAC format at 96kbps-160kbps. After that, you might as well go with Lame mp3.

[Razor70]

Originally Posted by kornchild2002

Just remember that AAC really shines at bitrates between 96kbps to 160kbps. Technically 192kbps would be higher quality than 128kbps. However, at 192kbps, AAC (both Nero and iTunes) sound a lot like the Lame mp3 encoder. So you see, once you get up to 192kbps and higher, all encoders begin sound alike. Lame mp3 will sound like FhG mp3 will sound like iTunes AAC will sound like Nero AAC will sound like... That is why it is beneficial to use the AAC format at 96kbps-160kbps. After that, you might as well go with Lame mp3.

Okay another question then, with your analysis here Kornchild, if after 192 everything sounds the same..if I set my Itunes to 192 vbr and used it to rip into Mp3..would I be getting the same quality as a lame mp3? I find using itunes so much easier than EAC (which hasn't been working for me very well of late, well it's not letting me look up the cd information any longer), and I have tried CDex of late and I think it does a good job too (of course nothing is as good as EAC or dbpoweramp) and so I have toyed with the idea of using it with Lame 3.97. Would that be a better idea then? Thanks for the help everyone.

[kornchild2002]

In my opinion, yes, the iTunes mp3 encoder at 192kbps VBR will sound a lot like the Lame mp3 encoder at the same setting. There might be some minor differences here and there but overall, both will yield about the same quality. Lossy encoders compete more in the 128kbps-160kbps bitrate range. That is why Lame 3.98b8 is now considered to be transparent at -V 3 --vbr-new (~170kbps) while the older recommended transparency setting was -V 2 --vbr-new (~190kbps VBR).

I still wouldn't use iTunes to rip audio CDs though as you never know if it came across an error or not. Most of the time, when iTunes comes across an error while ripping, it will just plow through the error resulting in an audible flaw. You might want to look at using dBpowerAMP as that is my ripper of choice. Not only is it just as secure as EAC but it also uses the AccurateRip database and is now open to use multiple encoders. You can even update the version of Lame that dBpowerAMP uses. I also find that its interface is far easier to use than EAC's. I know that it costs about $20 but, in my opinion, it is $20 well spent.

[Razor70]

Thank you again Kornchild. I think I might look into dbpoweramp and see if I like it as much as you do. Using dbpoweramp as you do, how do you have your itunes set up for when you import your rips into it. Do you have the copy files feature turned off, or do you let it copy them and then erase them from your temp file you had them in? Thanks again for all your help.

[kornchild2002]

I let iTunes organize my library and copy any tracks. So I have dBpowerAMP rip to a folder on my desktop. I then drag-and-drop the files into iTunes. iTunes will copy them in and organize them to my liking. I then delete the files on my desktop.

I used dBpowerAMP to rip my CD's to Apple Lossless for having a backup so I trust it quite a bit. I think that it is much easier to use than EAC and some would even argue that it is more secure than EAC. I don't know if that is true or not but I do know that EAC can have an issue with an album while dBpowerAMP can rip it without any problems.

I then used foobar2000 to convert the Apple lossless files (certain ones) to -V 2 using Lame 3.98b8 (now 3.98 final release) so I can copy the files to my PS3. I used iTunes to convert them down to 128kbps VBR AAC for portable listening.