[Brent Hutto]

I'm starting to think encoding my music at around 170-190kpbs AAC for the iPod is way overkill. I've installed EAC and Foobar on my computer and am gradually re-ripping all my CD's and then encoding them as VBR .m4a files with a setting of -q 0.55 using Nero's command line encoder.

I also leave them on my hard drive as .wv files to be played via

Foobar v0.9.3.1 ==> E-MU 0404 ==> Portaphile ==> HD595

which allows me to do ABX comparisons. Not surprisingly, I can't hear a darned bit of difference in the -q 0.55 AAC versus the WavPack lossless files. So I tried an experiment. I coded a couple of very familiar tracks using a much lower setting of -q 0.30 which produces bit rates around 82kpbs on average. That pretty darned compressed ain't it?

I can't tell A from B comparing those 82kpbs files from the lossless ones. Now I'm not talking about identifying them with ABX, I mean I can play A and B over and over, knowing which is which, and they still sound perfectly identical. They both sound great, whether played through the computer for an ABX test or comparing WavPack on the computer to AAC downloaded to my iPod (although it's hard to match levels between the iPod and computer).

I guess I'll still to -q 0.55 for peace of mind since I have plenty of hard disk space and the new iPod I'm getting next month has 30GB of storage. But it's kind of cool that Nero can squeeze music down so small and still sound great, although I certainly haven't tried it with piano music or cymbals or whatever.

 

[Herandu]

I use VBR as well, and it does the trick for me.
But when we are talking about anything that has to do with compressed music, I don't expect the same level of quality. The ambience tend to be flat IMHO.
I keep my CDs backed up as image files, instead of wave files even. I 'think" I can hear a difference between the two. Might be pure perception, but it keeps me happy.

 

[Comfy]

Tin ears?

 

[stevenkelby]

Hearing a difference depends largely on your equipment. I can't hear a difference between 128 and lossless through my PC speakers but can hear a difference between 320 and lossless through my main stereo.

 

[Brent Hutto]

Until I got my E-MU installed last night I had figured that everything sounded alike in an ABX test because of the poor quality of the built-in sound on my computer. But now assuming that I had everything configured correctly (a big assumption) supposedly I'm having Foobar send the 44.1KHz data stream by ASIO directly to the E-MU 0404 with no mixers or processing in the path. Then it's the Portaphile and headphone.

That "should be" virtually as good as my main listening setup which is an old Adcom CD player, line-out to the Portaphile and then to the headphone. So the only real drawback to the computer-listening setup vs. the CD player is the Adcom is in a quiet room whereas the computer whooshes a little (plus the chair at the computer isn't as comfortable as my recliner).

 

[Klefbek]

Quote:

Hearing a difference depends largely on your equipment. I can't hear a difference between 128 and lossless through my PC speakers but can hear a difference between 320 and lossless through my main stereo.

It is not just dependant on equipment. There are more factors included like:

- experience of listener (know what to look for)
- difficulty of sample to encode (is it a problem sample or not)

It's for example not so difficult to produce a sample with LAME at 320 kbps that can be ABX-ed by most people using 5 dollar headphones plugged into a laptop. The reverse is also true: there are plenty enough samples that most people have trouble ABX-ing encoded with something like LAME -V5 on high-end equipment and ideal listening conditions.

All in all, I have to agree with Brent Hutto that per size most modern lossy audio encoders (e.g. LAME, Nero, Vorbis) deliver excellent quality. It is not always perfect/transparent, but that is inevitable due to the concept of lossy encoding. And depending on the specific purpose, sacrificing a little bit on quality might be a small loss considering the size gains.

 

[stevenkelby]

All excellent points but I think equipment is the main one.

I haven't played much with different encoders though. Sounds like maybe I should!