Lossless audio - is it really that important? - Yes it is!

[Deciazulado]

Originally Posted by stevei

You have to be a little careful with these things, though - I once encoded a pro logic matrixed stereo file at 128kbps and it sounded TERRIBLE. At 192kbps it was fine, and I could have easily assumed the difference was due to the bitrate. However, a more detailed investigation revealed that the codec was configured to use joint stereo at 128 and stereo at 192. Switching it to use stereo instead of joint stereo at 128 made the problem go away at 128.

You think I don't know what I'm doing? I know what you're doing.


btw I was listening to The Beatles in surround before they ended

[stevei]

Originally Posted by Deciazulado

You think I don't know what I'm doing?

It wasn't my intention to give that impression. Perhaps if I'd said "one has to be a little careful" instead of "you have to be a little careful"? I don't know you well enough to know whether you always know what you're doing or not, so don't have an opinion either way.

On the other points people have raised, some people seem to be misinterpreting some of the things said up to now. One test said that most people can't tell a 128kbps AAC encode from a CD. This is NOT the same as a 128kbps mp3 encode, which tests have found the majority of people CAN tell from a CD, and my own blind tests showed I can reliably tell this from a CD. I believe that a 640kbps DD 5.1 track will be significantly higher quality than a 128kbps mp3, probably more similar to a 256kbps stereo mp3, so a more relevant test would be whether people can tell a 256kbps mp3 from the original CD. The one test I found that seemed to have tested this in a scientific manner found no ability to discriminate between these two, and they were using skilled listeners, e.g. one was a professional sound engineer.

What I do intend to do sometime in the interests of science is to listen to different bitrate tracks while wearing earplugs to see if it affects my ability to discriminate between different bitrates. Given how perceptual encoding works I find it highly plausible that impaired hearing can result in a greater ability to discern the artifacts that would otherwise be masked by louder sounds.

[MatrixS2000]

Originally Posted by stevei

What I do intend to do sometime in the interests of science is to listen to different bitrate tracks while wearing earplugs to see if it affects my ability to discriminate between different bitrates. Given how perceptual encoding works I find it highly plausible that impaired hearing can result in a greater ability to discern the artifacts that would otherwise be masked by louder sounds.

LOL and you don't think earplugs will mask any artifacts????

This is getting funnier each post!

[stevei]

Originally Posted by MatrixS2000

LOL and you don't think earplugs will mask any artifacts????

Suppose the earplugs cause a rapid drop off in volume above 1khz, just for illustration. Then suppose you listen to something that has at one point in it two sounds at 900hz and 1100hz, with the 1100hz sound quite a bit louder. The perceptual encoding discards the 900hz sound, and normally if you can hear the 1100hz sound you won't notice this has happened, but if you have the ear plugs in and can't hear the 1100hz sound, it will be like night and day because in the original you'll hear a 900hz sound and it won't be there in the compressed version.

[MatrixS2000]

Originally Posted by stevei

Suppose the earplugs cause a rapid drop off in volume above 1khz, just for illustration. Then suppose you listen to something that has at one point in it two sounds at 900hz and 1100hz, with the 1100hz sound quite a bit louder. The perceptual encoding discards the 900hz sound, and normally if you can hear the 1100hz sound you won't notice this has happened, but if you have the ear plugs in and can't hear the 1100hz sound, it will be like night and day because in the original you'll hear a 900hz sound and it won't be there in the compressed version.

If you have 2 tones - one at 900 hz and the other at 1100 hz, doesn't mean you can't hear the 900 hz even if the 1100 hz tone is louder - that is how music works! Some sounds are louder than others, you don't throw the quieter stuff away, you HEAR that it is lower in volume.

That scenario you just described is an audiophiles nightmare and illustrates exactly WHY we want LOSSLESS audio!

[stevei]

Originally Posted by MatrixS2000

If you have 2 tones - one at 900 hz and the other at 1100 hz, doesn't mean you can't hear the 900 hz even if the 1100 hz tone is louder - that is how music works! Some sounds are louder than others, you don't throw the quieter stuff away, you HEAR that it is lower in volume.

That scenario you just described is an audiophiles nightmare and illustrates exactly WHY we want LOSSLESS audio!

But these encoding schemes were developed based on tests of what people can actually perceive, e.g. the section on Masking in this article:
http://www.soundonsound.com/sos/may00/articles/mp3.htm
What you seem to be saying is that the whole basis of perceptual encoding is wrong and the people who developed these encoding systems didn't have a clue what they were doing.

I still have yet to see a study showing that people can discriminate between 256kbps mp3 and the original CD. Please provide a link if you're able to locate a double blind study that shows people can discriminate in this way.

[MatrixS2000]

Here is part of the title from your link...

"Most of us are aware that MP3 encoding offers a way of drastically reducing the size of digital audio files while preserving reasonable sound quality."

As soon as I read that - I could careless about that article - it's junk to an audiophile.

I am not interested in reasonable audio quality. The only time I listen to my MP3 player is when I am working out or walking the dog...it's only on as a secondary event to the primary event which is working out or walking the dog.

When I listen to music or watch a movie, it's the primary event that is taking my attention.