| Author |
Thread: Source Quality |
    
Gold Member Username: Arande2
Rattle your ...
Missouri
Post Number: 2822
Registered: Dec-06
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| Posted on Wednesday, April 16, 2008 - 02:01 am: |
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I've read about how the importance of the quality of the source varies with system and type of music, so I am going to try using different bitrates on different systems and with different types of music to see the effects.
The reason why I am doing it? I've only read about it, but never actually experienced it directly.
The results?
The CD sounded much more realistic than the 100kb/s copy. The copy was compressed and everything just came out as one sound. Cymbals were also quite harsh. Saxophones are way more realistic on the CD. It just sounds much better.
And the most important thing to me - the CD was not fatiguing while the copy was very fatiguing, indeed. |
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Silver Member Username: Dmitchell
Ottawa,
Ontario
Canada
Post Number: 845
Registered: Feb-07
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| Posted on Wednesday, April 16, 2008 - 08:40 am: |
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Was this a 100 kbps MP3? That's pretty pathetic sound quality.
Even at 320 kbps you'd still hear a big difference between that and CD. |
Gold Member Username: Exerciseguy
Brooklyn,
NY
United States
Post Number: 1855
Registered: Oct-04
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| Posted on Wednesday, April 16, 2008 - 09:01 am: |
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Andre, with 2800+ post, I'm rather surprised you're just discovering that higher bit rates results in better sonics, what have you been listening to all this time? |
Gold Member Username: Frank_abela
Berkshire
UK
Post Number: 2883
Registered: Sep-04
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| Posted on Wednesday, April 16, 2008 - 10:39 am: |
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Andre,
the process of reducing a file to a 128kbps MP3 or whichever lossy compressed scheme you wish to use is not simply one where certain entries int he file are removed. It's a sample rate system which introduces errors too. So it's not just a question of how much less there is in the reduced file, but what mistakes there are in there too.
For example, I was reading an article by a respected recording engineer, Tony Faulkner, recently in HIFICRITIC magazine. In there he was expounding about how he wanted to send some recordings to the artists to go over the finer points of the recording and ensure he had the right cuts. Instead of burning a disc, he decided to send compressed MP3 files in a very commonly used bitrate (although he didn't specify what).
The artists were horrified at the (lack of) quality of the files and complained about it. So Tony did some investigation and found he had pre-echo with the files, almost like hearing the leading edge of the notes before they actually happened. He got in touch with the Fraunhofer Institute (the inventors of MP3 and MP4) abotu this and they confirmed that when the MP3 encoder is sampling the original PCM file, the way it samples can introduce timing errors which we perceive as pre-echo. the sample is slightly (a few milliseconds) ahead of where the note should be. With the leading edge of a note, that sounds like pre-echo. Apparently it's worse at certain sample rates than others but one of the worst is 128kbps which is also the most highly used bitrate in the world!
Thought this might be of interest...
Regards,
Frank. |
Gold Member Username: Frank_abela
Berkshire
UK
Post Number: 2884
Registered: Sep-04
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| Posted on Wednesday, April 16, 2008 - 10:43 am: |
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Incidentally, AAC - the lossy compressed format favoured by Apple with the iPod - is actually MP4. This is a much improved version of MP3 which is why when you convert an MP3 to AAC, it sounds better even though the samples are similar.
Of course, if you decode the original PCM to AAC, you have less of the timing errors.
Regards,
Frank. |
Gold Member Username: Exerciseguy
Brooklyn,
NY
United States
Post Number: 1856
Registered: Oct-04
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| Posted on Wednesday, April 16, 2008 - 10:51 am: |
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At the moment, I rip all of my music 320kbps MP3 (I also rip a lot of audiobooks @ 96kbps) for playback on my Creative Zen Vision M player.
I plan on re-ripping all of my discs to a lossless format soon, now that huge hard drives have come down in price. |
Silver Member Username: Dmitchell
Ottawa,
Ontario
Canada
Post Number: 847
Registered: Feb-07
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| Posted on Wednesday, April 16, 2008 - 11:39 am: |
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I ripped my CD collection FLAC, but I can still tell the difference listening to the same song ripped in FLAC vs CD. It's close, but not the same. I suppose a better quality DAC from my PC to system would help in this regard. |
Gold Member Username: Frank_abela
Berkshire
UK
Post Number: 2890
Registered: Sep-04
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| Posted on Wednesday, April 16, 2008 - 12:20 pm: |
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FLAC is a lossless format and should be no different to the uncompressed PCM. Of course, if the DAC section of the CD player differs substantially from the one you ripped the FLAC to, then the difference could be accounted for there. In essence you're saying that the connection to the DAC section and the DAC section itself is not as good as that in your CD player. |
Silver Member Username: Dmitchell
Ottawa,
Ontario
Canada
Post Number: 850
Registered: Feb-07
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| Posted on Wednesday, April 16, 2008 - 12:24 pm: |
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I think that's what I'm saying ;-)
Also, I think the fact that I'm running a somewhat long USB cable from my server to my DAC may have something to do with the diminished SQ. |
Gold Member Username: Arande2
Rattle your ...
Missouri
Post Number: 2823
Registered: Dec-06
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| Posted on Wednesday, April 16, 2008 - 06:03 pm: |
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CM, I was already aware of how they affected the quality, but I had never listened to the same music at different bitrates to actually hear the differences directly.
I also chose 100kbps to make the results more extreme. Yes, that is true - the codec you're using has a large effect.
There's a LOT of information on this topic. |
Gold Member Username: Nickelbut10
Post Number: 1377
Registered: Jun-07
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| Posted on Wednesday, April 16, 2008 - 08:02 pm: |
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"I ripped my CD collection FLAC"
Good man, the best way to do it.
"FLAC is a lossless format and should be no different to the uncompressed PCM"
Franks right. With certain FLAC ripping programs, you can find Jitter correction tools built in as well that can also come in handy. |
Silver Member Username: Pablo
Post Number: 112
Registered: Mar-06
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| Posted on Thursday, April 17, 2008 - 11:27 am: |
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EAC is a very good and simple program. Once you do initial set up you just put cd in and press one button. It takes 3-5 minutes per cd. I have over 500 cd's ripped in wave format. Bit more space then flack (15-20%) but some say bit better quality and storage is cheap now -1 tera for about $200 canadian. With squeezebox - this is the best solution I could have done.
Pablo |
