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gt3b2 better than aotuvb5 @ q6?!?
post Dec 5 2007, 17:10
Post #1

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Posts: 8
Joined: 30-November 07
Member No.: 49146

hi guys!

first off: i am new to this forum so if i am asking stupid questions, please be gentle with me! ;-)

i have been an avid user of the gt3b2 vorbis encoder for a long time now. i use it at q6 and find it gives outstanding results. as a matter of fact, i find it extremely difficult to ABX a difference between it and the original wav file! :-)
(whoever wrote gt3b2 -> great job!)

but knowing it is very old i checked here (THE authority in music encoding ;-) for any new developments.

sure enough: aotuvb5 is HA's recommended vorbis encoder. no prob - i happily downloaded and tested it (also @ q6) vs. gt3b2.

then my surprise: there was a clear difference between the two, which i could clearly hear in an ABX test on some more "tricky" music pieces:

WinABX v0.42 test report
11/30/2007 11:40:24

A file: C:\Temp\Ripped Files\Iaora Tahiti.02.Mouse on Mars.Kompod_aotuvb5.wav
B file: C:\Temp\Ripped Files\Iaora Tahiti.02.Mouse on Mars.Kompod_GT3B2.wav

Start position 00:00.0, end position 04:08.4
11:47:36 1/1 p=50.0%
11:48:18 2/2 p=25.0%
11:48:45 3/3 p=12.5%
11:49:27 3/4 p=31.2%
11:50:06 4/5 p=18.8%
11:51:07 4/6 p=34.4%
11:52:04 5/7 p=22.7%
11:53:11 6/8 p=14.5%
11:54:14 7/9 p=9.0%

WinABX v0.42 test report
11/30/2007 11:55:06

A file: C:\Temp\Ripped Files\Iaora Tahiti.06.Mouse on Mars.Kanu_aotuvb5.wav
B file: C:\Temp\Ripped Files\Iaora Tahiti.06.Mouse on Mars.Kanu_GT3B2.wav

11:55:29 1/1 p=50.0%
11:55:50 2/2 p=25.0%
11:56:09 2/3 p=50.0%
11:56:44 2/4 p=68.8%
11:57:18 3/5 p=50.0%
11:57:45 4/6 p=34.4%
11:58:44 4/7 p=50.0%
11:59:22 5/8 p=36.3%
12:00:05 5/9 p=50.0%
12:00:27 6/10 p=37.7%

WinABX v0.42 test report
11/30/2007 12:00:56

A file: C:\Temp\Ripped Files\Unison.03.Angels & Agony.Unison_aotuvb5.wav
B file: C:\Temp\Ripped Files\Unison.03.Angels & Agony.Unison_GT3B2.wav

12:01:15 1/1 p=50.0%
12:01:38 1/2 p=75.0%
12:02:28 2/3 p=50.0%
12:02:44 3/4 p=31.2%
12:03:52 4/5 p=18.8%
12:04:10 5/6 p=10.9%
12:04:40 6/7 p=6.2%
12:05:40 7/8 p=3.5%
12:06:01 8/9 p=2.0%
12:06:12 9/10 p=1.1%

WinABX v0.42 test report
11/30/2007 12:06:38

A file: C:\Temp\Ripped Files\Zephyr- 48_24_aotuvb5.wav
B file: C:\Temp\Ripped Files\Zephyr- 48_24_GT3B2.wav

12:07:09 1/1 p=50.0%
12:07:53 2/2 p=25.0%
12:08:19 3/3 p=12.5%
12:08:34 4/4 p=6.2%
12:09:06 4/5 p=18.8%
12:09:29 5/6 p=10.9%
12:10:22 6/7 p=6.2%
12:10:55 6/8 p=14.5%
12:13:16 7/9 p=9.0%
12:13:56 8/10 p=5.5%

so far so good. BUT: to me gt3b2 sounds BETTER than aotuvb5?!?!?

in my ears:

more "open", better staging/positioning (like in a concert hall) and delightful lightness.
but a slight tendency to "muddy" sound and seems to make some passages louder (dynamic loss?).

somehow "darker", more "closed" sounding, like in a small room, more restrained.
however, instruments and voices seemed to sound more precise/"clean" and there was less apparent loudening of certain passages.

are there some special settings i need to do to aotuvb5 i simply missed? (yes, i read the wiki) or is it my choice of tracks? (most is 16bit/44kHz electronic, but "zephyr" is a 24bit/48kHz acapella choir) is there a possibility that the decoder i use (a squeezebox 3 with optical dig. out) works better with gt3b2 than with aotuvb5?

thanks for your thoughts, guys! :-)
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post Dec 7 2007, 10:17
Post #2

Group: Members
Posts: 8
Joined: 30-November 07
Member No.: 49146

i will run a test vs. the orginal wav files soon, just to make sure. and, as you guys rightly pointed out, that would show me which comes closer to the original. and, of course, any differences introduced by vorbis.

wierd thing is, i tried an ABX vs. the original many months (years?) ago to determine wich q-level would be good enough for me and if i would use gt3b1/2 or xiph reference.
i did this unti my "guessing probability" consistently went p>50%.
turns out gt3b2 (At the time actually b1) sounded "transparent" to me @ q6, whereas xiph reference only @ q8. stll allowing for gt3b1/2's higher bitrates, the compression was better, so i went with it.
aotuvb at the time (it was said) was primarily optimized for lower bitrates, which was why i didnt even bother with it.

@JAZ: thanks for clarifying. maybe i need to as well: i actually performed an ABXY test. becasue of that, there is indeed a chance that i was only picking the encoder whose sound i "knew" better from experience. ;-)

bearing that in mind - if i am looking for the encoder that *subjectively* sounds best to me (including any and all artifacts and problems), i would still ABX the two *lossy* files, no?

i am starting to think that there could be a difference between *objective* and *subjective* quality here. quite similar to the way a tube amp sounds better to my ears than any solidstate amp, even though it's tech specs are almost always inferior.
to me, "musicality" is at least as important as "objectivity" and "precision"... ;-)
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