Led Zeppelin

Just what the name says.
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krabapple
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Postby krabapple » Thu Aug 11, 2005 4:06 pm

Nope. Can't do it at work, haven't remember to at home. Wouldn't be what I'm aiming at anyway.
What I'll is purely objective: rip the same track from both versions, run Audition frequency profiles and stats on both, see what shakes out.
"I recommend that you delete the Rancid Snakepit" - Grant

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krabapple
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Postby krabapple » Thu Aug 11, 2005 9:01 pm

..and having begun the investigation, loading 'Communication Breakdown' old and new, it looks right off the bat like one is phase-inverted compared to the other....

...and possibly the channels have been switched as well.

My my, what a mess.
"I recommend that you delete the Rancid Snakepit" - Grant

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lukpac
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Postby lukpac » Thu Aug 11, 2005 9:08 pm

Yes, I already mentioned the channels being switched...
"I know because it is impossible for a tape to hold the compression levels of these treble boosted MFSL's like Something/Anything. The metal particulate on the tape would shatter and all you'd hear is distortion if even that." - VD

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krabapple
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Postby krabapple » Thu Aug 11, 2005 9:12 pm

Good, saves me the trouble of verifying it further. :lol:

So, here are stats for the 'raw' (not normalized) files (numbers between colums are averages)

Code: Select all


                           Diament              Marino               
                       Left       Right        Left      Right   
Peak Amplitude:           -1.6    -1.0          0.0     0.0         
Possibly Clipped:          0.0     0.0          0.0     0.0         
DC Offset:                -0.7    -0.4          0.0     0.0         
Minimum RMS Power:       -46.9   -49.7          inf     inf         
Maximum RMS Power:       -11.2   -10.1         -8.7    -8.4         
Average RMS Power:       -17.2   -15.3  -16.2 -14.1   -14.6 -14.3
Total RMS Power:         -16.6   -14.8        -13.6   -13.9         
DR                        15.6    14.2   14.9  14.1    14.6   14.3



and after the old version is normalized (and offset-corrected)

Code: Select all

                     Left     Right     
Peak Amplitude:      -0.6     0.0     
Possibly Clipped:     0.0     1.0     
DC Offset:            0.0     0.0     
Minimum RMS Power:  -96.3   -96.7     
Maximum RMS Power:  -10.2    -9.1     
Average RMS Power:  -16.2   -14.2  -15.2
Total RMS Power:    -15.6   -13.8     
"I recommend that you delete the Rancid Snakepit" - Grant

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krabapple
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Postby krabapple » Thu Aug 11, 2005 9:47 pm

and after accounting for channel switching, from frequency analysis (using the normalized file for the old version) from about 7K on up, both channels of the new version are always *cut* anywhere from 0.1 dB to 2.3 dB up through 15 K. The two channels aren't EQd the same.

From about 100 to 4K, there's always anywhere from 0.1 to 2.3 dB boost in one or both of the channels in the new one, compared to old -- peak difference being in the right channel (new version) circa 2200 Hz.

Below 100 Hz. the left ch of the new is cut a tiny bit compared to old, the rt ch is boosted 1-1.5 dB.
"I recommend that you delete the Rancid Snakepit" - Grant

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lukpac
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Postby lukpac » Thu Aug 11, 2005 10:02 pm

Yeah, that pretty much jives with what I was hearing. Although I didn't hear any huge differences between the channels.
"I know because it is impossible for a tape to hold the compression levels of these treble boosted MFSL's like Something/Anything. The metal particulate on the tape would shatter and all you'd hear is distortion if even that." - VD

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krabapple
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Postby krabapple » Thu Aug 11, 2005 11:47 pm

lukpac wrote:Yeah, that pretty much jives with what I was hearing. Although I didn't hear any huge differences between the channels.


Actually the differences are much more 'regular' than I thought. The shapes of hte EQ curves for left and rt channel are essentially the same, just the magnitude of change varies (but it varies consistently too). Check out this graph of the frequency boost /cut of new versus old for both channels (download as a Word doc), it gives a much simpler picture of what's going on than my description above:


Communication Breakdown
"I recommend that you delete the Rancid Snakepit" - Grant

Andreas
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Postby Andreas » Sat Aug 13, 2005 8:43 am

Comparison: Led Zeppelin IV
Version 1: Atlantic 19129-2 , Europe: 250008, Made In West Germany By Polygram, "target CD"
Version 2: Atlantic 7567-82638-2, remaster

There are no swapped channels on my CDs. The harmonica in When The Levee Breaks is in the left channel, on both CDs.

Where are the supposed dropouts on the original CD? I guess I was not paying attention to that.

The Battle Of Evermore has very prominet hiss on the old CD, much more than the remaster. But that is the only song for which this is true! Hiss levels are about the same on all other songs.

The remaster has a slightly pronounced upper midrange, but not as apparent as on III or some tracks on HOTH. The drums sound pretty similar on both CDs.

The fades are better on the older CD. On the remaster, the fades are a bit faster, and the hiss is faded down as well. On the older CD, they just let it roll.

Now what is really improved on the remaster? It was implied in many reviews that the original CD was "obviously" from an inferior tape...where can this be heard? I am no trying to be argumentative, I just want to find out what others are hearing.

For the moment, I would prefer the old CD because of the better fades.

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krabapple
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Postby krabapple » Sun Aug 14, 2005 1:48 am

For IV I've only looked at Four Sticks, but the fade there looks actually a little bit longer on the remaster (Led Zep Complete boxed set) than the original (Atlantic A2-19129,' manufactured by Columbia House under license' -- the A2 number makes me wonder if it's actually some sort of secret remaster itself, or if that's just due to it being a Columbia House record club release).

I see no evidence of channel reversal or phase shift. No evidence of digital clipping in either.

Everything above 21 kHz is pitch black on the old one, while the remaster has spectral content all the way to 22. Not that it should matter except to young children.

Both channels of the remaster peak 'natively' at 0 dB, whereas the rt channel of the old one peaks at -1.7 dB when the track is normalized to 0 dB. Similarly the avg levels per channel differ by about 2 dB in the old one versus 1 dB in the new. Overall the new one is on average ~2.5 dB louder than the old one, though the replaygain values for the 'native' files actually show a 3.82 dB difference (replaygain is a more sophisticated way of level-matching two files than normalizing to 0 dB, based on Bob Katz' recommendations for 'compressing' broadcast music).

Any way you look at them or try to level-match them, the remastered waveform looks more 'homogenous' across its length than the old one -- it's harder to visually tell the different sections of the song apart.

I'm of two minds about comparing the frequency points as I have before. D y'all think it's better to compare files *after* they've been normalized, or does it make more sense to compare them at 'native' levels? In either case, it's rare that one can definitively separate overall gain/trim effects from EQ.

No mattter how the comparison is done, though...and I've looked at 'Fours Sticks' files native, normalized, and adjusted according to replaygain...the remastered track shows a broad hump spanning most of the 10-20K band, that peaks around 9 kHz (about +4 dB avg for lt + rt, comparing files levelmatched by replaygain), encompassing smaller. secondary peaks at ~130 Hz (a half dB or less) and 2.3 kHz (about +1 dB).

Seems like Four Sticks on this remaster would have rather more 'presence' (pun intended) than the original issue's, at the expense of dynamic variety between sections...unless of course other tracks are mastered differently!
"I recommend that you delete the Rancid Snakepit" - Grant

Phil Elliott
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Postby Phil Elliott » Sun Aug 14, 2005 8:05 am

Channels are REVERSED on my LZ IV disc, harmonica on right channel in "When The Levee Breaks", etc ...

RSA pressing, black text on plain silver face.

250008 underneath the Atlantic logo, 756781528-2 on the inner ring.

Dropouts:

Rock And Roll:
1.04 Left channel dips, slowly recovers at the 1.11/1.12 mark.
1.25 - right channel rapidly gets brighter.

Stairway To Heaven:
5.15 -5.20 - some rapid quivering in level both channels ( ... for want of a better word)
5.28 - left channel drops out briefly
7.19 - right channel dips slightly, recovers 7.36

Going To California
1.54 - left channel drops briefly

When The Levee Breaks
Right channel is dipped from the start, until 0.32

The indexing on this disc is a bit sloppy - the beginning of Battle Of Evermore is clipped; also this along with Misty Mountain Hop, Four Sticks and (but only just) Going To California has the display countdown before it has actually finished.

When I first acquired the remaster, it became my preference, despite the annoying early fades, and a section of Going To California being removed. This was before a hard drive existed that was big enough to hold one song.

Having now loaded both my old and remastered disc on the PC and switched back and forth (compensating for the reversed channels), I can see what some say about the hardness of the tone on the remaster (the exception being MMH, which is fuller sounding on the remaster). I'm not sure how much this bothers me - in casual listening, it probably won't, whereas the original with dropouts certainly would.

Next question - given the reversed channels, is my old disc taken from the same tape as everyone elses old discs?
"If you knew what I was thinking you'd BE me."

Andreas
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Postby Andreas » Sun Aug 14, 2005 10:20 am

Phil Elliott wrote:Dropouts:

Rock And Roll:
1.04 Left channel dips, slowly recovers at the 1.11/1.12 mark.
1.25 - right channel rapidly gets brighter.

Stairway To Heaven:
5.15 -5.20 - some rapid quivering in level both channels ( ... for want of a better word)
5.28 - left channel drops out briefly
7.19 - right channel dips slightly, recovers 7.36

Going To California
1.54 - left channel drops briefly

When The Levee Breaks
Right channel is dipped from the start, until 0.32

The indexing on this disc is a bit sloppy - the beginning of Battle Of Evermore is clipped; also this along with Misty Mountain Hop, Four Sticks and (but only just) Going To California has the display countdown before it has actually finished.


I cannot confirm any of the above points. I don't notice any of these dropous...I tried several times with headphones. (And I thought of the channel reversals). And no beginning or ending of any song is clipped on my CD...I just checked the indexing, and it is correct.

Here are the peak levels for my target CD, as reported by EAC. Do you have the same numbers?

80.9
80.3
63.2
81.0
69.8
84.8
65.7
74.3

Andreas
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Postby Andreas » Sun Aug 14, 2005 10:44 am

krabapple wrote:For IV I've only looked at Four Sticks, but the fade there looks actually a little bit longer on the remaster

That's true in this case,but the difference is only about one second. On the other hand, Going To California is four seconds shorter on the remaster, and I mean four seconds of music.

Everything above 21 kHz is pitch black on the old one, while the remaster has spectral content all the way to 22. Not that it should matter except to young children.

You are right....what does it mean? Why would they filter at 21 KHz?

D y'all think it's better to compare files *after* they've been normalized, or does it make more sense to compare them at 'native' levels?

After normalization, of course. But the average volume or the volumes of some sections can still be different.

the remastered track shows a broad hump spanning most of the 10-20K band, that peaks around 9 kHz (about +4 dB avg for lt + rt, comparing files levelmatched by replaygain), encompassing smaller. secondary peaks at ~130 Hz (a half dB or less) and 2.3 kHz (about +1 dB).

Seems like Four Sticks on this remaster would have rather more 'presence' (pun intended) than the original issue's, at the expense of dynamic variety between sections...unless of course other tracks are mastered differently!

Yes, the remaster generally sounds more "present", mainly because its eq favors the vocals and accoustic guitars.

Phil Elliott
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Postby Phil Elliott » Sun Aug 14, 2005 12:01 pm

Andreas sent me the first minute of WTLB:

After the channels were swapped, I discovered that there was a one sample offset between the two channels. I brought the right hand channel forward by one sample on my disc. After doing this, with the exception of 3 errors, everything else was identical.

I get the same EAC numbers.
"If you knew what I was thinking you'd BE me."

Andreas
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Postby Andreas » Sun Aug 14, 2005 12:07 pm

Which means that I am deaf, since I did not hear (still do not hear) the dropouts.

Phil Elliott
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Postby Phil Elliott » Sun Aug 14, 2005 12:34 pm

Either that, or it's me ... I'm the only one that can hear Keith Moon laughing on the "Who Collection" mix of WGFA.

Must be me :)
"If you knew what I was thinking you'd BE me."