Friday, December 24, 2010

Imbalances on Beatles Mono Releases


There is an interesting and frustrating problem with Beatles Mono releases, in that many of them are imbalanced in some way. This means that in most cases we are not listening to true Mono.

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WHY

Establishing why, or at which point, an imbalance may have occurred is tricky, at best. Working backwards, if some imbalance is noticeable at your (the consumer) end, it could be attributable to your playback gear (phonograph cartridge, balance control, speaker connections). If not the problem, it may be that you own the product of a particular run of vinyl (faulty stamper) or CD (faulty control disc) which was pressed incorrectly. Or, a step further back, the problem could have been the mother disc. Or, a step further back, the metal master for the mother. Or, a step further back, the lacquer for the mother. Or, a step further back, the Mono master reel (production master) for the lacquer. Or, a step further back, the Mono mix reel.

Playback Gear

Phonograph cartridges ought to be checked for misalignment with test records made for such a purpose. Speakers should be tested for phasing. Adjust all balance controls. Test the general alignment by playing a known balanced Mono CD (such as any Beatles CD EP), and see (1) if pressing the Mono button on your amplifier (if you have one) changes the center point (headphones best here), or (2) if any noise emanates from a speaker which you have deliberately hooked up OOPS (out-of-phase)*.

* There are several different methods for this. Check online.

Stampers, Mothers, Metal Masters, and Lacquers

Once sure that the playback gear is balanced, it may be possible to ascertain at which level of production a record or CD became imbalanced.

A record (grooved) is the end product from a metal stamper (which imprints the grooves), which is the negative from a metal mother (grooved), which is the negative from a metal master (which imprints the grooves), which is the negative from a lacquer (grooved original).

Can imbalance occur at the stamper level? Yes, it can, and I can name two ways. First, if the country of origin for the stamper is different than the country of origin for the lacquer. Where the record was pressed, quality control may have been inferior. Thus, a Greek Mono 45 may be imbalanced where the same UK 45 is not. Or, the pressing may have been deliberately manipulated. Capitol, for example, is notorious for post-processing. Second, even if the country of origin for the stamper is the same as that for the lacquer, a lapse in quality is possible.

Can imbalance occur at the mother level? Not likely, since these are metal parts from the previous level, and are not liable to any processing. While integral imbalance from shoddy parts is possible, it is not quite probable. The same applies to the metal master level.

Can imbalance occur at the lacquer level? Oh yes, and in two ways. First, processing is certainly a step in creating lacquers. One has only to notice the sonic difference between the "-1N" lacquer and "-2" lacquer for the same UK 45. In such processing, imbalance can be embedded. Second, the lacquer is literally cut by stylus, so it is entirely possible that cartridge misalignment might occur.

Now, if you have a balanced Mono vinyl, does that mean the metal stamper, mother, master, and lacquer for that vinyl were balanced as well? Almost certainly, Yes. For if the vinyl is balanced, the stamper is balanced unless some rare re-balancing occurred at the pressing stage. And if the stamper was balanced, so were the metal mother, the metal master, and the lacquer, for we cannot have a balanced mother with an imbalanced lacquer.

Master Reels and Mix Reels

One of the issues with Mono recordings is that they are oftentimes run (transferred) through Stereo tape decks at some level of production. This is risky business. For when a Mono recording meets a Stereo tape deck, the signal is split Left-Right into two separate Mono recordings. If anything goes wrong, one signal may become imbalanced by what is known as incorrect azimuth, the state in which one of the tape heads on a Stereo tape deck is not aligned with the other tape head. Any incorrect azimuth causes an out-of-phase condition which can translate into various defects, such as timing sync problems, degradation of information, loss of frequencies, and more.

The Mono master reel (production tape, or work tape) is the step before the lacquer. If the Mono master reel (the source) is played through a Stereo tape deck while the lacquer (the destination) is being cut, imbalance is possible by way of incorrect azimuth.

The Mono master reel is created from the Mono mix reel. If the Mono mix reel (the source) is played through a Stereo tape deck while transferring to the Mono master reel (the destination), or if the destination recorder is a Stereo tape deck, imbalance is possible by way of incorrect azimuth.

The Mono mix reel (the destination) is created from the original multi-track tapes (the source). If the destination recorder is a Stereo tape deck, imbalance is possible by way of incorrect azimuth (but the original multi-tracks, being separate, are not susceptible to imbalance).

All such tape azimuth problems would be minimized or eliminated if a Mono tape deck with a single head were used throughout any Mono taping process. Regretfully, EMI chose not to use Mono tape decks for many Beatles Mono tape transfers. Maybe they didn't have one... sure.

Some Mono releases purport to be from "the original master tapes." But this is a misnomer, since these releases are subject to their own remastering, cutting, and pressing. Unless the Mono mix tape itself has been checked for imbalance, and the entire chain up to the released vinyl or CD has been kept under the same quality control, imbalance is still possible.

Some bootlegs have given us access to various reels, such as Mono mix tapes and master reels. However, these bootlegs have their own transfer history which must be reckoned. Even if their source reels were originally balanced, the resulting record or CD may be imbalanced from shoddy transfer procedures or improper production routines. Sure enough, Mono bootleg tracks I've tested (I've not tested them all, of course) have imbalances.

Digital Conversion

For CD, some imbalances may have been caused during analog/digital (A/D) conversion. Even if a Stereo tape deck had never been used in the Mono mastering chain, faulty A/D conversion could account for a variety of digitally-generated errors created during the transfer of a Mono tape. But it is nearly certain that the masters for the 1987 Mono CD albums (Please Please Me, With the Beatles, A Hard Day's Night, and Beatles For Sale) were transferred with not only a two-track (Stereo) tape deck, but also a more modern (rather than vintage) one, according to the sound engineer, Mike Jarrett. As well, it seems clear that the masters for the CD 45 box set were also at some point transferred using a Stereo tape deck.

None of this, however, precludes any further digital errors, therefore making it next to impossible to say which factor was most likely the cause for imbalances on digital releases.

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WHAT

The List

Below is a list of Mono releases and needle-drops which I have tested for imbalance. I checked only CD and needle-drops, using the channel inversion method*, checking with eyes and ears for artifacts (more on this below). WAV files were ripped using both CDex and Windows Media Player.

*Open a Mono song file with Audacity (or similar audio editing program), choose "Split Stereo Track" from the arrow pull-down menu, invert one of the channels (either Left or Right), make both channels Mono (from the arrow pull-down menu), and play the result. If you hear any sound, or see any movement on the Output Level Meter, there is an imbalance. To get the visual graph for this imbalance, after you invert one of the channels, choose "Make Stereo Track" from the arrow pull-down menu, then, after selecting a portion of the track, choose "Plot Spectrum" from the "Analyze" pull-down menu.

Note that having imbalance artifacts does not automatically mean inferior sound quality.

Artifacts & Other Terminology

Test results reflect "artifacts," that is, information on one channel which is not mirrored on the other channel. If the artifacts are on both channels, and sounding like a quieter version of the track, whether the result is low or loud, relatively speaking, consider it Stereo leakage which does not, in my estimation, affect the sound (I will label these "clear"). But if artifacts have pops, as a stylus over faulty vinyl (but I don't think that's the cause), which result in db spikes (I will label these "spikes"), or sound like weak radio transmissions or digital noise (I will label these "noise"), there could be problems during normal listening.

When I say "peaks" I mean @ (at about) -db observed on the Audacity output meter, not on the Audacity spectrum plot graph (which oftentimes has different results).

"FLAC signature" signifies that, when spectrum analysis (Audacity) was performed on a Mono track undergoing a channel inversion (imbalance) test, very insignificant amounts of low-level artifacts were present, inaudible and without effect. Visual confirmation of these artifacts begins at about 17 KHz, peaking @ -72 db on the Audacity spectrum plot graph.

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WHERE

MONO CD ALBUMS with Imbalances

Please Please Me
Mono

Every song on this CD has an imbalance. There is a uniformity among the artifacts in that they all peak @ -36 or-39 db, and are clear.

With the Beatles Mono

Every song on this CD has an imbalance, but with a wide range of artifact behaviors. Peaks range from @ -6 db on the high end to -18 db on the low end. The highest-peaking songs (such as "Little Child") were fairly clear. The lowest-peaking songs (such as "Roll Over Beethoven") were noise.

A Hard Day's Night Mono

Every song on this CD has an imbalance. There is a uniformity among the artifacts on Side 1 in that they all peak @ -9 db and are half-clear. On side 2, however, every song differs, with peaks ranging from @ -4 db on the high side ("Any Time at All") to -12 db on the low end (for example, "You Can't Do That").

Beatles For Sale Mono

Every song on this CD has an imbalance. There is a uniformity among the artifacts in that they all peak @ -33 or-36 db, and are clear.

MONO CD 45 with Imbalances

The Bad

26 tracks peak @ -36 db. This would not at all be a concern, but there are spikes (popping) to @ -12 db.

"From Me to You" peaks @ -45 db, occasional spikes (not the stylus sound, but different) to @ -15 db. "Thank You Girl" the same, but peaks @ -33 db, spikes to @ -18 db.

The Good

"She Loves You" and "I'll Get You" peak @ -30 db, clear.

"I Feel Fine"/ "She's a Woman," "Can't Buy Me Love"/ "You Can't Do That," and "Ticket to Ride"/ "Yes It Is" peak @ -33 db, clear.

"Help"/ "I'm Down" peak @ -36 db, clear.

"You Know My Name (Look Up the Number)" peaks @ -15 db, spike to @ -12 db, clear.

MONO CD COMPILATIONS with Imbalances

Past Masters 1 (original)

"Love Me Do" peaks @ -39 db, clear.
"From Me to You" peaks @ - 45 db, clear.
"Thank You Girl" peaks @ -33 db, clear.
"She Loves You" peaks @ -30 db, clear.
"I'll Get You" peaks @ -30 db, clear.
"Komm Gib Mir Deine Hand" peaks @ -45 db, clear.
"Sie Liebt Dich" peaks @ -45 db, clear.

Past Masters 2 (original)

"You Know My Name (Look Up the Number)" peaks @ -12 db, clear.

MONO CD without Imbalances

To complicate matters, some Beatles CD's have no imbalanced tracks, but I don't know if this is the result of better mastering from the tapes, or if they are Mono fold-downs from some stage of production. These are:

The CD EP Box Set

The Beatles 1962-1966 (2010)

The 2009 Remasters

NEEDLE-DROPS

All results are for UK Mono. Results vary for the same song between different needle-droppers (such as between Dr. Ebbetts and pbthal) due to proprietary mastering procedures, and/or between different formats (such as between FLAC and mp3) due to disparate encoding procedures and quality control.

Since I've not done actual vinyl tests (for a variety of reasons), I can't say if these needle-drops reflect actual vinyl balance or imbalance.

Dr. Ebbetts

I did not listen to actual Ebbetts CD's, only mp3 (320 kbps) and FLAC commonly obtained.

MP3 320 kbps. Depending on the album, peaks @ -24 to -36 db, low-level digital noise. Beatles For Sale the same except not digital noise but half-noise.

FLAC. Low- and mid-frequency hiss peaking @ -48 db, and spectral analysis showed low-level artifacts. No imbalances on A Collection of Beatles Oldies, The Beatles UK EP Collection (just like the authorized issue), and The Beatles UK Singles Collection (unlike the authorized issue!).

Millennium Remasters Red Wax

I did not listen to actual Millennium Remasters CD's, only mp3 (320 kbps) commonly obtained.

MP3 320 kbps. Up to Beatles for Sale, peaks @ -18 db, noise. Help! and onward peaks @ -27 db, clear or half-clear. The Beatles (White Album) has no imbalance.

Pbthal

I listened to source material.

FLAC. All of Pbthal's work has no imbalance, only a FLAC signature.

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HOW (to fix things)

Channel Duplication Solution

If a Mono recording transferred through a Stereo tape deck is kept in "Stereo Mono" (that is, has not been "summed" to Mono) throughout the remainder of the mastering process, it may be possible at any later link in the chain, including at the consumer end, to rectify any imbalance, to some degree, by removing the most offensive channel (Left or Right), and patching that single channel through as a new Left-Right signal. However, if that Mono recording is at any point summed to Mono from its Stereo signal, without the aforementioned rectification taking place beforehand, all offensive qualities will become embedded, impossible to remove, and somewhat more noticeable as well.

I call the rectification procedure "Channel Duplication Solution." With a computer audio editing program such as Audacity, such a repair is fairly simple. CD tracks must first be ripped as lossless WAV files, but mp3 and FLAC can be edited without any conversion. Then, open any Mono song file with Audacity, choose "Split Stereo Track" from the arrow pull-down menu, decide which of the channels (either Left or Right) sounds best to you, copy that channel, paste to the more offensive channel, choose "Make Stereo Track" from the arrow pull-down menu, close and Save. Voila! You now have true Mono instead of imbalanced Mono.

This procedure can also be accomplished with analog equipment. Assuming vinyl is being tested, insert only either the Left or Right RCA plug from your turntable into the appropriate jack on your amplifier. Then, press the amplifier Mono button to produce a signal in both speakers. This method is play-only, and furthermore cannot remove any imbalance in your playback gear. If you wish to record this "fixed" Mono signal, you will need to reroute the signal with a Y-cable (check online for various ideas here).

If you repair any track in these manners, but the result sounds anything but good, or worse than it did, it probably means that the faults were embedded during the mastering process, likely by an engineer pressing the "Mono" button on a Stereo tape deck during the transference process. It could also mean that the mix itself was bad, or that the original mix and/or master tape was in shoddy condition, also embedded faults. Such tracks cannot be repaired in the manner specified.

Artifacts called "clear" in the list above will also probably not benefit from any Channel Duplication Solution. A-B listening tests, and comparative spectrum plot analysis, seemed to bear this out.

I haven't on this page given any Channel Duplication Solution results, but I may, on a song's "Source" webpage, note any such result which I find pleasing. You can also try the suggestions given: here.

WinAmp + Stereo Tool

I have also discovered a program which digitally corrects azimuth problems. It's called "Stereo Tool" (I'm using version 6.0), and it runs as a WinAmp plug-in. Very interesting and in-depth. This is more involved than the Channel Duplication Solution. However, the results are probably not very much different or better. Another downside is that it's play-only (no Save feature).

Listen to Original Mono Vinyl

Now, it might be argued that the best solution is to find Mono vinyl of the song in question. Perhaps, but there are a few counter-arguments. First, original Mono vinyl, especially early UK, is expensive, and often not found in good quality. If the purpose is to improve the listening experience, I'm not sure this does. Second, since I don't have much original Mono UK vinyl, I can't truly comment on imbalances thereon. As a matter of fact, I don't know that anyone has ever done such a study, let alone published results.

If we count upon needle-drops for study, it presupposes not only that the vinyl was perfectly original, the recording gear perfectly aligned, the mastering procedures flawless, and the transfer to CD impeccable, but also that no summing to Mono took place at any point from needle-dropper to delivery of product. It should be apparent that the same nerve-wracking parameters apply to anyone who thinks to study their own Mono vinyl for imbalances. Remember, if the entire chain isn't perfect, the test results will not be true.

Let it Be

Another solution is to leave it alone. If the Mono signal remains on discrete Stereo channels, any resulting out-of-phase behavior will be minimized, even to the audiophile’s ears. In actuality, it is very difficult to discern any difference between a balanced and imbalanced Mono signal, unless that imbalance is very pronounced.

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Tom Wise
gengar843@msn.com

Although I use quotes from sources, or cited fact, much of the material on this and other pages of my blog is original, from my own pen. This is not cut-and-paste, it is a work of art. Copyright © 2010 Tom Wise.

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