I needledropped the mono version of that "Fool On The Hill" album and the title track is awfully dull or muffled. I wonder if the CSG is somehow backed in there too. I just wound up EQ'eng it as that was about all I could do.
The intended purpose of the Haeco-CSG processor was to eliminate the need to make separate mono and stereo mixes of a recording. They could take a stereo recording, run it through the processor, and it would produce so-called "compatible" stereo that could be folded down to mono with no further attention needed. As for the muddy sound, I don't know whether to blame it on the Haeco-CSG encoding, or simply how low of a priority mono LPs were by 1968. Record companies were really keen on no longer having to produce and stock mono and stereo versions of their LPs, and quite often simply put stereo LPs into mono packaging, figuring that nobody would notice or care about the difference anymore.
Interesting! The mono LP I have has a different serial number, too. So, now i'm wondering if it's a fold-down. I also bought a Flip Wilson comedy record from Atlantic Records, also from 1968, and it's also a CSG. I tried rotating the right channel by 90° but not much happened except that the sound got duller, but the wave got fatter. So, I just mastered it that way.
Not every track on a CSG-era album will use CSG - it was only if the central channel ended up too congested when summing the channels. Best to use the OOPSing process discussed in post 2 to determine whether those tracks really need it. If it ain’t broke, don’t fix it!
The intended purpose was single inventory: no more separate mono and stereo releases. While that ended up happening for LPs (even without CSG), it caused a problem for radio stations, who apparently mostly didn't have stereo cartridges, so 45s remained mono for some time, often created via CSG. The same was true for mono promo LPs, although those went away relatively quickly.
For the mono Sergio Mendes & Brasil '66 album, it was only one or two tracks that gave me issues. For the Flip Wilson album, it's just a comedy album recorded in a nightclub, so I didn't care too much . I just had a heck of a time trying to EQ it so it didn't sound so strident. It came out OK. I had to do a lot of cleanup because the record was so noisy. Isotope RX's repair assistance really came in handy there.
Sergio Mendes' "Fool On The Hill" track has been a problem forever with that crappy CSG. It's on virtually every one of his many compilations, and it's got that rotated CSG sound on every one of them. The whole green GREATEST HITS album had that CSG applied to all tracks, and the CDs that you can buy today are still laden with it. OK, so this PhaseBug is a modern day solution. Thanks for pointing it out - it works great, and I can finally achieve the undoing of this technical nightmare called CSG. But - just a bit of history regarding the "Fool On The Hill" track itself: @Grant is correct that the stock single (AM 961) of the song was released in mono. That's one way to conquer CSG, but it's mono. The album FOOL ON THE HILL was the first at A&M to receive the CSG processing, so the intent was not to issue a mono album - but they did anyway. The CSG stereo version is SPX-4160, while a mono version was pressed with the catalog number of LPX-160. That pressing was also shoved into SPX-4160 jackets and shipped out to radio stations with a "MONAURAL" sticker on it. OK so that's all mono. What about stereo? Well, this PhaseBug thing works great. But there was always a lesser-known solution involving a rare pressing. Back in the late 60s, some FM stations were starting to play more hit-based stuff including singles. They wanted stereo, so A&M began issuing some rare stereo promos to FM stations. One of these was "Fool On The Hill" issued as AM-961-S. In my travels around the Internet, I unearthed one of these - and to my delight, there was no CSG applied.
@Alexlotl: thanks for starting this thread, great information and as an old dsp/audio EE, the thread is great GeekCandy as well
In RX7, what I did was first use the suggest function in the Phase module for both channels. Second, I processed only the right channel by -90 degrees. Sounds great now!
Frank Sinatra's "Cycles" sounds so much more alive and robust in wide stereo without CSG -- This method really works!!
I always loved the Cycles album, but that CSG processing drove me crazy. Thanks to retirement I have a little more spare time to play around with stuff like this so this morning, I followed the perfect instructions @Alexlotl provided (many thanks!!) and corrected my Cycles CD, and as @batdude98 said, it's much better!
I was playing with the other Sergio Mendes album that had CSG applied, YE-ME-LE, and using the PhaseBug plugin. Curiously, I found that the right channel shift worked better at -60°, indicating that it was originally shifted +60° in the right. During this time, singers Lani Hall and Karen Philipp each had slight shifts to one side or the other. After correction, I'm hearing Lani coming from slightly left of center, and Karen coming in slightly to the right of Lani. This all sounds clearer on YE-ME-LE after a -60° phase correction. But! "Masquerade" and "What The World Needs Now", the last two tracks on the album, sounded better with a 90° phase correction! I've also found that the Miguel Rios single "A Song Of Joy" decoded better with a 120° phase shift.
I once saw a CSG box on eBay, but I didn't feel like paying $450 at the time just to answer that question.
These instructions may shed some light: http://www.audiorents.com/library/userManuals/1_HAECO_csg.pdf It sounds like the right channel to me. The instructions say the unit’s phase invert switch applies to the left channel (it’s an OOPS switch!) . With the channels summed and no CSG applied, you theoretically get +6DB. At the +3DB setting (90 degree rotation) the output will be the same amplitude regardless of the position of the phase invert switch. At the +0DB setting (120 degree rotation), then if the phase invert switch is flipped, you’ll instead get +4.5DB. Assuming the manual is correct is saying that the phase switch inverts the left channel, then for that +4.5DB to be correct, the device must be rotating the right channel. Obvious caveats apply: - Machine may have been wired up wrong. - Channels may have been switched in CD mastering - Phase of both channels may have been flipped in CD mastering.
Reading those instructions, it also strikes me as very easy for an engineer to accidentally record with the phase invert switch enabled, when in the +3DB position. That would make the right channel +90 and the left channel +180, meaning you'd have to do a +90 on the right channel, then invert both channels to put it back to rights.
Where are you seeing it's the right channel that gets rotated? All of the numbers are the same regardless of if it's the left channel that's rotated, the right channel, or both.
I've been playing with the PhaseBug plugin for Audacity, and it allows any sort of phase alteration of either channel. It doesn't seem to matter if I alter the left one way, or the right the other way, or both channels an even amount - what seems to matter is the resulting "angle" between the two, so as long as the two are 90° apart (in most cases), the resulting sound restores to normal.
Correct. Presumably some people can hear the difference of an absolute phase shift (that is, equally in both channels), but the key to CSG (and undoing it) is the relative phase shift between the channels.
Hmm, you're right now I look at it again - the sums are the same either way. From an engineering perspective though, I would have thought it would be better to keep the left channel simple with just a toggleable total phase inversion, while the right channel has the complicated phase shifting mechanics. The fact that the phase inverter switch works even when the phase shifter is bypassed would hint towards this. The wikipedia article talks about the right channel, but then it has quite a lot of information that isn't in these instructions, with an unsourced reference to an interview with a recording engineer who used the system. There's also mention of a CSG2 which may well have done things differently.
FYI, the instructions you posted are for the CSG-2. Everything could have just as easily been limited to the left channel, but I'm not sure. Neil Young Archives has both versions of his debut album (with and without CSG), and while 3 songs have different mixes, the rest are the same other than the presence of CSG. Unfortunately, even after processing the non-CSG version with PhaseBug just about every which way, I can't get a handle on exactly how the CSG version was processed. I think other things in the chain (like EQ) probably also affected the phase, which makes visual comparisons tough. I think someone would probably have to do digital captures from a CSG box to nail down exactly what it was doing.
Did some more googling, found some interesting docs. An obituary for Howard Holzer (HAECO = Holzer Audio Engineering COrporation) That would suggest CSG-2 wasn't a later model, but was just the name of the stereo-to-mono variant - 2 for 2 channels. Did the CSG-4 sum quad to mono, or quad to stereo? A manual/whitepaper for Orban broadcasting systems, 2019 A blog post about a vinyl mastering book, Larry Boden's Basic Disc Mastering This is talking about the 2013 second edition. Archive.org has the first edition, but that pre-dates Haeco CSG. Would the patent be available anywhere?
Probably, but one would need the patent number(s) to look it up. The CSG brochure I have just indicates "patents are pending".
My mind is cringing at the thought of what the quadraphonic version of CSG would've sounded like. Hopefully it never left the prototype stage.
