Carpenters Stereo, Mono & CSG

[Harry]

AM Stereo was doomed by the FCC and the industry itself as to which method of stereo encoding/decoding was to be used. There were a bunch of systems, Harris, Magnavox, and Motorola were three different ones that were at least compatible with each other, and another by Kahn-Hazeltine, which was incompatible with the other three.

The FCC was "unable" to determine a winner and allowed the marketplace to pick the best of the lot. Broadcasters lined up on both sides, with some favoring the Motorola group, while other big groups aligned with Kahn-Hazeltine. And no winner was ever decided by the marketplace.

I used to have a Nissan Maxima in 1989 that had an AM stereo receiver in it. It sounded great because it allowed the AM side to use a wide-band method of reception, which allowed for a fuller frequency response in the audio. Essentially, it sounded a lot like FM.

And being the radio geek that I am (or was), I bought, and still own a Sony SRF-A100 radio that picks up all kinds of AM stereo as well as FM stereo, of course. It has a switch on the side that determines the mode of AM stereo that you wish to receive.



Those are quite sought after, and hard to find.

 

[Mark-T]

It’s been fascinating to reread this thread!

 

[Cuyler]

What a fascinating article, I'd really like to hear from Harry, Rudy and Chris on this one...

Caution: Stereo Can Be Hazardous To Your Mono
Don Elliot and Richard Carpenter
Broadcast Programing & Production Magazine Nov 1976

I have always wondered about this! Thank you for sharing!

 

[Harry]

For those looking to undo CSG processing in Audacity, there's a plugin called PhaseBug. It allows the user to shift the phase of a channel 90° either plus or minus. Works great.

 

[Rudy]

I think we found that it's either 90° or 120°, as Harry found an example of a file that cleaned up at the latter phase shift. Turns out that the settings in CSG could result in either one of these two phase shifts, based on the original operating instructions I found online.

 

[Harry]

Correct, and sometimes it's -90°, and sometimes it's +90° (or 120°)

It also depends on the pressing/mastering. I have a Vogues CD with "Turn Around Look At Me" needing a -90° right, and another CD with the same track needing a +90° right shift. I think the stereo tracks were reversed, which explains it.

 

[Rick-An Ordinary Fool]

For those looking to undo CSG processing in Audacity, there's a plugin called PhaseBug. It allows the user to shift the phase of a channel 90° either plus or minus. Works great.

I don't see this plug in, maybe I'm running an older version? I see one called Phaser.

 

[Harry]

You have to add it to Audacity.

PhaseBug by BetabugsAudio - Modulation (Flanger / Phaser / Chorus / Tremolo) Plugin VST

PhaseBug's primary function is to shift the phase of an incoming audio signal. This is a critical function in fixing source signals that hav...

www.kvraudio.com

 

[Rudy]

I added that same plugin to Sound Forge--any plugin that uses VST should work with most of the popular sound editors out there.

 

[Harry]

Playing with PhaseBug, I'm not sure I've stumbled onto something worthwhile, but basically, instead of tilting one channel 90° in one direction or another, what about shifting both channels 45° - one in one direction, the other the opposite way?

I've done it to a few records and am finding that the results *may* sound a little more like natural stereo. There are some records, like Bossa Rio, where even when one channel is shifted 90°, I'm still hearing an unfocused bass sound, like it's still "smeared". Is there any reason to think that the original track-tilting didn't go both ways, each 45°? Or am I just hearing things that I want to hear?

 

[Rudy]

The original process only applied the phase adjustment to one channel, so I would be apt to adjust it that way. The opposite (unprocessed) channel was fed through transformers so that there would be no time delay between the channels.

The key adjustment in the unit was a three-position switch called "Center Channel Buildup." It had settings of +3, 0 and -3. Presumably the +3 setting was what HAECO recommended for processing stereo LPs, whereas the 0 and -3 settings were used to produce monaural output from a stereo signal, in order to get the correct balance of the summed information. It was still possible to use 0 and -3 for stereo LPs, but they would include a lot of vertical (out of phase) information in the groove, so it was not recommended.

So the +3 setting I am guessing is what most CSG LPs used, which would have been the 90° phase shift, with the 120° shift coming from the 0 setting.

The operating instructions include the following:

 

[Rick-An Ordinary Fool]

I'm most curious about the 45 of Merry Christmas Darling regarding this PhaseBug filter. It's the only single released by the Carpenters that never got a mono pressing. I have a WLP promo 45 both sides are Merry Christmas Darling and both sides have black lettering, both are stereo, both sides use that HAECO CSG processing which says on the label can be played either in Stereo or Monaurally. I mean why not just make a mono pressing like all the other promo single 45's that contain both a mono and a stereo side.

I have another WLP 45 w/ MCD and the flip is Mr Guder and again both are Stereo and both use that CSG processing and both are in black lettering (which usually designates mono)

Is there a way with this PhaseBug to capture a true mono recording of Merry Christmas Darling and Mr. Guder from these 45's with the CSG?

 

[Harry]

Is there a way with this PhaseBug to capture a true mono recording of Merry Christmas Darling and Mr. Guder from these 45's with the CSG?

Theoretically, you wouldn't need anything other than the basic CSG'ed recording. Rip it into your computer, load it into Audacity, then use the "Mix Stereo down to Mono" function. If the CSG guys were right then simply collapsing their rejiggered stereo down to mono should produce a proper mono mix.

 

[Rick-An Ordinary Fool]

Theoretically, you wouldn't need anything other than the basic CSG'ed recording. Rip it into your computer, load it into Audacity, then use the "Mix Stereo down to Mono" function. If the CSG guys were right then simply collapsing their rejiggered stereo down to mono should produce a proper mono mix.

Thanks for the tip.
I ended up doing this today, realized I didn't even have this 45 ripped to my computer. So I took the better of the 2 CSG 45's of MCD. The stereo one is so hard to listen to, the sound is just bouncing all around and very phasey. The fold down mono worked better than I thought and sounds really good, Karen is much more centered and her vocal is a tad bit more to the front and that phasey sound is gone. I don't think she sounds quite as up front in the mix as some of the other official mono 45's but it's close enough for saving this one to my library. I like this mono mix.

 

[Harry]

By the way, if you're attempting to undo the CSG on "Merry Christmas Darling", you need to tilt the right channel +120°. It's not the standard 90.

 

[Rudy]

Interestingly enough, the instructions for the CSG contraption hints at using to sum stereo down to mono and have a better balance between center and left/right information (primarily, its 0 and -3 center buildup settings). I've thought of trying that myself to create a mono version of a stereo track, as it may come out better than summing them together.

 

[StaxOWax]

I just reached out to the email address on the Carpenters fan page asking about the possibility of a release of those original mono mixes. I've been working with a local AM radio station to expand their library and would love to have those mixes to include. That would be amazing!

Maybe if more of us reach out asking about the possibility of such a comp, Richard would be more inclined to consider one...

As a sidenote - does anyone here know if those emails actually reach Richard?

 

[Harry]

As a sidenote - does anyone here know if those emails actually reach Richard?

My understanding is that Richard Carpenter is essentially "unplugged". He doesn't engage in online activity - and doesn't want to.

 

[StaxOWax]

My understanding is that Richard Carpenter is essentially "unplugged". He doesn't engage in online activity - and doesn't want to.

Ahh, darn. I suppose there is little chance my email will reach him, then.

That said, I certainly respect his decision to be "unplugged."