Category: Radio

There’s no escape from folded mono sound. This morning, Boss Radio 66 played the Rolling Stones’ “Out of Time”, a song that’s used very effectively in Once Upon a Time… in Hollywood.

The song was taken from the indifferently produced Metamorphosis album that ABKCO put out in ’75. Stereo elements were added to the original mono track that was given the worst sound treatment ever devised, re-channeled stereo.

As heard on the mono speaker of my Logitech Squeezebox Radio in the kitchen, the sound had the distant, hollow effect that’s typical of fake stereo when out-of-phase channels cancel each other out. On YouTube, the official copy of the recording is called the “Strings Version.”

Stereo records were introduced in 1958. In November, 1968 the White Album was released with both stereo and mono mixes. There is only a stereo mix of Abbey Road, released just ten months later. The end of true mono mixes for popular music had begun.

Ten years later, when I was working in radio, the DJ promo singles that came to the station had a stereo side for FM…

… and a mono side for AM. (The picture sleeve had a strawberry scent!)

Hitting the mono switch (a feature sadly now lacking from receivers and amps) when playing the stereo side of this record produces the same sound as playing the mono side.^* Folded mono had been heard for years, with stereo recordings played on mono FM radios, and stereo records played on mono record players.

Early stereo records had this warning.

The problem with most mono cartridges of the time was the stylus only moved sideways. The vertical modulations in the stereo grooves would not only be missed, they could be damaged by the heavy downward pressure of a stylus that wasn’t able to move up and down.

This notice appeared on later records, when mono cartridge styluses (nobody says “stylii” anymore, do they?) were made to be compatible with stereo records.

But folded mono sound can have issues, especially if there are phasing differences between the channels. I heard this effect last Monday night on Big Planet Noise. Bob Irwin played a mono 45 DJ copy of a song. In high school, when the song was new, I heard it in stereo on WBCN, listening with my Pioneer SX-440 receiver and SE-20 headphones.

There’s a lot of intentional out-of-phase sound between the channels, and I would switch the SELECTOR knob to FM MONO to hear what it did. The effect I heard 50 years ago was pretty much the same as I heard Monday night. This is the song.

Windows has a mono switch under the Ease of Access audio settings. Put on headphones, switch to mono, and you’ll hear most of what I heard, but not all. I suspect the misguided Haeco-CSG process was applied, which was a case of the cure being far worse than the problem it attempted to solve.

^* The Haeco-CSG audio process was developed at A&M Records. Thankfully, by the mid-70’s it was no longer being used for mono DJ promo records.