[78-L] Beach Boys 78s

[Michael Biel]

Ironically, some of the first stereo LPs in the spring of 1958 were 
marketed as being "compatible".  Bob Angus discussed this about 5 years 
ago and led me to some of the ads, articles, and actual records.  But by 
the summer of 58 they started the don't-play-stereo-on-mono-players 
stuff.  It was not so much the .7 mil vs 1.0 mil aspect, but the lack of 
vertical compliance in mono cartridges.  When Columbia led the charge in 
1967 to compatibility as a reason for stopping the production of mono 
records, they explained that they solve the problem by putting all of 
the low bass sounds in the center channel even if the instrument 
creating it was off to the side.  Bass under 100 Hz is basically 
non-directional (that's why sub woofers work) and in the center channel 
the needle direction is lateral.  The bass is the largest excursion part 
of the groove, and it was the vertical modulation of bass that would 
cause the most damage to a record played on a mono cartridge.  The 
further away from center a sound is, the more vertical the modulation.

Mike Biel  mbiel at mbiel.com

On 4/18/2011 11:54 PM, Steven C. Barr wrote:
> From: "Cary Ginell"<soundthink at live.com>
>> Our first stereo unit was made by Webcor. My father traded his cousin for
>> it. To get it, he had to give up a broken-down 1959 Hillman and our old
>> swing set. I think the swing set outlasted the other two items. For some
>> reason that I can't recall, I was under the impression that you couldn't
>> play stereo records with a monaural needle because it would ruin the
>> grooves. So the Webcor was used for our stereo LPs and we played all of
>> our mono 45s and LPs on a Garrard RC 88, which I still have. I was 10 so
>> what did I know?
>>
> The "needle thing" is and was fact...! LP grooves were 1 mil...but
> "stereo" grooves were .7 mil. For most "record players" of the
> sixties, playing a vinyl "stereo" disc (with .7 mil grooves( with a
> regular 1-mil "mono" needle would neatly remove the "stereo"
> details...so that the LP would still play fine in "mono" but one
> could no longer hear "stereo!" I had that happen with a number
> of LP's...!
>
> Steven C. Barr