[78-L] Speed vs. Frequency

[David Lennick]

Just noting that a 2.1 TRUNCATED elliptical stylus is still one of my 
favourites for playing 78s. Also, did we ever discuss why a .7 mil stylus is 
the best for playing vertical cut transcriptions like World and Associated? Not 
for Diamond Discs, by any means, but it gives the best results on vertical ETs 
and it also plays 8-inch LangWorth better than a 2.5 mil (here I'm talking 
about the early ones, not the later ones which are clearly microgroove).

dl

DAVID BURNHAM wrote:
> Michael Biel wrote:
> 
> The groove dimensions vs top frequency is not a factor of the width of 
> the groove but the size of the stylus point front-to-back.  That is why 
> eliptical styli are theoretically capable of higher frequency response.  
> Broadcast styli were usually 2.5 mils conical, not 3 mils.  Since 
> cutting styli are chisel shaped, they have a smaller front-to-back 
> dimension than playback styli.  They also have burnishing facets to 
> polish the groove it just cut, and this might also affect the top 
> available frequency it could record.So it is not a three-to-one factor, 
> more like a two and a half-to-one in the conical styli days.
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> I am, of course, aware that cutting styli aren't conical and I know about eliptical styli.
> 
> But, unless I am mis-informed, (which is quite possible),  surely the various dimensions, (width, front to back, etc.), are proportional.  A 3 mil groove is cut with a stylus which is much less than 3 mil front to back and a 1 mil groove is cut with a stylus which is much smaller than 1 mil front to back.  But the proportions must be roughly the same.  Similarly eliptical playback styli have the same proportions whether they are 3 mil or 1 mil.  So all of these proportions being the case, I still believe a 3 mil groove would have to be recorded at 100 rpm to match the sound quality of the LP.  If I remember correctly, eliptical styli were a product of the late 60s and ten years earlier, the more complicated characteristic of the stereo groove is what required the playback stylus to be reduced from 1 mil to .7 mil.  As a side thought, this was quite a change when playing mono LPs.  It is like reducing a 78 stylus from 3 mil to 2.1 mil which is
>  near the low end of most collectors' various sizes of playback styli, (2, 2.5, 3, 3.5 and 4 mil).  So .7 mil styli must have ridden quite low in the mono LP groove.
> 
> All of this being said, dl is correct that it would be a nightmare trying to cue up an LP with 30 or more tracks on it, so for this reason, 78 rpm records are more suitable.
> 
> db
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