[78-L] Frequency Response/Range for 78's

[Doug Pomeroy]

The article from 1953 in Audio Engineering magazine, to which I referred
I my original post, was written by R. C. Moyer.  I have just received a response
from Nick Bergh: 

> Hi Doug,
> 
> I believe the Moyer article is incorrect regarding the 1938 head improvement.  Original engineering documents and my own experiments with the Victor hi-fi cutter from 1932 confirm they were doing 10kHz in 1932.  It was dumbed down fairly quickly since nobody could play back 10kHz at home.  I think collectors could be correct saying that there is occasional response up to 12kHz in 1932/1933 Victor discs, which can be caused by poor adjustment of the hi-fi cutter.  It should be fairly rare and more of an accident probably.  They were really only after 10kHz.  The reason the 1938 graph shows response to 8kHz is that they inserted a low-pass filter in the recording chain.  This was removed in the late 40s.  Nothing major changed from the 1932 cutter design until they adopted the Westrex 2A feedback cutter in the late 1940s, which is a very different sound.  All the other changes in sound quality from the 1932 hi-fi systems to 1947 are due mostly to the electronics, filters, mics, limiters, etc. rather than the cutting head.  The 1932 gear sounds quite good.
> 
> Best,
> Nick


Doug Pomeroy
audiofixer at verizon.net