Recording equalization varied widely from the introduction of electrical
recording until the supremacy of the RIAA curve in the mid-fifties. The
ascertaining and applying the correct playback equalization is one of the
most challenging aspects of disc playback.
Other respondents will supply more information in answer to your queries.
On Mon, Mar 4, 2019 at 9:26 AM Steve Smolian <[log in to unmask]> wrote:
> Companies that made 78s electrically used different systems at different
> times. This was usually indicated by a code in the dead wax, either as
> part of the matrix number or in another area. W in a circle was often used
> for Western Electric, for example. C was used by Columbia to indicate
> their own system about which I know nothing- was this their own development
> or licensed from an outside source?
> Has anyone noticed a change in recording characteristics after the date
> this was changed? Does this affect the playback equalization settings?
> Has there been a study of these systems, dates, etc.?
> If there was no change, there's not much use chasing down some of this
> Steve Smolian
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Delray Beach, FL 33483