Baptist historian Bruce Gourley outlines four main views of Baptist origins: (1) The modern scholarly consensus that the movement traces its origin to the 17th century via the English Separatists, (2) the view that it was an outgrowth of Anabaptist traditions, (3) the perpetuity view which assumes that the Baptist faith and practice has existed since the time of Christ, and (4) the successionist view, or "Baptist successionism", which argues that Baptist churches actually existed in an unbroken chain since the time of Christ.
What does the perpetuity view assume?
that the Baptist faith and practice has existed since the time of Christ

West in 1930 and later P. G. A. H. Voigt (1940) showed that the early Wente-style condenser microphones contributed to a 4 to 6 dB midrange brilliance or pre-emphasis in the recording chain. This meant that the electrical recording characteristics of Western Electric licensees such as Columbia Records and Victor Talking Machine Company in the 1925 era had a higher amplitude in the midrange region. Brilliance such as this compensated for dullness in many early magnetic pickups having drooping midrange and treble response. As a result, this practice was the empirical beginning of using pre-emphasis above 1,000 Hz in 78 rpm and 33 1⁄3 rpm records.
Whom found Wente-style condenser microphones helpful?
P. G. A. H. Voigt

RCA 45s were also adapted to the smaller spindle of an LP player with a plastic snap-in insert known as a "spider". These inserts, commissioned by RCA president David Sarnoff and invented by Thomas Hutchison, were prevalent starting in the 1960s, selling in the tens of millions per year during the 45 rpm heyday. In countries outside the U.S., 45s often had the smaller album-sized holes, e.g., Australia and New Zealand, or as in the United Kingdom, especially before the 1970s, the disc had a small hole within a circular central section held only by three or four lands so that it could be easily punched out if desired (typically for use in jukeboxes).
How many spiders were sold in the 45 rpm heydays?
tens of millions per year