garyrc Posted August 4, 2022 Share Posted August 4, 2022 Did old (1960s) chart recorders use smoothing? How much? How would we compare the speaker frequency response curves we see in old copies of High Fidelity magazine with modern curves that we run with on something like REW, with 1/3 octave, 1/6 octave smoothing, etc.? 1 Quote Link to comment Share on other sites More sharing options...
boom3 Posted August 5, 2022 Share Posted August 5, 2022 Apples and oranges. It's not the recorder (yes I've used them) but the rest of the set-up. The test room is the overwhelming variable and I would take the curves you see in old High Fidelity or Audio articles as general indications of a speaker's response, but not with the precision we now have with REW and its peers. If you see near-field measurements of bass response in the later years of Audio it's pretty accurate since the room was taken out of the variables. The old chart recorders hooked to the typical General Radio BFO analyzer had "smoothing" but not by design. The inertia of the mechanical stylus (pen) created a degree of "smoothing" but not designed to be "1/3 or 1/6 octave" etc. With the exception of the later years of Audio (Mr. Heyser) I'm not sure any of the mags published raw curves, especially High Fidelity which was notorious for twiddling with the curve to make it look prettier. The exception I recall was there review of the LaScala, which got PWK riled up so much that the mag disavowed the review. 3 Quote Link to comment Share on other sites More sharing options...
Deang Posted August 5, 2022 Share Posted August 5, 2022 4 hours ago, boom3 said: The inertia of the mechanical stylus (pen) created a degree of "smoothing" but not designed to be "1/3 or 1/6 octave" etc. I read this and thought about the plotters I used to work with as a computer operator in the late 70's. Programmers used to complain about it as the data points weren't always on spot. 1 Quote Link to comment Share on other sites More sharing options...
Schu Posted August 6, 2022 Share Posted August 6, 2022 In the seventies... Punch cards? 1 Quote Link to comment Share on other sites More sharing options...
hanksjim1 Posted August 6, 2022 Share Posted August 6, 2022 Fond memories of punch cards, Fortran IV and DEC PDP 11s....NOT 2 1 Quote Link to comment Share on other sites More sharing options...
garyrc Posted August 7, 2022 Author Share Posted August 7, 2022 Protesters against the practices of the UC Berkeley administration in 1964/65 wore punch cards dangling on ribbons around their necks with "HUMAN - Do not Fold, Spindle, or Mutilate" written in big letters on them. If any of you old timers saw chart recorder sweeps of, say, Heritage speakers in the Paleolithic, let me ask my question another way, how might a chart recorder frequency sweep of a speaker look compared to a modern REW curve? Might it resemble 1/3 octave, 1/6 octave, or what? Go ahead and guess. Quote Link to comment Share on other sites More sharing options...
Schu Posted August 7, 2022 Share Posted August 7, 2022 we went to the moon with Slide rules and #2 lead Pencils... 2 Quote Link to comment Share on other sites More sharing options...
boom3 Posted August 8, 2022 Share Posted August 8, 2022 Here are a few examples of chart recorder outputs from the man himself in 1963. He also put some chart records in various editions of Dope from Hope. K400 Paper.pdf Quote Link to comment Share on other sites More sharing options...
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