> There is no "correct" on tape, LP or CD -- because
> there is no standard of reproduction that will yield
> the proper result at the listener's ear.
AES recommended practice for professional audio -- Conservation of the
polarity of audio signals (Revision of AES26-1995)
Printing Date: 2011-10-05
Publication History: Pub. 1995; Revised 2001; Reaffirmed 2006; Reaffirmed
Abstract: This document standardizes the polarity of the signals at the
various interface points between different items of equipment, in particular
from the acoustical, electrical, mechanical, digital, and magnetic aspects.
Each item of equipment complies separately with the polarity requirements
for the input and output signals. (13 pages)
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May I point out that Microphones, Mixers, Analogue Tape machines, Digital
tape machines, Disk cutters and pickups, Loudspeakers must all adhere to
correct RELATIVE polarity in/out.
If not then the extensive manipulation of audio processing would not be
possible to do.
ABSOLUTE polarity meaning positive polarity giving positive polarity output
can be seen in microphones since the 30/40īs.
Mixers too at every in/out point if not they would be unusable since one
would get cancellations when trying to mix music through the equipment.
Analogue tape machines are all correct in/out BUT the exact polarity as
recorded on the actual tape was not standardized until the 80īs.
Digital equipment has been correct since the dawn of digital, 1982.
Neumann and Ortofon cutters both adhere to the correct polarity that should
be cut on vinyl disks.
Most pickups follow the vinyl disk polarity convention since the 70īs.
Most loudspeakers have at least the red binding post when fed a positive
pulse having the BASS speaker move forwards for a positive increase in front
of the speaker.
BUT if a three way speaker uses 12 dB/octave cut off butterworth filters
then for flattest FREQUENCY response then the polarity becomes LF + MF - HF
Using 24 dB Linkwitch-Riley filters where the filter are IN phase in the
crossover band we get LF + MF + HF + so the whole speaker is in the correct
I would claim that since the 80īs MOST recordings have the polarity correct
including the final release media as CD 44/16.
What the consumer market does is an entirely different matter BUT most of
the time the equipment is in the correct polarity convention.
I have Vinyl test disks with polarity test signals.
And several CD test records with polarity test signals.
And there is lot of testing devices for polarity out there in the shops.
I, personally, bought my first polarity tester from the German company EMT
in the early 70īs and this tester can measure both microphones/loudspeakers,
amplifiers, cables etc with no problems.
The Mastering Room AB
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Learn from the mistakes of others, you can never live long enough to
make them all yourself. - John Luther