"There was no standard for which polarity was correct"
This has been the case since the introduction of electrical recording. As primative as you may think acoustical recording was, all cylinder and disc recording/playback systems of the acoustic era took steps to maintain accurate absolute polarity. At CBC we also checked all new mikes when they arrived to ensure that they were of the same polarity as the CBC standard but there was no industry standard governing polarity. The next problem is the equipment. All recording consoles and other studio equipment did not have a phase standard. We used a Neve portable console and whenever eq was introduced in a mike channel, the console flipped the phase of that channel. Some engineers introduced eq to every mike channel so the phase was common, but was it correct? Who knows??
"I've done enough dialog editing to know that a few male voices are quite
From my experience, (about the same length of time as yours), I would say that every human voice is asymmetrical; in fact, I would say that every natural sound is asymmetrical. Sometimes a flute or clarinet can produce a sound which is almost sinusoidal but otherwise only electronically generated sine waves and square waves are symetrical.
On Tuesday, September 30, 2014 2:44 PM, John K. Chester <[log in to unmask]> wrote:
At 12:14 PM 9/30/2014, DAVID BURNHAM wrote:
> I have not experienced nor can I imagine why a trombone would have
> negative spikes. The only explanation I can think of is that the
> absolute polarity of the microphone has been reversed, but that would
> affect trumpets as well.
The query that started this thread was about a live recording made in the
1970's. When I first started doing live sound work in 1970, I built a
device which measured polarity of microphones, because I understood that it
was important that the mics all have the same polarity. When I first
measured the several dozen mics in our collection, the results were 60% pin
2 + and 40% pin 3 +. There was no standard for which polarity was correct
-- it varied from one manufacturer to another, and even in some cases over
time with a single manufacturer. And, I doubt that polarity was checked in
manufacturing test, because one day a recording company showed up with a
brand new matched pair of Neumann mics, and we found that they had opposite
polarity. Oops! Thus, I would not be at all surprised to find that
different instruments in a 1970's recording have different polarities.
> As far as why a woman's voice would have higher spikes than a man's
> voice, my explanation, (which everybody is welcome to argue with), is
> that every human voice, male and female, has the same amount of high
> frequency energy - mainly consonants. But a male voice has much more low
> frequency energy which might tend to mask some of the high frequencies,
> especially if he's close to a mike which might lop off the spikes.
I've done enough dialog editing to know that a few male voices are quite
asymmetrical. Broadcasters discovered asymmetrical voice waveforms long
ago. For those interested in audio history, Google "Kahn Symettra-Peak" to
read about a device patented in 1959 which claimed to fix this problem.
-- John Chester