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In Reply to: RE: More about Absolute Polarity posted by harecording on December 16, 2008 at 19:48:50
"99.9 percent of the speakers made today move out first, using negative polarity." Huh? HUH???
The writer means "drivers", not "speakers", but let it pass. Or, not -- the huge majority of designs today incorporate crossovers that require the polarity of the bass driver, say, to be opposite that of the mid. So which one may be discovered to "move out first"?
Besides which, the writer displays a manifest confusion here between electrical polarity and acoustic polarity. Most designers will tell you they have wired their drivers so that when the + on a battery is connected to the red terminal, the driver will move forwards. This is an unwritten convention of the trade, but one that JBL alone (I believe)ignored, originally, springing as they did for the opposite. But that's electrical polarity.
Acoustic polarity, the subject of both Dan Shanefield's letter and HiOnFi's post, is altogether different and separate. Acoustic polarity recognizes the undisputable fact that most acoustic instruments have a polarity signature. They produce, most commonly, compression transients -- although a few do produce rarefaction. When these signatures are reversed by an audio system, the instruments sound wrong. Specifically, the compression transients sound muffled. That is why acoustic polarity really matters and electrical polarity remains tertiary at best.
Throughout recorded history, owing to a lack of specific directions or standards, our delivery media have incorporated a mixture of the two polarities. Sides can be different from each other, cuts can even sometimes alternate, and worst of all, a track mix can involve both recorded polarities, making a mish-mash of the music. This is just another reason why simply-miked and unprocessed (un-toyed-up) recordings can sound so great, so natural.
But, a further caveat: Whatever the polarity aspect of the recording or the reproducing system may be, the requirement is for a compression-type instrument to produce a compression transient from the loudspeaker. And compression transients are produced only by out-going driver motions. There can be no compromise.
When the poster says, "By flipping all channels to acheive 'absolute polarity', you are getting closer to positive polarity, which would make for absolute polarity IMO" one can only be perplexed by the sloppy thinking and/or writing.
The man does however get a couple of things right:
There is also a misconception that phase and polarity are the same. They are not.
Indeed not. Although, polarity is one specific and singular condition of phase. Also it is binary, either 0 or 180.
The fact that a Behringer or any other processor allows for polarity flipping does not mean that it facilitates or allows for absolute phase.
One notes some additional confusion there (besides that poignant substitution of "phase" for "polarity"). Nothing, but nothing "facilitates or allows" for correct polarity (i.e. absolute polarity) except for the human ear. The ear here is the ultimate, and just about the only arbiter.
We remain...
Poles Apart
Follow Ups:
I have read many things about what audiophiles say about absolute polarity. Some say that the polarity should be reversed on all channels, which is said to improve something. I think that is a bunch of crap. That is why I said what I did about inverting the channels on the Behringer. If inverting both channels is your version of absolute polarity, then go for it. But that is not the answer.From the Rane Pro Audio Reference:
Polarity:
A signal's electromechanical potential with respect to a reference potential. For example, if a loudspeaker cone moves forward when a positive voltage is applied between its red and black terminals, then it is said to have a positive polarity. A microphone has positive polarity if a positive pressure on its diaphragm results in a positive output voltage. [Usage Note: polarity vs. phase shift: polarity refers to a signal's reference NOT to its phase shift. Being 180° out-of-phase and having inverse polarity are DIFFERENT things. We wrongly say something is out-of-phase when we mean it is inverted. One takes time; the other does not.]
Edits: 12/17/08
If you are dumb enough to put DC on a driver....go for it. I would never put a battery on a speaker. That's stupid.
Touching battery leads to a driver is a common industry practice to verify the pole markings. It would be stupid to accept those markings without verification.
And no, we're not talking car batteries here. Give me a break.
Poles Apart
Actually, using a 9v battery is a very common way to quickly verify + and - terminals on a speaker. Ive been in the pro audio industry for 20 years and people have been doing this (for good reason) commonly all along.
Why do you need to verify pole markings? Your high end manufacturers can't do that right? What hard stuff are they screwing up.
It is not an industry accepted practice. I know too many people in recone shops to know the truth.
You can put a 9volt battery on a decent loudspeaker and it wont
hurt it whatsoever
To think putting a small DC voltage on a loudspeaker will damage
it is dumb
I wouldnt recomend a DC voltage like that on a tweeter or a compression
driver
Your talking a fraction of xmax from a small DC battery on a woofer
or mid driver
ff
Do it on a new speaker from any of the major manufacturers and see if your warranty is still valid.
Stupid because.....?If 1.5V DC damages a woofer, the woofer must be a real P-O-S.
Guy's, I implore you...do not blow your woofers using
a whopping 1.5V D cell battery :)
Edits: 12/17/08 12/17/08
9V has been proven to burn some coils. A little DC may not do the thing in right away. It may contribute to a future failure. This applies to low W drivers mainly. DC is a speakers enemy.
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